Air

Metal composition of fine particulate air pollution and acute changes in cardiorespiratory physiology

Health Canada is responsible for conducting health risk assessments on air pollution as part of the Clean Air Regulatory Agenda. This includes assessment of the health effects of air pollution produced by industry to support development of regulations governing industrial emissions. One component of industrial air pollution is a mixture of fine particulate matter (PM2.5), which is known to have negative effects on health. However, the exact chemical components of PM2.5 that contribute to negative health effects are not well understood. In this study, Health Canada sought to determine whether the effects of PM2.5 on various physiological measures were affected by the metal composition of the particles. Healthy young adult volunteers spent eight hours per day for five consecutive days either at a site very close to a steel plant, or at a site several kilometers removed from the plant. Measures of lung and circulatory system functions were assessed in the volunteers during this period. In addition, the level of different metals within the fine particulate matter were measured and compared between the two sites, allowing the effects of these metals on lung and circulatory system function to be evaluated. The results showed that increases in the metals calcium, cadmium, lead, strontium, tin, vanadium and zinc were associated with increased heart rate, increased blood pressure, and decreased lung capacity. Therefore, specific metals present in particulate air pollution may have negative effects on circulatory system and lung functions. Health Canada will use the results of this study to better understand the health effects associated with exposure to particulate air pollution. Results of this research are published in Environmental Pollution, 2014, 189, 208-214.

Risk assessment for cardiovascular and respiratory mortality due to air pollution and synoptic meteorology in 10 Canadian cities

Health Canada is responsible for conducting health risk assessments of air pollution as part of the Clean Air Regulatory Agenda. The impact of air pollution on human health depends, in part, on weather conditions. However, the precise extent to which air pollution and weather patterns interact to influence health remains unclear. In this study Health Canada, in collaboration with researchers from Texas Tech University, sought to more fully characterize the impact of air pollution and weather conditions on human health. Specifically, Health Canada analyzed data collected from 1981 to 1999 in 10 Canadian cities. Air pollution measurements focused on levels of four gases (carbon monoxide, nitrogen dioxide, ozone and sulphur dioxide), while daily weather conditions were classified into one of six stable conditions using a scale named the ‘Spatial Synoptic Classification’. The impact on health was evaluated using data on how many people died in the cities each day, and whether those deaths were due to respiratory problems, cardiovascular problems, or other non-accidental causes. Health Canada also explored whether the impact of weather and pollution on health varied depending on the season. The results demonstrated that each of the four gases increased the risk of death, and that the effects of the gases depended on both the weather and the season. These results demonstrate that when considering the impact of air pollution on human health, it is important to also consider seasonal data and information about weather. Health Canada will use the results of this study to better understand the health effects associated with exposure to air pollution. Results of this research are published in Environmental Pollution, 2014, 185, 322-332.

Ambient particulate air pollution and acute lower respiratory infections: A systematic review and implications for estimating the global burden of disease

Health Canada is responsible for the assessment and management of health risks to Canadians associated with exposure to indoor and outdoor sources of combustion-derived air pollution. Acute lower respiratory infections (ALRI) are a class of diseases that include pneumonia and bronchiolitis, and account for nearly 20% of deaths in young children worldwide, including Canada. Many studies have previously shown that increased levels of outdoor air pollution correlate with increased incidence of ALRI. Most of these studies examined the effects of short-term exposure to air pollution in developed countries, with a smaller number of studies conducted in developing countries. In this study Health Canada, in collaboration with researchers from the Health Effects Institute, aimed to re-assess previously-published data to carefully define the extent to which risk of ALRI increased following exposure to air pollution. The study focused specifically on one form of air pollution, namely fine airborne particulate matter (PM2.5). To this end, data were analyzed from 73 research papers from many different countries examining the association between air pollution and ALRI, leading to a precise estimate of the extent to which specific amounts of increased PM2.5 increased risk of ALRI. This analysis strengthens the evidence for a causal relationship between exposure to PM2.5 air pollution and the occurrence of ALRI. It also provides a basis for estimating the global burden of deaths attributable to ALRI that is not influenced by the wide variation in regional fatality rates. Health Canada will be able to use the results of this study to inform guidelines aimed at controlling levels of particulate air pollution, and to better understand how exposure to particulate air pollution is associated with increased risk of ALRI. Results of this research are published in Air Quality, Atmosphere and Health, 2013, 6, 69-83.

Association of weather and air pollution interactions on daily mortality in 12 Canadian cities

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. The impact of air pollution on human health depends, in part, on weather conditions. In this study, Health Canada, in collaboration with scientists from Texas Tech University and the University of Miami, used data collected during the summer over 28 years (1981-2008) from Canada’s 12 largest cities to examine how weather conditions and air pollution interact to impact health risks. Air pollution measurements focused on the levels of fine airborne particulate matter (PM2.5), and concentrations of nitrogen dioxide, ozone, and sulphur dioxide. Daily weather conditions were classified into one of six stable conditions using a scale named the ‘Spatial Synoptic Classification’. To evaluate health, death rates from any non-accidental causes were incorporated into the analysis. The results showed that unusually high levels of pollution are more likely to occur when the weather is hottest, and that the risks to health associated with high levels of pollution were also greatest in hot weather. Furthermore, the risks of increased air pollution on human health could be estimated more accurately when more than one type of pollutant was considered in a single analysis. This study demonstrates that the risks of air pollution to human health are affected by weather patterns. Importantly, the study also found that more accurate estimates of the risks of air pollution to human health are obtained when more than one pollutant is considered within the analysis. Health Canada will be able to use the results of this study to generate more accurate predictions of the impact of daily pollution levels on human health, and to develop improved public health warnings due to air pollution during specific weather types. Results of this research are published in Air Quality, Atmosphere and Health, 2015, 8(3), 307-320.

A case-control study of medium-term exposure to ambient nitrogen dioxide pollution and hospitalization for stroke

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Previous studies have found that day-to-day increases in air pollution are associated with increased risk of stroke. However, studies looking at long-term exposure to pollution have produced mixed results. One explanation for the lack of consistency may be that the long-term studies estimated air pollution over a fairly large geographical area, so may poorly represent actual exposure of individuals. In this study, Health Canada generated highly localized estimates of air pollution, and used these estimates to assess whether these levels of air pollution were associated with risk of stroke. The component of air pollution examined was nitrogen dioxide (NO2), which is a gas produced by traffic. Health Canada estimated levels of NO2 across the city of Edmonton, to a geographical resolution of less than 50 meters. To determine whether air pollution increased the risk of a stroke, NO2 levels were estimated near the homes of patients that visited the emergency department of hospitals. In total, data were collected for 4,696 stroke patients (and 37,723 patients who had not had a stroke and who were used for comparison). There was no association between NO2 levels estimated across the course of a year, and the number of patients who presented to emergency departments for treatment for stroke. Therefore, while previous studies have identified day-to-day changes in air pollution associating with stroke risk, this study found no clear associations over a more extended period of time, even when highly localized estimates of air pollution exposures were used. Health Canada will use the results of this study to inform how future experiments on the health risks associated with air pollution should be conducted. Results of this research are published in BMC Public Health, 2013, 13, 368-376.

Environmental Particulate Matter Induces Murine Intestinal Inflammatory Responses and Alters the Gut Microbiome

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. One component of air pollution is fine particles produced from vehicle exhaust, industrial emissions, and windblown soil. This fine particulate matter (PM2.5) has been associated with diseases including stroke, heart problems, and lung cancer. Most research on the health effects of PM2.5 has focused on inhalation, with very little research on the effect of PM2.5 on the gut. This is important as PM2.5 can be ingested through consumption of contaminated water or food. Also, when PM2.5 is inhaled it becomes trapped in the mucous lining the lungs, which is then transported out of the lungs and swallowed. In this study Health Canada, in collaboration with researchers from the Universities of Calgary and Alberta, exposed mice to PM2.5 introduced into the gut to explore the effects of PM2.5 ingestion. Short-term exposure led to increased permeability of the gut (making it easier for substances to enter the blood from the gut), changes in the immune cell production in the spleen, changes in the activity of genes involved in the immune system, and increased release of molecules responsible for immune system activation. These effects were similarly increased following long-term exposures, which also changed the types of bacteria and yeast present in the gut, and altered the functioning of the colon. Furthermore, in a mouse model for irritable bowel syndrome (IBS), long-term exposure increased IBS-like symptoms. Therefore, this study demonstrates that consumption of PM2.5 alters the normal composition of bacteria and yeasts in the gut, and increases activation of the immune system. Health Canada can use the results of this study to better understand the health effects of PM2.5 exposure. Results of this research are published in PLoS One, 2013, 8(4): e62220. doi:10.1371/journal.pone.0062220.

Ambient ozone concentrations and the risk of perforated and non-perforated appendicitis: A multicity case-crossover study

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Ozone is one of the gases that contribute to air pollution. Previously, Health Canada identified an association between ozone levels and the incidence of appendicitis in Calgary. Appendicitis is a common condition that affects 1 in 15 Canadians at some point during their lives. It is treated by removal of the appendix, which is a small extension of the large intestine. In more severe cases, the appendix can rupture, resulting in the contents of the intestine leaking into the abdomen – this is called perforated appendicitis. In this study Health Canada, in collaboration with scientists from several Canadian universities, extended their previous study by examining the relationship between ozone levels and appendicitis incidence in many Canadian cities. The work was done to determine if there is a consistent association in order to strengthen the findings from the original Calgary-based study. This study also examined whether the association between ozone and appendicitis was stronger for perforated or non-perforated appendicitis. Data were analyzed from 35,811 patients hospitalized for appendicitis from 2004 to 2008 in 12 Canadian cities, together with measurements of the daily maximum ozone levels from each city. The data showed that higher levels of ozone were associated with increased incidence of perforated appendicitis. This study strengthens the evidence that higher levels of ozone may increase the risk of appendicitis, particularly for the more severe form of appendicitis. Health Canada will be able to use the results of this study to better understand potential health consequences associated with elevated ozone levels in Canadian cities. Results of this research are published in Environmental Health Perspectives, 2013, 121(8), 939-943.

Cardiovascular impacts and micro-environmental exposure factors associated with continuous personal PM2.5 monitoring

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. One component of air pollution is fine particles. Exposure to this fine particulate matter (PM2.5) is thought to have negative effects on human health, particularly on the heart and lungs. While PM2.5 in outdoor air has been well described, indoor sources have been less thoroughly characterized. This is particularly important given that people typically spend most of their time indoors. In this study Health Canada, in collaboration with scientists from the University of Michigan and the US Environmental Protection Agency, explored whether specific activities (including indoor activities) led to greater PM2.5 exposure, and whether exposures were associated with negative effects on the heart and lungs. The data used in this study were collected in the Detroit Exposure and Aerosol Research Study (DEARS), which was a 3-year study monitoring air quality and human health between 2004 and 2007. Data for the present study came from participants who, for five days in the summer and again in the winter, recorded their activity every 15 minutes, with extensive measurements of air pollution made throughout this time. Participants were tested for various measures of heart and lung function. Indoor activities that resulted in higher PM2.5 exposure included cooking and car-related events, and increased exposures resulted in changes in heart rate, and in the width of a blood vessel that carries blood to the arm. The study demonstrated that indoor PM2.5 exposures may be associated with cardiopulmonary effects. Health Canada will be able to use the results of this study to better understand the potential health risks associated with indoor air pollution, including a better understanding of the source of this pollution. This research is published in the Journal of Exposure Science and Environmental Epidemiology, 2014, 24, 337-345.

Urinary and breast milk biomarkers to assess exposure to naphthalene in pregnant women: An investigation of personal and indoor air sources

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Naphthalene is a gas commonly detected in indoor and outdoor environments, though most human exposure occurs indoors from a variety of sources including pest control products, cigarette smoke, cooking and wood smoke. Exposure in sufficient quantity may be harmful to human health, as naphthalene is thought to be a possible carcinogen. In order to better understand the health effects of naphthalene exposure, it is important to define levels of exposure in Canadian homes, and determine how that relates to naphthalene levels within the body. Pregnant women are of particular importance in assessments, as physiological changes during pregnancy may alter the effects of toxins, and infants may be more sensitive. In this study Health Canada collaborated with scientists from Ontario, Quebec and the USA, to quantify naphthalene exposures for 80 pregnant women in Ottawa, Ontario. Samples were collected during two 24-hour periods within a single week during pregnancy, and on one occasion after birth. Naphthalene levels in the air were measured using monitors placed in living rooms, and through monitors on the volunteers. Markers of naphthalene exposure were measured in urine and in a sample of breast milk taken 2-3 months after birth. For most women, naphthalene levels in the air were similar across the different sampling times and across the different methods used for air sampling. Markers of naphthalene exposure in the urine were also similar over time, and were predictive of levels in breast milk. However, there was no clear relationship between levels of naphthalene found in the air and within bodily fluids. These data suggest that naphthalene in indoor air is a poor predictor of the amount in bodily fluids. Health Canada will be able to use these results to improve methods for monitoring naphthalene exposure. This research is published in Environmental Health, 2014, 13(1), 30-41.

Presence of other allergic disease modifies the effect of early childhood traffic-related air pollution exposure on asthma prevalence

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Traffic-related air pollution has been identified as a risk factor for the development of asthma in children, and exposure in early childhood may be particularly important. Indeed, strong associations were previously reported between traffic-related air pollution at the time of birth and risk of asthma. In this study Health Canada, through a multi-centre international collaboration, collected data from 1497 children aged 5-9 in Toronto in 2006 to determine whether lifetime exposures to traffic-related air pollution is associated with risk of asthma. The gas nitrogen dioxide (NO2) can be used as a measure of traffic-related air pollution. To determine lifetime NO2 exposure, the home, school and daycare addresses were collected for each child, and NO2 levels at each address were calculated based on historical nearby NO2 measurements, adjusted to account for local features such as highways and major roadways. The study found that traffic-related air pollution partially explained the prevalence of environmentally induced asthma, although other unmeasured risk factors may also play a role. This study supports that traffic-related air pollution exposure in early childhood contributes to the development of allergic asthma in children. Research is also needed to examine the role of other factors, particularly in combination with traffic-related air pollution.  These results are supportive of Health Canada's efforts to protect Canadians from the health effects of air pollution. Results of this research are published in Environment International, 2014, 65, 83-92.

Comparison of remote sensing and fixed-site monitoring approaches for examining air pollution and health in a national study population

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Outdoor air pollution has been implicated as a risk factor for health problems including asthma, allergies and chronic bronchitis. However, in order to best determine health consequences of air pollution, levels of pollution need to be measured over long periods of time. Traditionally, pollution has been measured at ground level at regulatory monitoring centers that form part of Canada’s National Air Pollution Surveillance (NAPS) Network. However, data from satellites have more recently been used to estimate ground level pollutants including small airborne particles, and the gas nitrogen dioxide (NO2).  In this study Health Canada, through a multi-centre international collaboration, sought to determine whether estimates of air pollution collected by satellite were comparable to those collected at the NAPS regulatory monitoring centers, and to determine whether these estimates were associated with reported adverse health outcomes. Historical data collected by satellite and through regulatory monitoring centers were compared with the prevalence of asthma, allergies and chronic bronchitis, as determined through the Canadian Community Health Survey (a national sample of individuals 12 years of age and older). The data showed that both methods of measuring air pollution produced similar results, and generated similar estimates of human health risk. This new research suggests that data from satellites circumnavigating the earth can provide exposure information that is comparable to ground data and can cover much more of the Canadian population. As a result of this experiment, Health Canada will be able to use both ground and satellite data to estimate exposure to outdoor air pollution in Canada and better understand its health effects. This research is published in Atmospheric Environment, 2013, 80, 161-171.

Estimates of global mortality attributable to particulate air pollution using satellite imagery

Health Canada is responsible for conducting research to support health risk assessments on air pollution as part of the Clean Air Regulatory Agenda. One component of air pollution is fine particulate matter (PM2.5) carried in the air that are derived from a number of sources including combustion of fossil fuels, burning of wood for home heating, forest fires, and dust. This airborne particulate matter has been linked to increased risk of death from cardiovascular disease, cardiopulmonary disease, and lung cancer. Traditionally, levels of particulate matter have been measured at ground level through monitoring centers. However, estimates can now instead be derived using information collected by satellites, thereby allowing the estimation of particulate matter air pollution on a global scale. In this study Health Canada, in collaboration with scientists from several Canadian research institutions, sought to use satellite data to estimate the extent of the global burden of death that might be attributed to exposure to particulate matter air pollution. Global estimates of particulate matter levels were generated from satellite data and these levels were compared to data from previous studies that quantified the link between particulate matter exposure and increased mortality. In this way, Health Canada was able to predict death rates across the world based on the satellite-derived levels of particular matter. It was found that 8% of deaths were attributable to particulate matter exposure worldwide. This study shows that satellite data can be used to determine pollution levels globally, and that these estimates can be used to evaluate the impact of global pollution on human health. Health Canada can use the results of this study to inform management of air quality in Canada.  Results of this research are published in Environmental Research, 2013, 120, 33-42.

Estimation of the Arctic aerosols from local and long-range transport using relationships between 210Pb and 212Pb atmospheric activity concentrations

Health Canada aims to reduce the health and safety risks associated with different types of radiation, including naturally occurring radiation within the environment. Wind patterns and atmospheric conditions have helped to increase the levels of naturally occurring radiation present within the Arctic (i.e. by transporting radon and radon progeny to the Arctic from a far). In some cases, natural radioactivity, such as long-lived radon decay products lead (210Pb) and polonium (210Po), can accumulate in high enough levels to become possible health concerns or limiting factors in country food consumption by indigenous populations. In this study, Health Canada sought to identify a possible indicator that would explain how specific air masses from mid- and low-latitudes would carry the naturally occurring 210Pb and 212Pb to the Arctic and to estimate the difference in contributions from local and long-range systems. This was done by analysing the existing long-term atmospheric 210Pb and 212Pb monitoring data collected from the Canadian Radiological Monitoring Network at locations between 42.1º and 82.5º north latitudes. Detailed monthly average 210Pb concentrations, winter averages (3-month average from December to February) and summer averages (3-month average from June to August) were calculated for all monitoring stations across Canada. The ratio of winter average over summer average of 210Pb concentration increased in tandem with the increasing latitude. Results of this research suggested that the elevated level of 210Pb in the Arctic in winter is due to radon and radon progeny produced naturally in the environment as well as from industrial activities (such as mining, hydraulic fracturing and coal burning for power generation) outside of the Arctic region. Radon and radon progeny are carried largely from mid latitudes to the Arctic through long-range atmospheric transport.  Health Canada will use the results of this study to estimate the increased 210Pb activity level in the Arctic region due to long-range transportation.  The results of this research are found in the Journal of Environmental Radioactivity vol-141, page 123-129.

Impact of Humidity on Speciation and Bioaccessibility of Pb, Zn, Co and Se in House Dust

Health Canada is responsible for providing advice to other government departments on methods to improve Human Health Risk Assessments for metals in federal contaminated sites. This project investigates why some metals are more bioaccessible (available for biological uptake) in indoor dust than in outdoor soil, which is an information gap in residential risk assessments. Laboratory experiments were conducted to determine whether metal compounds in dust undergo chemical reactions in the indoor environment that result in an overall increase in metal bioaccessibility. House dust samples were exposed to high moisture levels that may be found indoors (such as a damp carpet or a window well during winter months). The solubility of the metals in the dust samples was measured in simulated stomach acid before and after 4 months of exposure to these humid conditions. Lead and zinc showed an increase in solubility, selenium showed a decrease in solubility, and cobalt showed a variable response. Detailed X-ray analysis demonstrated that lead compounds had actually transformed into more soluble compounds under humid conditions. These results helped to explain the greater bioaccessibility of certain metals in house dust compared to soil, and contributed to Health Canada’s ongoing development of dust guidelines for the Federal Contaminated Sites Action Plan and risk assessment approaches for metals under the Chemicals Management Plan. Results of this research are published in the Journal of Analytical Atomic Spectrometry, 29(7), pp. 1206-1217.

Analysis of Selected Phthalates in Canadian Indoor Dust Collected Using Household Vacuum and Standardized Sampling Techniques

Health Canada conducts research and assessments of chemicals in order to protect Canadians from the potential health risks of various substances. Phthalates are widely used in the cosmetic and personal care sectors as anti-foaming agents, dispersants, and emulsifiers. They can easily be released into the environment over time from these consumer products, and have been detected in a variety of environmental and biological samples. Health Canada is responsible for assessing the potential health risks to Canadians of these substances. In this study, Health Canada sought to develop a new analytical method for the measurement of phthalates in house dust. Two different sampling techniques for the analysis of phthalates in indoor dust were investigated: household vacuum dust samples obtained from vacuum systems used by the study participants as part of their regular housecleaning routine, and fresh dust samples collected using a standardized sampling technique. The new analytical method was used for the analysis of selected phthalates in 126 house hold dust samples and demonstrated high sensitivity. The two sampling methods provided comparable results for the majority of phthalates detected in house dust. The results further indicated that household vacuum dust is a cost-effective alternative to the expensive fresh dust measurements. The results of this study will be used by Health Canada to improve how the Department conducts assessments of Canadians' exposure to phthalates. Results of this research are published in Indoor Air, 2013, 23(6), 506-514.

Mice Exposed In Situ to Urban Air Pollution Exhibit Pulmonary Alterations in Gene Expression in the Lipid Droplet Synthesis Pathways

Health Canada is responsible for assessing the health risks associated with air pollution. Particulate air pollution is produced from combustion sources such as vehicle emissions, cigarette smoke and industrial releases. In this study, Health Canada looked into the precise biological mechanisms by which particles contribute to adverse pulmonary effects, which, to date, are not fully understood. Laboratory mice were housed in cages in Hamilton, Ontario, Canada at a site located 1 km down-wind of two major steel industries, and within 500 meters of a heavily used highway. Mice were either exposed to ambient air or to air from which particles were removed by filtration. The mice were kept in this environment for 3-10 weeks. Once exposure was complete, lung samples were collected to study the mechanisms underlying pulmonary responses to air particles. Following exposure to the ambient air, changes were observed in the levels of a subset of genes involved in the production of lipid droplets. It can be hypothesised that exposure to air pollution triggered the synthesis of lipid droplets in the lungs in order to protect the exposed tissues. This model needs to be investigated in greater detail so that the health implications of prolonged stimulation of lipid droplet synthesis can be better understood. The results of this study will contribute towards Health Canada's ongoing efforts to understand the levels of exposure to air pollution that may lead to adverse health effects in humans and how the cells in the body cope with exposure to air pollution. Results of this research are published in Environmental and Molecular Mutagenesis, 2013, 54(4), 240-249.

The Air Quality Health Index as a Predictor of Emergency Department Visits for Ischemic Stroke in Edmonton, Alberta

Health Canada assisted in the development of the Air Quality Health Index (AQHI), an information tool that helps the public to protect their health by knowing when it is advisable to reduce their exposure to outdoor air pollution. In this study, Health Canada sought to better understand the possible health effects within the general population living in areas with elevated AQHI levels. This study examined whether emergency room visits for acute ischemic stroke were related to a change in AQHI. Data from four years of emergency department (ED) visits in Edmonton, Alberta were linked to local AQHI levels. The results showed that exposure to pollution producing a high AQHI increased the risks of ED visits for strokes during the summer, with seniors more sensitive to AQHI changes. This study determined that there is a relationship between ED visits for strokes and an increase in the AQHI. The results of this study will help Health Canada to better understand how the AQHI can be used as an information tool to inform Canadians about reducing their exposure to outdoor air pollution and possible health risks. Results of this research are published in the Journal of Exposure Science and Environmental Epidemiology, 4 December 2013, doi: 10.1038/jes.2013.82.

A Cohort Study of Intra-Urban Variations in Volatile Organic Compounds and Mortality, Toronto, Canada

Health Canada is responsible for assessing the health risks of air pollution as outlined in the Clean Air Regulatory Agenda. In this study, Health Canada examined whether long term exposure to outdoor levels of volatile organic compounds (VOCs) was related to increased mortality rates in a sample of approximately 60,000 Toronto adults. Study participants were identified from income tax filings in 1982, and deaths among these individuals were identified from a national mortality database. An exposure model for VOCs was created for subjects in Toronto which used variation in VOC exposure across Toronto to determine risk of mortality. The results of the study revealed that while outdoor levels of VOCs, particularly benzene, were associated with an increased risk of cancer mortality; exposure to VOCs did not significantly alter the relationship between traffic related pollution (NO2) and cardiovascular mortality. This study adds to the existing scientific evidence as there have been very few studies that have evaluated associations between VOCs and health outcomes, and few have examined the joint relationship between VOCs and NO2 on health. Health Canada will use the results of this study to assess health risks to Canadians by specifically considering exposure to VOCs as part of a strategy to improve air quality. Results of this research are published in the journal of Environmental Pollution, 2013, 183, 30-39.

Acute Changes in Lung Function Associated with Proximity to a Steel Plant: A Randomized Study

Under the federal Clean Air Regulatory Agenda, Health Canada is responsible for the health risk assessments of air pollution emitted from various industrial sectors, including the iron/steel industry. Currently, there are limited data available on the respiratory effects of exposure to air pollutants emitted from the iron/steel industry. In this study, Health Canada examined the human cardiovascular effects of air pollution near a steel plant, and found that air pollutant levels were higher near the steel plant than at a second site five kilometers away. Moreover, subjects staying near the plant experienced a higher heart rate than when they stayed at the second site. The results of this research suggest that air quality near steel plants may influence cardiovascular physiology. Health Canada will use the results of this study to fill gaps in knowledge in the assessment of health risks related to iron and steel industrial emissions. Results of this research are published in Environment International, 2013, 55, 15-19.

Acute Effects of Ambient Ozone on Mortality in Europe and North America: Results from the APHENA Study

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Ozone is a major component of smog and is produced from the combustion of fossil fuels. Research indicates that on high smog days, more people are admitted to hospitals for heart and lung problems and more people die from heart and lung diseases. In this study, Health Canada compared the effects of ozone on mortality in data from Canada, the United States, and Europe. The number of deaths daily in 12 Canadian cities was collected and related to levels of ozone. The findings suggest that when ozone was higher, there were more deaths. The same type of comparison was initiated for more than 100 cities in the United States and Europe and similar results were found. The results of this study serve to strengthen Health Canada's understanding of how ozone can contribute to mortality and thus help it to determine how to improve air quality in Canada. Results of this research are published in Air Quality, Atmosphere and Health, 2013, 1-9.

Application of the Deletion/Substitution/Addition Algorithm to Selecting Land Use Regression Models for Interpolating Air Pollution Measurements in California

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. In order to understand the effects of exposure to outdoor air pollution on health, estimates of air pollution at locations where people live and work are needed. In this study, Health Canada developed models of exposure for all locations in California using information from satellites, ground data, and land use in these areas. The initial test of this model was conducted on subjects in California due to the richness of the information available. Health Canada will use methods developed in this study to estimate peoples' exposure to pollution and relate these estimates to health in Canada. For example, the methods developed in this study to estimate exposure are currently being used in to estimate exposure to air pollution in the Canadian Census Health and Environment Cohort (CanCHEC), a study of 2.7 million Canadians whose mortality and cancer incidence is being used to assess the effects of exposure to outdoor air pollution. The results of this study will be used by Health Canada to understand how to improve air quality in Canada. Results of this research are published in Atmospheric Environment, 2013, 77, 172-177.

Associations between Ambient Air Pollution and Daily Mortality among Elderly Persons in Montreal, Quebec

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Research suggests that air pollution causes a small increase in mortality within hours or days of exposure. However, information on which groups of people have the greatest risks and the reasons their risks are elevated is limited. In this study, Health Canada in collaboration with researchers from McGill University used data on deaths and use of health care in Montreal from 1984-2003 to determine whether people with certain underlying health conditions have a greater risk of death from air pollution exposure. This information helps us understand how air pollution can adversely affect Canadians and allows us to target improvements in air quality and to communicate risk to those subjects most affected. Results showed that people with diabetes and heart disease had a greater risk of death from air pollution exposure. The results of this study will be used by Health Canada to understand the health impacts of air quality in Canada and may influence how advice on reducing air pollution exposure is targeted. Results of this research are published in Science of the Total Environment, 2013, 463-464, 931-942.

Changing Air Mass Frequencies in Canada: Potential Links and Implications for Human Health

Health Canada is responsible for the assessment and management of health risks associated with Canadians' exposure to environmental hazards, including adverse aspects of changing climate and weather patterns. Although many variables have been studied to understand climate change, a more comprehensive assessment involves the simultaneous consideration of multiple meteorological variables during different times of the day. The current study included the consideration of air-mass types, based on the Synoptic Scale Classification (SSC) system, to identify overall climate scenarios in specific locations across Canada. Following an analysis of long-term air-mass frequency trends, and drawing comparisons of population sizes and climate zones, it was found that the changing air-mass trends are highly dependent on season and climate zone, with an overall increase in moderate air masses and a decrease in polar air masses. Furthermore, in the summertime there is generally an increase in moisture content throughout Canada, consistent with the warming air masses. The rising frequency of moist tropical air masses in six of Canada's ten largest population centres has increased the need for heat adaptation and acclimation for a large majority of the Canadian population. In addition, there have been significant decreases in the frequency of 'transition' days across Canada - i.e., days on which there is a gradual changeover from one weather system to another - an important finding which coincides with research findings in the U.S. The results of this study will be used to fill gaps in knowledge that will help Health Canada to more fully assess the health risks related to climate change in a more comprehensive manner than when only air temperature is considered exclusively. Additionally, these findings will also be useful in guiding Health Canada's future research studies on human health effects related to weather, climate, and air pollution. Results of this research are published in the International Journal of Biometeorology, 2014, 58(2), 121-135.

Comparison of Geostatistical Interpolation and Remote Sensing Techniques for Estimating Long-Term Exposure to Ambient PM2.5 Concentrations Across the Continental United States

Health Canada is responsible for conducting risk assessments on air pollution as part of the Clean Air Regulatory Agenda. Historically, ground data has been used to estimate exposure to outdoor air pollution to Canadians. In this study, Health Canada used and compared satellite and ground data approaches to estimate exposure to outdoor air pollution. Results from this study suggest that data from satellites circumnavigating the Earth can provide exposure information which is more representative of the Canadian population and of equal quality as ground data. As a result of these findings, Health Canada will now regularly use both sources of data to estimate exposure to outdoor air pollution in Canada. Health Canada will use this information to understand how to improve air quality in Canada and the risks of developing long term health problems following exposure. Results of this research are published in the Environmental Health Perspectives, 2012, 120(12), 1727 - 1732.

Canadian House Dust Study: Population-Based Concentrations, Loads and Loading Rates of Arsenic, Cadmium, Chromium, Copper, Nickel, Lead, and Zinc inside Urban Homes

Pollutants from both indoor and outdoor sources may result in adverse impacts on the health of Canadians. Health Canada recently completed a statistically representative national baseline study for metal concentrations in dust sampled from urban households. It looked at the influence of house age, smoking behaviour and urban setting on metal levels in dust. Sampling for this study was conducted between 2007 and 2010 and included measurements for the metals arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in house dust. The study took three types of measurements: concentration of the metal, load (amount of metal per square meter), and loading rate (how fast the metal accumulates in the house). The results of the study provide Health Canada with a better understanding of the background levels of metals that Canadians are routinely exposed to in their homes and how they can be effectively measured in dust. This information will be used to inform future research and risk management activities related to exposures to metals in indoor environments. Results of this research are published in the journal Science of the Total Environment, 2013.

Exposure to Air Pollution near a Steel Plant and Effects on Cardiovascular Physiology: A Randomized Crossover Study

Health Canada conducts health risk assessments, under the federal Clean Air Regulatory Agenda, on air pollution emitted from various industrial sectors. Currently, there are limited data available on the cardiovascular effects resulting from exposure to air pollutants emitted from the iron and steel industry sector. In this study, Health Canada examined how outdoor air pollution, near a steel plant, influenced cardiovascular function of 61 healthy, non-smoking participants (females/male=33/28, median age 22 years). The participants stayed outdoors for 5 consecutive 8-hour days, including a 30-minute mid-day session of moderate intensity exercise, at each of two sites: in a residential area near a steel plant; and another 5 kilometers away at a college campus, with a 9-day break between the two sites. Blood pressure and pulse rate (representing heart rate) were assessed for each participant on a daily basis, including following the 30-minute elliptical session, at each location. Blood vessel function was measured at the site near the plant. Air pollution concentrations were also monitored at both locations. The results of the study revealed that concentrations of ultrafine particles, sulphur dioxide (SO2), nitrogen dioxide (NO2) and carbon monoxide (CO) were 50% to 100% higher at the site near the plant than at the college site with minor differences in temperature, humidity, and concentrations of particulate matter ≤2.5 µm (micrometers) in size (PM2.5) and ozone (O3). Resting blood pressure, and post-exercise blood pressure and heart rate were not significantly different between the two sites. However, participants’ resting heart rate was moderately higher near the steel plant than at the college site, with male participants experiencing the highest heart rate elevation at the plant site.  On days when concentrations of SO2, NO2 and CO were high, heart rate was also elevated. Higher concentration of ultrafine particles was associated with increased blood pressure; higher concentrations of NO2 and CO were associated with decreased blood vessel function; and the presence of SO2 concentration during exercise was associated with increased heart rate. Results from this study suggest that air quality in residential areas near steel plants may influence cardiovascular physiology. These findings will be useful to inform Health Canada’s risk assessors in their evaluation of the health risks of the iron and steel industry. Results of this research were published in the International Journal of Hygiene and Environmental Health (July 30, 2013).

Residential Indoor and Outdoor Coarse Particles and Associated Endotoxin Exposures

Inhalation of course particles, between 2.5 and 10 micrometers in diameter, in air are known to affect respiratory functions of Canadians. Health Canada is working to understand the major sources of exposure to pollutants in indoor and outdoor air. Sources of outdoor coarse particles include windblown dust or sea salt and combustion-related particles, and may also include biological contaminants such as pollen, fungi, and endotoxins. Endotoxins are present within certain types of bacteria and cause an inflammatory response by the body following exposure. This study, published in Atmospheric Environment in collaboration with the Regina Qu’Appelle Health Region, measured residential indoor and outdoor coarse particle concentrations, and associated endotoxin levels, in Regina in 2007. Coarse particle concentrations were found to be higher indoors than outdoors in winter, and higher outdoors in the summer, whereas endotoxin levels were consistently higher outdoors. Significant variability was found between the coarse particle concentrations measured within homes compared with measurements made at centralized monitoring sites within the community. These results will help to refine epidemiology studies which generally use measurements from centralized monitoring sites as a substitute for personal exposure measurements. For more information, please consult Atmospheric Environment, Volume 45, Issue 39, December 2011, 7064–7071.

Urinary Polycyclic Aromatic Hydrocarbons as a Biomarker of Exposure to PAHS in Air: A Pilot Study among Pregnant Women

Exposure to polycyclic aromatic hydrocarbons (PAHs), formed through incomplete combustion and found in the emissions expelled by vehicles, industry, fireplaces, barbeques, candle burning, tobacco smoke, etc., have been linked to adverse health and pregnancy outcomes. Health Canada is working to better understand sources of PAH exposure. In particular, this study followed a group of 19 pregnant women, a segment of the population that may be more vulnerable to the health effects of air pollution. Participants were living in homes where air pollution levels were classed as either “high” (urban/close to industry) or “low” (sub-urban) in Hamilton, Ontario. PAH concentrations were measured in personal, indoor and outdoor air and through the analyses of markers of PAHs in the participants’ urine. Results indicate that exposure to heavy molecular weight PAHs is related to outdoor sources of PAHs (e.g. vehicles, industry), while lighter molecular weight PAHs were related to indoor sources (e.g. candle burning) and exposure to tobacco smoke. Living in “high” pollution areas of Hamilton resulted in higher personal exposure to PAHs compared to living in the “low” air pollution areas. The results suggest that centralized air pollution monitoring sites may be useful in estimating exposure to heavy molecular weight PAHs, but they may not adequately predict personal exposure to lighter molecular weight PAHs. As the first study on PAHs to measure these chemicals in pregnant women, the knowledge gained from this study can be used in future work to more accurately predict PAH exposure and the associated population health effects. Results of the research are published in the Journal of Exposure Science and Environmental Epidemiology, 2012 Jan-Feb;22(1):70-81.

Traffic-Related Air Pollution and Acute Changes in Heart Rate Variability and Respiratory Function in Urban Cyclists

Health Canada is working to understand the short-term health effects of air pollution in a variety of situations, including those related to cycling in high traffic areas. During the summer of 2010, Health Canada conducted a study in Ottawa, Ontario to examine the impact of air pollution exposure on short-term changes in lung and heart function among healthy cyclists. Forty-two healthy adults (19 to 58 years of age) cycled for 1 hour on high- and low-traffic routes, as well as indoors. Traffic-related air pollutants were measured along each cycling route and health measures, including lung function and heart rate variability, were collected before and after cycling. Air pollution exposures were significantly increased when cycling on the high-traffic route compared to the low-traffic route. While air pollution exposures did not have a significant impact on lung function in healthy cyclists, nitrogen dioxide, ozone, and ultrafine particle levels (very small particles, less than 100 nanometres, produced by vehicle emissions) appeared to have an important impact on the biological systems that regulate heart rate. The results of this study suggest that exposure to traffic-related air pollution may result in short-term changes to the biological systems that regulate the heart. This research may inform the advice Health Canada provides to Canadians to reduce their risks from the effects of air pollution. Results of the research are published in Environmental Health Perspectives, 2011 Oct: 119(10): 1373-8.

Windsor, Ontario Exposure Assessment Study: Design and Methods Validation of Personal, Indoor and Outdoor Air Pollution Monitoring

Air pollutants from both indoor and outdoor sources may result in adverse impacts on the health of Canadians. The activities that Canadians choose to engage in, and the indoor and outdoor air pollutant concentrations, impact personal exposure levels to air pollution. Health Canada, in partnership with the University of Windsor, undertook a study in Windsor, Ontario to investigate personal levels of air pollution exposure. This study investigated the contribution of air pollution from indoor and outdoor sources on the personal exposure of both adults and asthmatic children, and assessed the impacts of air pollution exposure on the respiratory health of the children included in the study. In total, 50 adults and 51 asthmatic children participated in the study, which took place over 5 consecutive days in both the summer and winter. Indoor, outdoor and personal monitoring was conducted for a number of pollutants. The asthmatic children’s respiratory health was assessed, and each child kept a diary of their respiratory symptoms over the study period. Analyses of the relationships between air pollution monitoring, respiratory health and personal exposure data collected from this study are underway. Results from this study will improve our understanding of the relative health impacts of indoor and outdoor sources of air pollution and inform the development of actions to reduce the health risks Canadians can experience from air pollution. Results of this research, study design and methods are published in the Journal of the Air and Waste Management Association (March 2011), 61(3):324-338.

Back-Extrapolation of Estimates of Exposure from Current Land-Use Regression Models

Air pollution concentrations can be affected by a number of factors, including geographic locale, limiting the applicability of centralized monitoring site data to estimate personal exposure. Health Canada is working to understand these differences and improve the prediction of air pollution exposures within different urban areas. In this study, Health Canada, in collaboration with McGill University, applied land-use regression modelling, which uses pollutant monitoring data along with land-use information such as traffic volume, distance to industrial sources, distance to ports and harbours, and housing and population density, to better predict air pollution exposure throughout an urban area. Health Canada investigated three new methods that used land-use regression models to predict past air pollution exposure. To start, nitrogen dioxide (NO2) levels in Montreal were measured at 130 locations over three two-week periods in 2005 and 2006. This information, along with fixed site monitoring data, land-use and traffic data were used to develop a current land-use regression model for Montreal. Next, historic data on land-use and traffic were used to develop models for time periods that were 10 and 20 years in the past using three different techniques. These models were used to estimate air pollution exposure for subjects involved in a 1996 study of postmenopausal breast cancer. The analyses from the 2006 and the three historic models demonstrated similar levels of elevated risk of postmenopausal breast cancer associated with increased exposure to nitrogen dioxide. As this research is some of the first to investigate the use of land-use regression modelling to back-predict air pollution exposure, further analyses will be required to evaluate the accuracy of the different techniques. Land-use regression modelling is a valuable tool to estimate air pollution exposure and, it can be used to predict historic exposure levels. This work is important to improving understanding of the impacts of long-term exposure to air pollution on the health of Canadians. Results of this research are published in Atmospheric Environment (November 2010), 44(35): 4346-4354

Evaluation of Land-Use Regression Models Used to Predict Air Quality Concentrations in an Urban Area

Estimating exposure to air pollution within Canadian cities is important to understanding the long-term impacts of air pollution on the health of Canadians. However, air pollution levels within a city can vary greatly depending on geographic location. This Health Canada project, undertaken in collaboration with the U.S. Environmental Protection Agency, evaluated the ability of land-use regression models to predict air quality concentrations across an urban environment. Land-use regression modelling uses pollutant monitoring data along with land-use information, such as traffic volume, distance to industrial sources, distance to ports and harbours, as well as housing and population density, to better predict air pollution exposure throughout an urban area. In this work, regional air quality models were used to predict air pollutant levels in New Haven, Connecticut. Subsets of the modelled air quality data (from between 25 and 285 specific locations), along with land-use data, were used to develop land-use regression models for the city. A comparison between the land-use regression model’s performance at independent test locations indicated that as the number of locations used to develop the regression model increased, the accuracy increased. Results suggest that air quality modelling results could be used to inform the development of land-use regression models and improve their performance. This work supports Health Canada’s ability to better predict air pollutant exposure through the development of more accurate land-use regression models. Results of this research are published in Atmospheric Environment (September 2010), 44(30): 3660-3668.

Buoyancy-Corrected Gravimetric Analysis of Lightly Loaded Filters

Particulate matter in the air may result in adverse impacts on the respiratory health of Canadians. Accurate measurements of particulate matter help Health Canada to evaluate the potential for adverse health effects caused by exposure to environmental releases of particulate matter, e.g. from industrial and automobile emissions. In this study, Health Canada used its patented Archimedes M3TM weighing facility (see US Patent 7357045) to develop a method to more accurately measure particulate matter and better understand how environmental factors contribute to measurement errors. For example, when very small samples (<100 micrograms) of particulate matter are being weighed, measurement errors associated with changes in environmental conditions (i.e. temperature, relative humidity, and air density) are more significant. The results of this research, published in the Journal of the Air & Waste Management Association, have enabled Health Canada to develop a method to overcome these challenges. Future research will be directed towards development of guidelines for gravimetric analysis of nanoparticles and other low mass samples of airborne particulate matter such as personal and indoor exposure samples. Ultimately, this research will strengthen Health Canada’s ability to perform toxicological risk assessments. For more information, please consult the Journal of the Air & Waste Management Association, 2010 Sep; 60(9):1065-77.

Concentration Distribution and Bioaccessibility of Trace Elements in Nano and Fine Urban Airborne Particulate Matter: Influence of Particle Size

Particulate matter in the air may result in adverse impacts on the respiratory health of Canadians. Health Canada is working to understand the major sources of exposure to particulate matter and which components of particulate matter are of greatest health risk. In this study, Health Canada used highly sensitive measurement technologies to evaluate particulate matter in Ottawa’s urban air. Researchers separated the components of the particulate matter using a device which categorizes particulate matter according to size. From smallest to largest, the categories included: nanoparticles (less than 100 nanometres, also called “ultrafine particles”); fine particles (100 nanometres to 1 micrometre); and coarse particles (1 to 10 micrometres). The mass and components of the particulate matter were determined using an extremely sensitive weighing facility (Archimedes M3TM, see  US Patent 7357045) and mass spectrometry analysis, respectively. Health Canada found that the elements vanadium (V), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), selenium (Se) and cadmium (Cd) tended to be more concentrated in the nanoparticle-size fraction. Other elements, including iron (Fe), strontium (Sr), molybdenum (Mo), tin (Sn), antimony (Sb), barium (Ba) and lead (Pb), were more concentrated in the fine-particle fraction. Results suggested that motorized vehicles were a major contributor to the composition of these urban particulate matter samples. Application of these technologies will be useful to inform motor vehicle emission level and fuel additive guidelines. Results of this research are published in the Journal of Water, Air and Soil Pollution, Volume 213, Numbers 1-4, 211-225.

Hepatic mRNA, microRNA, and miR-34a-Target Responses in Mice after 28 Exposure to Doses of Benzo(a)pyrene that Elicit DNA Damage and Mutation

As part of the Chemicals Management Plan, Health Canada conducts research on chemicals in support of its mandate to assess the risks of various substances to Canadians. Benzo(a)pyrene (BaP) is an environmental toxin that has been shown to cause cancer and DNA mutation in laboratory animals. As a result of the extensive published information available on the effects of BaP, it also serves as an excellent model for the development of new methodologies to study toxicity because one can compare existing and new methods directly. Toxicogenomics is a relatively new discipline that investigates the effects of exposure to chemicals on all of the genes within an organism, by examining what genes are turned on and off by the chemical.

In an effort to better understand the toxicology of BaP and to explore the potential application of toxicogenomics to the risk assessment of BaP, groups of male mice were treated with varying concentrations of BaP for 28 days. BaP exposure resulted in 134 genes (of 40,000) that were statistically significantly altered in the liver. These genes were primarily involved in the metabolism of BaP, the response to DNA damage, and how cells divide and replicate. This finding is consistent with previous research investigations. The results of the study provide important information on the genes and mechanisms involved in the response of the liver to BaP exposure across a range of doses. The gene changes measured are highly aligned with observed molecular changes, supporting the use of toxicogenomics as a tool to predict toxicity. These results will also be used to help determine how toxicogenomics data can best support risk assessments at Health Canada. Results of this study were published in the Environ Mol Mutagen. 2012 Jan;53(1):10-21.

Spatial Distribution of Polycyclic Aromatic Hydrocarbons (Pahs) in an Urban Environment

Exposure to polycyclic aromatic hydrocarbons (PAHs), formed through incomplete combustion and found in the emissions expelled by vehicles, industry, fireplaces, barbeques, candle burning, tobacco smoke, etc., has been linked to health effects including adverse pregnancy outcomes. Estimating exposure to PAHs within Canadian cities is important to understanding the long-term impacts of these compounds on the health of Canadians. However, air pollution levels within a city can vary greatly depending on geographic location. Health Canada, in collaboration with Carleton University, undertook this study in Hamilton, Ontario, to better understand the spatial distribution of PAHs and fine particulate matter, another air pollutant linked to health impacts, by measuring outdoor air concentrations. Air pollution levels were measured in two seasons, winter and summer of 2009 at approximately 50 locations across the city of Hamilton. This study found that outdoor fine particulate matter and PAH concentrations were greater below the Niagara escarpment, which runs through the city and bisects it into lower and upper regions. The difference in PAH concentrations between the area below the escarpment and that above it was much greater than for fine particulate matter in both summer and winter. Elevated levels of both pollutants were observed to occur near or downwind of the central business district and industrialized harbourfront area, suggesting the contribution of local sources. The PAH levels also exhibited a greater degree of variability than the fine particulate matter both above and below the escarpment. This study is one of the first to measure PAHs on such a local scale across a city in two seasons. The knowledge gained from this study can be used in future work to more accurately predict PAH exposure and the associated population health effects. Results of this research are published in Atmospheric Environmental 59 (2012) 272-283 (on-line May 2012).

Note this is available in final form on-line which will be the November 2012 issue.

Germline Mutation Rates in Mice Following in Utero Exposure to Diesel Exhaust Particles by Maternal Inhalation

Particulate air pollution is widespread in many urban environments and Health Canada is responsible for working to ensure that accurate information on the health risks from pollution is available to all Canadians, and acting to reduce these health risks as much as possible. One source of particulate air pollution is diesel exhaust particles (DEPs) from engines. In order to better understand the impacts of exposure to particulate air pollution on human health during development, Health Canada conducted this study to investigate mutations in the germ cells (sperm and eggs) of mice that were exposed to DEPs while they were in their mother’s uterus (in utero). Mutations in the DNA of germ cells are particularly important to understand because they can be passed on to offspring and can result in harmful effects, such as heritable diseases, developmental effects and cancers. Pregnant mothers were exposed to DEPs suspended in air. Their offspring were born, raised to maturity, and then mated with unexposed animals to produce litters of their own. A 2-fold increase in the mutation rate was found in the mice whose fathers had been exposed in utero. These results support previous findings that DEPs cause mutations in reproductive cells. There was also an increase in the number of mutations in the DNA contributed by mothers who were never exposed, when producing offspring with an exposed male. This result suggests that mutations in the sperm of the exposed male can also cause indirect effects on the DNA coming from the egg of an unexposed female at the time of conception. Overall, these results demonstrate that exposing mice to inhaled DEPs during their development in utero produced mutations in germ cells that could subsequently be transmitted to their offspring and this knowledge may help Health Canada protect the health of vulnerable populations. This study was conducted in collaboration with the Danish National Research Centre for the Working Environment and was published in Mutation Research (2011 Jul 1), 712(1-2):55-58.

Physical-Chemical and Microbiological Characterization, and Mutagenic Activity of Airborne Pm Sampled in A Biomass-Fueled Electrical Production Facility

Many areas of the world, including parts of Canada, employ the combustion of biomass (e.g., wood, agricultural waste, animal waste, etc.) to produce heat and electric power. Transportation, handling and combustion of plant biomass (e.g., straw, wood chips) can result in the generation of airborne particulate material (PM) and occupational exposure to airborne particles, which may contribute to adverse health effects that are important for Health Canada to understand. To better understand the potential health effects resulting from the combustion of biomass for heat and electricity, Health Canada conducted this study to examine airborne PM at a biomass-fuelled electric power generation facility in Denmark. The PM was analysed for chemical contaminants such as toxic metals and polycyclic aromatic hydrocarbons (PAHs), as well as its ability to generate reactive oxygen species (ROS) in a liquid suspension and induce genetic mutations in a bacteria test system. The results showed that PM derived from combusted biomass collected from the boiler room and the biomass storage hall had higher levels of chemical contamination, a higher potential to induce the formation of ROS, and a greater ability to induce genetic mutations in bacteria. Additional analyses investigated the properties of dust particles generated by agitating the biomass fuel (i.e., straw or wood chips). The results showed low levels of contamination, and a relatively low potential to induce adverse health effects. Nevertheless, microbiological analyses did show high concentrations of fungi and bacterial endotoxins (i.e., toxins generated by bacteria) in the dust generated by biomass agitation. The results indicate that exposure to the PM present in the boiler room and biomass storage area may contribute to an elevated risk of adverse health effects which may be useful to inform regulatory approaches. This study took place in collaboration with the Danish National Research Centre for the Working Environment and the Geological Survey of Denmark and Greenland and was published in Environmental and Molecular Mutagenesis (2011 May), 52(4):319-330.

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