EMISSION RATIOS AND PHOTOCHEMICAL PRODUCTION EFFICIENCIES OF NITROGEN-OXIDES, KETONES, AND ALDEHYDES IN THE LOWER FRASER VALLEY DURING THE SUMMER PACIFIC-1993 OXIDANT STUDY

Observations made at a ground site east of Vancouver, Canada, were use d in a principal component analysis (PCA) to derive (1) the emission r atios (ER) SO2, NOx, HNO2, HNO3, ketones, and aldehydes relative to CO and (2) the photochemical production efficiencies (PPE) of O-3, HNO2, HNO3, PAN, and several ketones and aldehydes relative to the formatio n of NOz. It is shown that derived ER(SO2) and ER(NOx) are consistent with the mobile emission sources in the Greater Vancouver Regional Dis trict (GVRD) emission inventory. Combining the ER data for other speci es with the GVRD CO emission inventory, the daily emission rates for t hese species have been estimated, indicating significant sources for t hese species. The derived PPE values for O-3, HNO2, HNO3, PAN, the ket ones, and the aldehydes are as follows: PPE(O-3) is approximately 8-11 depending on the time of day; PPE(acetone) is between 1 and 2; PPE(MV K), PPE(MACR), and PPE(MEK) are approximately the same between 0.1 and 0.2; PPE(HCHO) is between 1 and 2, but PPE(propanal) and PPE(butanal) are lower than PPE(HCHO) by a factor of 2-10. It is shown that the da ily photochemical production rates of O-3 and the carbonyl species are approximately linear functions of the NOx daily emission rates. When the photochemical production rates are compared with counterpart daily emission rates, it is shown that for the organic compounds, the contr ibutions from photochemistry were more important than daytime emission s; for HNO2, there is more emission contribution than photochemistry, opposite to the case for HNO3. (C) 1997 Elsevier Science Ltd.