Polycyclic aromatic hydrocarbons in Los Angeles air from samples collected on teflon, glass and quartz filters

Abstract

Levels of ambient particulate polycyclic aromatic hydrocarbons (PAH) have been measured at seven locations in the Los Angeles area using quartz, glass and Teflon filters operated in parallel at the same sampling face velocities. Daytime and night-time samples (12 h each) were collected during summer and winter. Thirteen PAH, from anthracene to coronene, were quantitated in these samples. The measured concentrations (e.g. mean values of 1.62, 0.97, 0.64 and 3.6 ng m −3 for pyrene, chrysene, benzo(a)pyrene and coronene, respectively) suggest that PAH levels in Los Angeles air have not significantly changed during the last decade. For all but one PAH, concentrations measured on glass and quartz filters were lower in 85–90 % of the total number of observations than those measured in samples collected on Teflon filters. On average, glass/Teflon and quartz/Teflon ratios ranged from 0.25 for pyrene to 0.80 for coronene. These observations are of concern since virtually all information available to date concerning airborne PAH has been derived from samples collected on glass filters.