Natural and Anthropogenic Sources of Organic Aerosol in the Atmosphere: Kinetics and Mechanism of Formation in the Forest-steppe Zone of West Siberia

Contribution of carbonyl compounds into the generation of atmospheric organic aerosol in the presence of typical urban air pollutants is investigated. Aldehydes and ketones entering the atmosphere from natural and anthropogenic sources are identified by means of high-performance liquid chromatography. Field measurements were carried out on the territory of Novosibirsk scientific center and in adjacent forest areas. It is shown that the transport of typical gaseous urban air pollutants (nitrogen oxides and ozone) into the air of forest areas and the transport of biogenic compounds (alkenes and aldehydes) to the urban territory cause sharp changes of the kinetics and mechanism of organic aerosol generation in comparison with the processes taking place in typical urban atmosphere. Thus, in the presence of ozone, the yield of aerosol products from formaldehyde, acetaldehyde, and propanal photonucleation increases by a factor of 4–8, while for benzaldehyde and acrolein it exhibits 5- and 30-fold decrease, respectively. For aromatic substituted aldehydes and furfural, aerosol yield slightly increases (only up to 30%). The results make it possible to carry out quantitative evaluation of the capacity of natural and anthropogenic sources of organic aerosol in the forest-steppe zone of Western Siberia and predict the biological effect of aerosol generated in the presence of various pollutants.