PM2.5 and PM10-2.5 chemical composition and source apportionment near a Hong Kong roadway

摘要: Abstract Twenty-four-hour PM 2.5 and 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 , 10-2.5 (defined as  − PM ), organic carbon (OC), elemental (EC), water-soluble ions, up 25 elements determined. Investigation the chemical compositions potential sources revealed distinct differences between . annual average 55.5 ± 25.5 25.9 ± 15.7 μg/m 3 for respectively. EC, OM (OM = OC × 1.4), ammonium sulfate comprised over ∼82% accounting ∼29%, ∼27%, ∼25%, respectively, mass. Low OC/EC ratios (less than 1) suggested that fresh diesel-engine exhaust was major contributor. Seven resolved by positive matrix factorization (PMF) model, including vehicle emissions (∼29%), secondary inorganic aerosols (∼27%), waste incinerator/biomass burning (∼23%), residual oil combustion (∼10%), marine (∼6%), industrial (∼4%), resuspended road dust (∼1%). EC only ∼19% ratio 7.8 ± 14.2, suggesting other vehicular important contributors. determined PMF model included ∼20% traffic-generated resuspension (e.g., tire dust/brake linear/petrol evaporation), ∼17% locally dust, aerosols, ∼12% aerosols/field burning, ∼11% emissions.