Airborne lidar measurements of aerosol and ozone above the Canadian oil sands region

Aircraft based lidar measurements of atmospheric aerosol and ozone were conducted to study air pollution from the oil sands extraction industry in northern Alberta. Significant amounts of aerosol were observed in the polluted air within the surface boundary layer, up to heights of 1 km to 1.5 km above ground. The ozone mixing ratio measured in the polluted boundary layer air was equal to or less than the background ozone mixing ratio, in the range of 10 ppbv to 35 ppbv. On one of the flights, the lidar measurements detected a layer of forest fire smoke above the surface boundary layer in which the ozone mixing ratio had a maximum value of 70 ppbv. Measurements of the linear depolarization ratio in the aerosol backscatter were obtained with a ground based lidar and this aided in the discrimination between the separate emission sources from industry and forest fires. The retrieval of ozone abundance from the lidar measurements required the development of a method to account for the interference from the substantial aerosol content within the surface boundary layer.