Characteristics of fine particle matter at the top of Shanghai Tower

Abstract. To investigate the physical and chemical processes of fine particle matter (PM) at mid-upper planetary boundary layer (PBL), we conducted 1-year continuous measurements PM, composition non-refractory submicron aerosol (NR-PM1), some gas species (including sulfur dioxide, nitrogen oxides, ozone) an opening observatory (∼ 600 m) top Shanghai Tower (SHT), which is China's first world's second highest building located in typical financial central business district Shanghai, China. This report on characteristics particles based sophisticated online level urban PBL. The observed PM2.5 PM1 mass concentrations SHT were 25.5 ± 17.7 17.3 11.7 µg m−3, respectively. Organics, nitrate (NO3), sulfate (SO4) occupied three leading contributions to NR-PM1 SHT, accounting for 35.8 %, 28.6 20.8 lower concentration was by 16.4 % compared with that near surface during observation period. It attributed decreased nighttime (29.4 than surface) all seasons due complete isolations from both emissions precursors surface. However, daytime 12.4 %–35.1 higher those June October, resulted unexpected larger levels early middle afternoon We suppose significant production secondary aerosols existed PBL, because strong solar irradiance, adequate (e.g., NOx), temperature favorable photochemical gas-to-particle partitioning. further demonstrated increasing rate oxygenated organic NO3 08:00–12:00 spring (7.4 h−1 12.9 h−1), fall (9.3 9.1 summer (13.0 11.4 cannot be fully explained vertical mixing. noted extremely high winter, 37.2 NR-PM1, suggesting efficient pathway heterogeneous oxidation formation. Therefore, highlight priority NOx reduction improvement air quality. study reported greater height m PBL measurement, providing insight into their potential effects local quality, radiation forcing, cloud and/or fog formations. propose should cognized explored more comprehensively synergetic observations future.