Investigation of spatial and seasonal variations of antropogenic and biogenic volatile organic carbons (VOCs) determined by thermal desorption GC-MS technique and contribution of biogenic VOCs to ozone concentrations at high altitude semi-rural site

The ambient air contains a group of pollutants called volatile organic compounds. Some of them have been the subject of most of the research due to their negative effects on the environment and health. In this study, it was aimed to collect and evaluate a total of 70 volatile organic compounds (biogenic and anthropogenic origin) in Bolu atmosphere. Passive and active sampling techniques were performed. The passive sampling was carried out at 47 sampling points during the winter (28 January 2017 - 12 February 2017) and 63 sampling points in the summer (7 July 2017 - 23 July 2017). At our station in the university campus, 68 compounds for every month between April - November 2017; January 2018 and 70 compounds for every month between April - August 2018 were collected with active sampling in daily and 6-hour periods. Analyses were performed using a thermal desorption gas chromatography-mass spectroscopy system. The results have been compared with similar studies around the world. It is valuable to be able to identify the mechanisms, atmospheric roles and sources of these compounds as well as determine their atmospheric concentrations. For this purpose, the time-dependent changes of the compounds, their relations with meteorological factors and the correlations between each other were examined. Especially, the ozone formation potential of volatile organic compounds and the effective factors in the formation have been investigated. Pollutant distribution maps were plotted and thus, source regions were determined for each compound. Source apportionment was carried out with Positive Matrix Factorization. The studies had shown that biogenic sources were the predominant source for volatile organic compounds in the region.