[A-AS08] Atmospheric Chemistry

[AAS08-P12] Quantitative Evaluation of Wet Scavenging of Near Surface Black Carbon in Urban Atmospheres

*Kamiya Yoshikazu¹, Hitoshi Irie¹, Morino Yu³, Pradeep Khatri² (1.Chiba University Center for Environmental Remote Sensing, 2.Soka University, 3.National Institute for Environmental Studies)

Keywords:

Black Carbon,Wet Scavenging,Urbun Atmospheres,Near-Surface

This study focuses on black carbon (BC), an important short-lived climate pollutant, and aims to quantitative evaluate the wet scavenging of near-surface BC around Chiba, Japan, which is characterized by urban atmospheric conditions. Three years of continuous observations of BC mass concentrations from 2023 to 2025 were conducted using a high-precision black carbon monitor (BCM Model 3130) at the Chiba University Atmospheric Environment Monitoring Supersite, where carbon dioxide (CO₂) measurements using in-situ trace gas analyzers and nitrogen dioxide (NO₂) measurements using International Air Quality and SKY Research Remote Sensing Network Multi-Axis Differential Optical Absorption Spectroscopy (A-SKY/MAX-DOAS) were also available. On average, BC mass concentrations immediately after individual precipitation events were lower than those before the events. However, simultaneous CO₂ and NO₂ measurements indicated that BC mass concentrations varied substantially due to advection and diffusion (AD) from local emissions, even during precipitation events.These influences were quantitatively accounted for by utilizing simultaneous BC/CO₂/NO₂ measurements, and an attempt was made to estimate BC mass concentrations immediately after precipitation using wet scavenging parameterizations reported in the literature for remote atmospheres. We found that considering both wet scavenging and AD reproduced post-precipitation BC mass concentration more reasonably than considering either factor alone, indicating that wet scavenging parameterizations reported in the literature are also applicable to urban atmospheres.