Contribution of primary aerosol emissions from vegetation‐derived sources to fine particle concentrations in Los Angeles

Field measurements of the n ‐alkanes present in fine atmospheric aerosols show a predominance of odd carbon numbered higher molecular weight homologues (C 27 –C 33 ) that is characteristic of plant waxes. Utilizing a local leaf wax n ‐alkane profile in conjunction with an air quality model, it is estimated that, at most, 0.2–1.0 μg m −3 of the airborne fine particulate matter ( d p < 2.1 μm) present in the Los Angeles basin could originate from urban vegetative detritus; this corresponds to approximately 1–3% of the total ambient fine aerosol burden. However, some of the observed vegetation aerosol fingerprint in the Los Angeles air may be due in part to emissions from food cooking rather than plant detritus. Seasonal trends in the ambient n ‐alkane patterns are examined to seek further insight into the relative importance of anthropogenic versus natural sources of vegetation‐derived fine particulate matter.