Gaseous Chemical Characterization of the Lower Fraser Valley Airshed During Pacific 2001
Abstract
During the Pacific 2001 field campaign, measurements of a number of gaseous chemical compounds were made at three different locations: Langley (agricultural), Sumas Mtn (forested, 300 m elev.) and Slocan (urban Vancouver). NOx was the dominant component of NOy and limited conversion to its oxidation products of HNO3 and PAN resulted in low O3 production efficiencies. The sum of the individual measured species (NOyi) show that approximately 17 and 6 percent of the NOy is unaccounted for at Langley and Sumas respectively. Using species indicator ratios, conditions were NOx-limited at Langley and Sumas, whereas, at Slocan, VOC-limited chemistry characteristic of urban environments existed. A secondary nighttime peak in HNO3 at Sumas was, at times, coincident with peaks in HONO, particle nitrate (MOUDI impactor), O3, HCHO and PAN. This behaviour is attributed to return valley flow, but evidence suggests that the formation of HNO3 at night through N2O5 hydrolysis may also be significant.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.A71A0069H
- Keywords:
-
- 0305 Aerosols and particles (0345;
- 4801);
- 0345 Pollution: urban and regional (0305);
- 0365 Troposphere: composition and chemistry