Air Quality Health Index classroom kit, grades 5 and 6, environment: chapter 12
Particulate matter (PM)
PM10 collects in the nose and throat. The body tries to get rid of PM10 by sneezing and coughing.
PM2.5 is so light that it can travel deep into lungs through the trachea and bronchi. It collects in tiny air sacs (alveoli) where oxygen enters the bloodstream. This can cause coughing or wheezing and long-term illnesses. PM2.5 also contains harmful chemicals. These chemicals are delivered straight to our blood through our respiratory system.
- Map out the path of PM through the respiratory system.
See how air pollution moves around
Orange dye and water can help us understand air pollution. Imagine pouring a litre of orange dye into the ocean. The color will stay for a few seconds. As soon as the waves come, the orange dye will be mixed with the water in the huge ocean. It’s not just the amount of water that dilutes the dye, it’s also the mixing by the waves.
Now think of pouring the same amount of orange dye into a bathtub. The bath water will turn very orange. The orange color won’t be washed away because it’s trapped in the bathtub, in a small amount of water, and there can be no mixing with clean water.
You can try this on a smaller scale using eye droppers, glass bottles, and buckets. Think about how you can make the simulation.
If air pollutants are in a large area with good airflow, they will mix with the air. Then they quickly separate and go in different directions, like the orange dye in the ocean.
However, pollutants can build up or be trapped in an area and build up, just like the dye in the bathtub. This can happen when there is no wind, the weather is calm and pollution stays in one place. It can also happen when hills and valleys trap pollutants. The outcome is poor air quality. That is why the Air Quality Health Index (AQHI)can be higher in towns or cities that are surrounded by hills or mountains.
Air quality can improve during precipitation. Rain can “wash” pollution out of the sky. This is sometimes called “rainout”. In fact, when it is sunny and warm outside with fairly light winds, the air quality is often worse than when it is raining. This is because the ultraviolet from the sun is needed for one of the chemical reactions for ground-level ozone. The direction of the wind also plays a big role in long-range transportation of air pollution and the resulting AQHI.
- A polluting town located on a hill consistently claims that its high emissions are not causing air quality problems. The town mayor claims:
“Once the pollutants are diluted by the weather and carried away from the site of production, they are no longer a problem. We measured our air quality last week and it was fine.”
You are scheduled to speak at a community meeting in the town because air quality is a major problem where you live. Since this is quite far away, the mayor doesn’t think it matters what you say. Write speaking notes for the meeting with the town’s mayor. You must support your statements with scientific facts.
Could you label this diagram to show PM2.5 and PM10 in the respiratory system?
Rain can “wash” pollution out of the sky, but where does it go?
What is it called when the dye goes from a higher concentration (the dish) to a lower concentration (the ocean or tub)?
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