Volatility parameterization of ambient organic aerosols at a rural site of the North China Plain

Abstract. The volatility of organic aerosols plays a key role in determining their gas–particle partitioning, which subsequently alters the physicochemical properties and atmospheric fates aerosol particles. Nevertheless, an accurate estimation (OAs) remains challenging because most standards for particulate compounds are not available, even those with standards, vapor pressures too low to be measured by traditional methods. Here, we deployed iodide-adduct long time-of-flight chemical ionization mass spectrometer (LToF-CIMS) coupled Filter Inlet Gases AEROsols (FIGAERO) probe relationship between molecular formulae aerosols' components volatilities. Tmax (i.e., temperature corresponding first signal peak thermogram) calibrants was abstracted validated from desorption thermograms mixed inorganic that were atomized then collected on PTFE filter, leading linear correlation volatility. In addition, 30 ambient filter samples winter 2019 at Wangdu station Beijing–Tianjin–Hebei region analyzed FIGAERO-LToF-CIMS, identification 1448 dominated CHO (containing carbon, hydrogen, oxygen atoms) CHON oxygen, nitrogen species. Among them, 181 including 91 90 selected since can characterized clear values more than 20 out divided into two groups according O / C ratios different thermal behavior. mean these is 0.56±0.35 (average ± 1 standard deviation) 0.18±0.08, respectively. Then parameterizations elemental composition group obtained. Compared previous parameterizations, our functions provide better low-volatility (LVOCs) aerosols. Furthermore, results suggest should specialized ratios.