Secondary organic aerosol formation from aromatic and biogenic hydrocarbons.

Abstract

The tropospheric oxidn. of hydrocarbons by ozone or OH or NO3 radicals leads to the formation of condensable products that can undergo gas-to-particle conversion. We studied the aerosol formation from m-xylene, 1,2,4-trimethylbenzene, and several biogenics (mono- and sesquiterpenes as well as oxygenated compds.) in a series of outdoor smog chamber expts. Expressions for the fractional secondary org. aerosol (SOA) yield (Y) are developed within the framework of a gas/partitioning absorption model, and the yield is a function of the org. aerosol mass concn. The observations not only suggest that yields for individual hydrocarbons are additive but that smog chamber SOA yield data may be extrapolated to the ambient atm. [on SciFinder (R)]