PM1.0 and PM2.5 Characteristics in the Roadside Environment of Hong Kong

Daily mass concentrations of PM 1.0 (particles less than 1.0 μm in diameter), PM 2.5 (particles less than 2.5 μm in diameter), organic carbon (OC), and elemental carbon (EC) were measured from January through May 2004 at a heavily trafficked sampling site in Hong Kong (PU). The average concentrations for PM 1.0 and PM 2.5 were 35.9 ± 12.4 μ g cm − 3 and 52.3 ± 18.3 μ g cm − 3 . Carbonaceous aerosols were the dominant species in fine particles, accounting for ∼ 45.7% of PM 1.0 and ∼ 44.4% of PM 2.5 . During the study period, seven fine-particle episodes occurred, due to the influence of long-range transport of air masses from mainland China. PM 1.0 and PM 2.5 responded in similar ways; i.e., with elevated mass and OC concentrations in those episode days. During the sampling period, PM 1.0 OC and EC generally behaved similarly to the carbonaceous aerosols in PM 2.5 , regardless of seasonal variations and influence by regional pollutions. The low and relatively constant OC/EC ratios in PM 1.0 and PM 2.5 indicated that vehicular emissions were major sources of carbonaceous aerosols. PM 1.0 and PM 2.5 had the same dominant sources of vehicular emissions in winter, while in spring PM 2.5 was more influenced by PM 1 − 2.5 (particles 1–2.5 μ m in diameter) that did not form from vehicle exhausts. Therefore, PM 1.0 was a better indicator for vehicular emissions at the Roadside Station.

[1]  J. C. Cabada,et al.  Positive and Negative Artifacts in Particulate Organic Carbon Measurements with Denuded and Undenuded Sampler Configurations Special Issue of Aerosol Science and Technology on Findings from the Fine Particulate Matter Supersites Program , 2004 .

[2]  R. Charlson,et al.  Elemental carbon in the atmosphere: cycle and lifetime , 1983 .

[3]  J. Chow,et al.  PM2.5 and PM10 Concentrations from the Qalabotjha Low-Smoke Fuels Macro-Scale Experiment in South Africa , 2001, Environmental monitoring and assessment.

[4]  Allen L. Robinson,et al.  Positive and Negative Artifacts in Particulate Organic Carbon Measurements with Denuded and Undenuded Sampler Configurations Special Issue of Aerosol Science and Technology on Findings from the Fine Particulate Matter Supersites Program , 2004 .

[5]  Chak K. Chan,et al.  Characteristics of chemical compositions of atmospheric aerosols in Hong Kong: spatial and seasonal distributions , 1997 .

[6]  Barbara J. Turpin,et al.  Investigation of organic aerosol sampling artifacts in the los angeles basin , 1994 .

[7]  J Schwartz,et al.  Confounding and Effect Modification in the Short-Term Effects of Ambient Particles on Total Mortality: Results from 29 European Cities within the APHEA2 Project , 2001, Epidemiology.

[8]  Roy M. Harrison,et al.  Primary particle formation from vehicle emissions during exhaust dilution in the roadside atmosphere , 2003 .

[9]  Bong Mann Kim,et al.  Positive Organic Carbon Artifacts on Filter Medium During PM2.5 Sampling in the South Coast Air Basin , 2001 .

[10]  J. Pekkanen,et al.  Concentrations and Estimated Soot Content of PM1, PM2.5, and PM10 in a Subarctic Urban Atmosphere† , 2000 .

[11]  Judith C. Chow,et al.  The dri thermal/optical reflectance carbon analysis system: description, evaluation and applications in U.S. Air quality studies , 1993 .

[12]  R. Draxler.  NOAA Technical Memorandum ERL ARL-224 DESCRIPTION OF THE HYSPLIT_4 MODELING SYSTEM , 1999 .

[13]  J. C. Cabada,et al.  Mass size distributions and size resolved chemical composition of fine particulate matter at the Pittsburgh supersite , 2004 .

[14]  J. Chow,et al.  Characterization of chemical species in PM2.5 and PM10 aerosols in Hong kong , 2003 .

[15]  Virgil A. Marple,et al.  PM10/PM2.5/PM1 Data from a Trichotomous Sampler , 1996 .

[16]  Judith C. Chow,et al.  Comparison and evaluation of in situ and filter carbon measurements at the Fresno Supersite , 2002 .

[17]  A. Lau,et al.  Acidity and concentrations of ionic species of PM2.5 in Hong Kong , 2003 .

[18]  Yifang Zhu,et al.  Study of ultrafine particles near a major highway with heavy-duty diesel traffic , 2002 .

[19]  Hans Moosmüller,et al.  Equivalence of elemental carbon by thermal/optical reflectance and transmittance with different temperature protocols. , 2004, Environmental science & technology.

[20]  Chihshan Li,et al.  PM 1 /PM 2.5 /PM 10 Characteristics in the Urban Atmosphere of Taipei , 2002 .

[21]  Judith C Chow,et al.  PM2.5 chemical composition in Hong Kong: urban and regional variations. , 2005, The Science of the total environment.

[22]  Alexis K.H. Lau,et al.  Seasonal characteristics and regional transport of PM2.5 in Hong Kong , 2005 .

[23]  J. Schwartz,et al.  Is Daily Mortality Associated Specifically with Fine Particles? , 1996, Journal of the Air & Waste Management Association.

[24]  Roy M. Harrison,et al.  Sources and concentration of nanoparticles (<10 nm diameter) in the urban atmosphere , 2001 .

[25]  Byung-Wook Kang,et al.  Chemical characteristics of principal PM2.5 species in Chongju, South Korea , 2001 .

[26]  J. Fung,et al.  Abundance and seasonal characteristics of elemental and organic carbon in Hong Kong PM10 , 2004 .

[27]  D. Dockery,et al.  An association between air pollution and mortality in six U.S. cities. , 1993, The New England journal of medicine.

[28]  Timo Mäkelä,et al.  Intercomparison of methods to measure the mass concentration of the atmospheric aerosol during INTERCOMP2000: influence of instrumentation and size cuts , 2004 .

[29]  M. Keywood,et al.  Relationships between size segregated mass concentration data and ultrafine particle number concentrations in urban areas , 1999 .

[30]  Judith C. Chow,et al.  Characteristics of carbonaceous aerosol in Pearl River Delta Region, China during 2001 winter period , 2003 .