Anthropogenic influence on biogenic secondary organic aerosol

Abstract. Because of the climate and air quality effects of organic aerosol, it is important to quantify the influence of anthropogenic emissions on the aerosol burden, both globally and regionally, and both in terms of mass and number. Methods exist with which the fractions of organic aerosol resulting directly from anthropogenic and biogenic processes can be estimated. However, until now, the possible anthropogenic enhancement of secondary organic aerosol formation from naturally emitted precursors has not been explicitly accounted for. Here, we describe the mechanisms through which such an effect may occur and suggest methods suitable to detect it in measurements. An examination of published data reveals qualitative support for the existence of the enhancement effect.