Saskatoon, August 18, 2004 - Scientists from Environment Canada, the Canadian Space Agency, the University of Toronto, York University and the University of Waterloo will be launching one large research balloon and a series of smaller balloons in an intensive study of the ozone layer over Canada this August. The large balloon will carry an instrument package nearly 40 km high in the atmosphere, passing through most of the ozone layer in the earth’s stratosphere as part of the MANTRA (Middle Atmosphere Nitrogen TRend Assessment) research project. The payload on board the MANTRA ballon is comprised of 11 instruments, including an ozone-measuring instrument called MAESTRO (Measurements of Aerosol Extinction in the Stratospheric and Troposphere Retrieved by Occultation), which was developed in 2002 by Environment Canada. The original MAESTRO instrument was launched into space in 2003, on board a Canadian science satellite, and is now measuring the ozone layer from space. The balloon-borne version of MAESTRO, and some of the other instruments that are part of the balloon payload, will take readings as the satellite passes which will serve to verify the accuracy of the measurements made from the satellite. The primary balloon is as tall as a 25-storey building and will carry a payload of over one half tonne. Instrument packages will record the thickness of the ozone layer and measure CFCs and other ozone-depleting substances in the atmosphere. Scientists will compare these readings to measurements recorded by balloon flights over Saskatchewan over the past 20 years. This study will help researchers monitor the effectiveness of measures to reduce ozone-depleting chemicals undertaken since the Montreal Protocol, a global agreement to protect the ozone layer. The extent of global ozone depletion is a cause of concern among scientists, because it is still larger than predicted by the research that formed the scientific basis for the Montreal Protocol and its subsequent amendments. For further information on balloon research, visit this website: http://www.msc.ec.gc.ca/research/balloon/index_e.html NOTE: Three types of research balloons will be used: The giant research balloon, (height: 80m when inflated, payload: 630kg) will be launched only once, between August 20 and September 5, at night. A somewhat smaller balloon will be launched to make measurements of bromine oxide using an instrument from the CNRS in France called Système D'Analyse par Observations Zénithales (SAOZ). The instrument weighs about 20 kg. This flight will be made near sunrise or sunset when the sun is low on the horizon. Much smaller “ozonesonde” balloons (height: 8m when inflated, payload: 3kg) will be launched approximately every other day from August 9 to after the main MANTRA flight , weather permitting, during daylight hours.. Event: Site visits Date: August 20 to September 5, 2004 Location: Vanscoy (the old Air Base - 30 km South West of Saskatoon, Saskatchewan) For more information, please contact: Kari Brintnell Environment Canada, Communications Directorate, Toronto. Tel.: (416) 739-4969 Fax: (416) 739-4380 For on-site details, arranging on-site visits or after hours calls: Tom McElroy Environment Canada, Ozone Scientist Tel.: (306) 242-7588 (at Vanscoy air base) • Please call to confirm details before visiting the site. Carole Duval Media Relations and Information Services Canadian Space Agency Telephone: (450) 926-4972