| 1 | PM_(2.5) and PM_(10-2.5) chemical composition and source apportionment near a Hong Kong roadway显示文摘Twenty-four-hour PM_(2.5) and PM_(10) samples were collected simultaneously at a highly trafficked roadside site in Hong Kong every sixth day from October 2004 to September 2005.The mass concentrations of PM_(2.5),PM_(10-2.5)(defined as PM_(10)- PM_(2.5)),organic carbon(OC),elemental carbon(EC),water-soluble ions,and up to 25 elements were determined.Investigation of the chemical compositions and potential sources revealed distinct differences between PM_(2.5) and PM_(10-2.5).The annual average mass concentrations were 55.5±25.5 and 25.9±15.7 ug/m^3 for PM_(2.5) and PM_(10-2.5),respectively.EC,OM(OM =OC×1.4),and ammonium sulfate comprised over ~82% of PM_(2.5),accounting for^29%,~27%,and ~25%,respectively,of the PM_(2.5) mass.Low OC/EC ratios(less than 1) for PM_(2.5) suggested that fresh diesel-engine exhaust was a major contributor.Seven sources were resolved for PM_(2.5) by positive matrix factorization(PMF) model,including vehicle emissions(~29%),secondary inorganic aerosols(~27%),waste incinerator/biomass burning(~23%),residual oil combustion(~10%),marine aerosols(~6%),industrial exhaust(~4%),and resuspended road dust(~1%).EC and OM comprised only ~19%of PM_(10-2.5).The average OC/EC ratio of PM_(10-2.5) was 7.8±14.2,suggesting that sources other than vehicular exhaust were important contributors.The sources for PM_(10-2.5) determined by the PMF model included ~20%traffic-generated resuspension(e.g.,tire dust/brake linear/petrol evaporation),~17% locally resuspended road dust,~17% marine aerosols,~12% secondary aerosols/field burning,and ~11%vehicle emissions. | Yan Cheng Shuncheng Lee Zhaolin Gu Kinfai Ho Yunwei Zhang Yu Huang Judith C.Chow John G.Watson Junji Cao Renjian Zhang | 2015 | Particuology2015，13，1： | 14 |
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