Detection of Air Pollutants in the Lower Fraser Valley by Fourier Transform Infrared Spectroscopy

The Trent experiment was part of Environment Canada's Pacific 2001 Air Quality Study which took place in August 2001. The Lower Fraser Valley area is of particular interest to study as it experiences emissions from urban, suburban, marine and agricultural sources, thereby making it one of Canada's "smog corridors". The population of the Lower Fraser Valley is predicted to increase and therefore the emissions of pollutants are expected to increase as well. The purpose of the Pacific 2001 study was to investigate the changes in size and composition of aerosols and gases in the smog. During the study, air and ground measurements were taken at 5 locations in the greater Vancouver area. The purpose of the Trent experiment was to use Fourier Transform spectroscopy to measure the concentrations of O₃, CO, CO₂, N₂O and CH₄ along an open path at ground with a BOMEM DA-8 FTS. The measurements for this experiment were taken at the Langley School site from August 14, 2001 until September 1, 2001; approximately 5 long path measurements were taken daily. The concentrations of CO, CO₂, N₂O and CH₄ varied throughout the study in August. The concentration of CO varies strongly because CO has a short lifetime and the concentration can increase rapidly due to large anthropogenic pollution sources, such as automobile use. The other three species, CO₂, N₂O and CH₄, have much longer lifetimes and thus are more stable in the troposphere; the concentrations of these species did not vary greatly throughout the study. Ozone and ammonia concentrations were also measured. A second FTS was flown on the Convair 580 aircraft viewing in the nadir direction to determine column amounts of ozone and CO.