Determination of volatile organic compounds in the atmosphere and their influence on ozone formation

The elevated levels of various atmospheric pollutants as a result of anthropogenic processes, their transformations, impacts on human population, landscape receptors as well as the simulation of their transport in the atmosphere were addressed in the project in frames of which three complex sampling campaigns (2001-2003) were performed at three sites of the Czech Republic with various levels of contamination. Air and aerosol samples for subsequent chemical analysis were collected at three sites during 5-10 summer days each year. A scale of organic pollutants - carbonyls, semi-volatile organic compounds (in separate fractions - acidic, basic and neutral) and volatile organic compounds (VOC) - was analyzed besides inorganic pollutants and ozone concentration. Results of VOC measurements from 2003 campaign are presented here. A preliminary study was performed at all sites focused on the determination of biogenic emission sources and their contribution to local tropospheric ozone production. The Incremental Reactivity method was used for calculations. The total VOC contribution to local ozone production varied between 4.7 and 8.6 mu g m(-3), the fractions of biogenic hydrocarbons, anthropogenic hydrocarbons and carbonyl compounds varied from 29 to 44%, from 23 to 55%, and from 16 to 34%, respectively.