Determination of Diurnal Cycles of Acrolein and Other Small Carbonyls in Regions Impacted by Vehicle Emissions; Final rept

摘要

The objective of this research was to determine the diurnal cycles of acrolein and other carbonyls in both summer and winter. The test site was the Air Resources Board monitoring station at North Sunrise Blvd in Roseville, California since this site is located near several large roadways that were suspected sources of acrolein and it is impacted by high ozone concentrations in the summer that would facilitate the photochemical production of oxidized hydrocarbons. The results showed that different carbonyl chemicals showed different patterns based on their most likely sources. In the summer, acrolein did not correlate with ozone or traffic patterns, which was unexpected based on the common assumptions about the sources of acrolein. In winter, the acrolein showed a clear diurnal cycle with a peak concentration in the evening that correlated very well with a wood smoke tracer. Therefore, it appears that wood smoke was the dominant source of acrolein in winter. Most of the chemicals that were routinely detected could be ascribed to a specific source such as photochemical generation (glyoxal, glycolaldehyde), wood smoke (2-furaldehyde), transport from the Sierra Nevada Mountains (pinonaldehyde) or direct vehicle emissions (tolualdehydes). Surprisingly, primary vehicle emissions seemed to contribute few carbonyls at this site that was located to detect vehicle emissions.