Nonnegligible biogenic organic aerosol and the correlations with light absorption at three high altitude locations in the Qinghai–Tibetan Plateau

Abstract

To investigate the contribution of primary biological aerosol particles (PBAPs) to aerosol and the correlations with brown carbon (BrC) light absorption over the Tibetan Plateau (TP), the total suspended particle (TSP) samples were collected at three high altitude sites. The spatial variations of PBAPs tracers and absorption Ångström exponent (AAE) were obtained over the TP for the first time. Elevated PBAPs tracers concentrations were observed in the northeastern and southwestern sites compared to the central TP. The high concentrations of FSPD OC (the fungal-spore-derived OC and plant-debris OC) and PBAPs were obtained in the northeastern (with 74 ng m−3 and 2333 ng m−3) and southwestern sites (with 80 ng m−3 and 2682 ng m−3), respectively. The results indicated that PBAPs may be important fraction of BrC chromophores in the southwestern TP. The highest AAEs of BrC, primary BrC (BrCpri), and secondary BrC (BrCsec) were observed in the northeastern site with the values of 5.1, 3.7, and 5.7, respectively. The potential PBAPs and FSPD OC source distributions were obtained. The results are important for evaluating the effects of PBAPs in the TP.