Investigation of particulate matter (PM) samples collected in bolu city center in terms of bio-aerosols and other pollutants and assessment of their correlations with atmospheric visibility range

Particulate matter (PM) in the atmosphere and bio-aerosols, which constitute a significant part of particulate matter, have negative effects on human health and the environment. In addition, PM and bio-aerosols have a direct effect on the climate by scattering and absorbing sunlight, as well as indirectly affecting the climate by forming cloud condensation nuclei and ice nuclei. PM in the atmosphere also causes a decrease in visibility, which adeversely affects human health, land, air and sea transportation and telecommunications. This study has three purposes; (1) to determine the bio-aerosol types and levels for the first time for Bolu in PM10 composition; (2) to roughly determine the first-time visibility range for Bolu atmosphere by using the concentrationsof the parameters measured in the PM10 and PM2.5 composition and the relative humidity (RH) and finally, (3) to find the sources affecting the air quality in Bolu city center. To achieve these objectives, daily PM samples were collected on quartz filters using a high-volume sampler between 30 June-10 August (2017) and 22 February-25 March (2018) at a station located in the garden of the General Directorate of Meteorology in Bolu city center (40.7330°N, 31.6017°E). While the chemical compositions of collected PM samples were analyzed in terms of major ions, EC and OC, bio-aerosol analyzes were performed only for PM10 samples. Bioaerosols were determined by Real Time Polymerase Chain Reaction (RT-PCR). The data obtained from the PM composition were evaluated together with the meteorological factors, and the light extinction coefficient and visibility range values were calculated. The bioaerosol analysis showed that the most abundant bacterial phylum is Protebacteri and the fungal phylum Basidiomycota in PM10 samples. ARGs were identified as IntI-1, ctx-m-32, Sul1, qnrS, MecA. It was determined that the main pollutants affecting the light extinction coefficient were organic matter and sulfate ions. It has been found that the light extinction coefficient calculated with the improved IMPROVE method and the view distance value calculated accordingly give more accurate results. Due to the lack of bio-aerosol data in PM10 samples, no statistically strong correlation between the bio-aerosol levels and visibility range was detected in this study. PMF resolved four different sources affecting the air quality of Bolu. KEYWORDS: Bolu, PM10, PM2.5, Bio-aerosol, EC, OC, Ions, Visibility range, PMF