利用超级站PM2.5分子与元素示踪物小时数据解析香港城市尺度空气污染源.pdf

1、Informing city-scale air pollution episodes using hourly time-scale measurements of PM2.5molecular and elemental tracers at an air quality supersite in Hong Kong香港科技大学化学系；环境与可持续发展学部郁建珍教授(Prof.YU Jianzhen）Hong Kong University of Science&Technology利用超级站利用超级站PMPM2.52.5分子与元素示踪物小时数据解析香港城市尺度空气污染源分子与元素示踪物小

2、时数据解析香港城市尺度空气污染源2025/08/282025 Yangtze River Delta Clean Air Forum Introduction:Haze pollution in Hong Kong2 Annual PM2.5 levels decreased significantly in Hong Kong(48%reductions),in compliance with the national annual air quality objectives of 35 g m-3 in recent years Short-term(several hours to f

3、ew days)PM2.5 pollution sporadically occurred in winter and has become a major focus of public attentionHK annual AQOPM2.5:25 g/m3Introduction:Haze pollution in China3Organic aerosols(OA)becomes increasing more important,as the inorganic ion constituents have decreased notable in the past decadeUrba

4、n stationBlack carbonSulfateIntroduction:Molecular and elemental source tracers Come from either direct emissions from specific source or atmospheric oxidation of specific VOC precursors Provide clues to identify various specific sources and/or associated precursors4V,NiNaClCa,Fe,AlK,Cu,BaSOA tracer

5、s4-nitrocatecholHopanesPAHsFatty acidsLevoglucosanIntroduction:Importance of molecular tracers5 Without organic molecular tracers,organics-dominant sources(e.g.,biomass burning,biogenic sources,cooking emissions)could not be resolved Without secondary organic aerosol(SOA)tracers,secondary source con

6、tributions to PM2.5,especially to OC are notably underestimated.Molecular tracers are crucial to apportion various primary and secondary organics-dominant sources through providing unambiguous source information.(Chow et al.,2022;Wang et al.,2017)Introduction:Limitations with offline measurements6 N