PRODUCTION AND DISTRIBUTION OF ORGANIC NITRATES, AND THEIR RELATIONSHIP TO CARBONYL-COMPOUNDS IN AN URBAN-ENVIRONMENT

As part of the PACIFIC '93 field study, measurements of a series of hy drocarbon oxidation products, specifically 12 alkyl nitrates, six hydr oxy nitrates and the carbonyl compounds propanal, acetone, butanal and methyl ethyl ketone, were quantitatively determined in atmospheric sa mples in a suburban environment downwind of the city of Vancouver, BC. In this study we found that the hydroxy nitrates represent a substant ial fraction of the total measured organic nitrates. In addition, seve ral unidentified organic nitrates were found to contribute up to 38% ( 215 pptv) to the total quantity of organic nitrates during the daytime maximum. The relationship between the alkyl nitrates and the correspo nding carbonyl compounds indicates that up to 90% of the carbonyl comp ounds measured are produced from sources other than the precursor alko xy radical of the same carbon number. These sources are believed to be the decomposition of larger alkoxy radicals, or direct anthroprogenic /biogenic emissions. (C) 1997 Elsevier Science Ltd.