Chemically-speciated on-road PM2.5 motor vehicle emission factors in Hong Kong

Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada, USA
Science of The Total Environment (Impact Factor: 4.1). 03/2010; 408(7):1621-1627. DOI: 10.1016/j.scitotenv.2009.11.061
Source: PubMed


PM2.5 (particle with an aerodynamic diameter less than 2.5 µm) was measured in different microenvironments of Hong Kong (including one urban tunnel, one Hong Kong/Mainland boundary roadside site, two urban roadside sites, and one urban ambient site) in 2003. The concentrations of organic carbon (OC), elemental carbon (EC), water-soluble ions, and up to 40 elements (Na to U) were determined. The average PM2.5 mass concentrations were 229 ± 90, 129 ± 95, 69 ± 12, 49 ± 18 µg m− 3 in the urban tunnel, cross boundary roadside, urban roadside, and urban ambient environments, respectively. Carbonaceous particles (sum of organic material [OM] and EC) were the dominant constituents, on average, accounting for ∼ 82% of PM2.5 emissions in the tunnel, ∼ 70% at the three roadside sites, and ∼ 48% at the ambient site, respectively. The OC/EC ratios were 0.6 ± 0.2 and 0.8 ± 0.1 at the tunnel and roadside sites, respectively, suggesting carbonaceous aerosols were mainly from vehicle exhausts. Higher OC/EC ratio (1.9 ± 0.7) occurred at the ambient site, indicating contributions from secondary organic aerosols. The PM2.5 emission factor for on-road diesel-fueled vehicles in the urban area of Hong Kong was 257 ± 31 mg veh− 1 km− 1, with a composition of ∼ 51% EC, ∼ 26% OC, and ∼ 9% SO4=. The other inorganic ions and elements made up ∼ 11% of the total PM2.5 emissions. OC composed the largest fraction (∼ 51%) in gasoline and liquid petroleum gas (LPG) emissions, followed by EC (∼ 19%). Diesel engines showed higher emission rates than did gasoline and LPG engines for most pollutants, except for V, Br, Sb, and Ba.

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Available from: John G Watson, Oct 04, 2015
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    • "The characteristics of these profiles are identical to those from a Hong Kong tunnel study (Cheng, Lee, et al., 2010) and previous studies on vehicle emissions (Gertler et al., 2002; Norbeck et al., 1998). The second largest contributor, which accounted for ∼27% of PM 2.5 , was characterized by large sulfate, ammonium, nitrate, and soluble sodium contributions, suggesting it was associated with secondary inorganic aerosols. "
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    ABSTRACT: Twenty-four-hour PM2.5 and PM10 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 PM2.5, PM10-2.5 (defined as PM10 − PM2.5), 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 PM2.5 and PM10-2.5. The annual average mass concentrations were 55.5 ± 25.5 and 25.9 ± 15.7 μg/m3 for PM2.5 and PM10-2.5, respectively. EC, OM (OM = OC × 1.4), and ammonium sulfate comprised over ∼82% of PM2.5, accounting for ∼29%, ∼27%, and ∼25%, respectively, of the PM2.5 mass. Low OC/EC ratios (less than 1) for PM2.5 suggested that fresh diesel-engine exhaust was a major contributor. Seven sources were resolved for PM2.5 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 PM10-2.5. The average OC/EC ratio of PM10-2.5 was 7.8 ± 14.2, suggesting that sources other than vehicular exhaust were important contributors. The sources for PM10-2.5 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.
    Particuology 12/2015; 18:96-104. DOI:10.1016/j.partic.2013.10.003 · 2.11 Impact Factor
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    • "From Fig. 1, schools with high concentrations of Pb (e.g., S15, S17 and S19) were also found to have high concentrations of hopanes that were attributed primarily to vehicle emissions in our previous work (Crilley et al., 2014b). However the correlations were poor between Pb, Br and these hopanes, which may be due to differing traffic composition between the schools (Table 1) as gasoline and diesel vehicles have been observed to have varying emission rates of Pb, Br and hopanes (Rogge et al., 1993; Lin et al., 2005; Phuleria et al., 2006; Cheng et al., 2010). Furthermore, elements which have previously been assigned to vehicle wear emissions (e.g., Fe, Cu and Zn) (Thorpe and Harrison, 2008; Gietl et al., 2010; Harrison et al., 2012b) did not have high loadings in this component, suggesting that there was limited input from non-exhaust emissions in this factor, possibly as these particles are present more in the coarse particle fraction (Iijima et al., 2007; Bukowiecki et al., 2009). "
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    ABSTRACT: Currently, there is a limited understanding of the sources of ambient fine particles that contribute to the exposure of children at urban schools. Since the size and chemical composition of airborne particle are key parameters for determining the source as well as toxicity, PM1 particles (mass concentration of particles with an aerodynamic diameter less than 1 µm) were collected at 24 urban schools in Brisbane, Australia and their elemental composition determined. Based on the elemental composition four main sources were identified; secondary sulphates, biomass burning, vehicle and industrial emissions. The largest contributing source was industrial emissions and this was considered as the main source of trace elements in the PM1 that children were exposed to at school. PM1 concentrations at the schools were compared to the elemental composition of the PM2.5 particles (mass concentration of particles with an aerodynamic diameter less than 2.5 µm) from a previous study conducted at a suburban and roadside site in Brisbane. This comparison revealed that the more toxic heavy metals (V, Cr, Ni, Cu, Zn and Pb), mostly from vehicle and industrial emissions, were predominantly in the PM1 fraction. Thus, the results from this study points to PM1 as a potentially better particle size fraction for investigating the health effects of airborne particles.
    Aerosol and Air Quality Research 12/2014; 14(7):1906-1916. DOI:10.4209/aaqr.2014.04.0077 · 2.09 Impact Factor
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    • "The research on airborne particulate matter (PM) involves the study of their size and composition (Kulshrestha et al. 2009; Zhao et al. 2009; Cheng et al. 2010; Aldabe et al. 2011). Ambient PM with an aerodynamic diameter\10 lm (PM 10 ), especially the fraction B2.5 lm (PM 2.5 ), has been associated with an increase in morbidity and mortality (Pope et al. 2002). "
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    ABSTRACT: The increase in platinum (Pt) in the airborne particulate matter with size ≤2.5 µm (PM2.5) in urban environments may be interpreted as result of the abrasion and deterioration of automobile catalyst. Nowadays, about four million vehicles in Mexico City use catalytic converters, which means that their impact should be considered. In order to evaluate the contribution of Pt to environmental pollution of the metropolitan area of Mexico City (MAMC), airborne PM2.5 was collected at five different sites in the urban area (NW, NE, C, SW, SE) in 2011 during April (dry-warm season), August (rainy season) and December (dry-cold season). Analytical determinations were carried out using a ICP-MS with a collision cell and kinetic energy discrimination. The analytical and instrument performance was evaluated with standard road dust reference material (BCR-723). Median Pt concentration in the analyzed particulate was is 38.4 pg m(-3) (minimal value 1 pg m(-3) maximal value 79 pg m(-3)). Obtained Pt concentrations are higher than those reported for other urban areas. Spatial variation shows that SW had Pt concentration significantly higher than NW and C only. Seasonal variation shows that Pt median was higher in rainy season than in both dry seasons. A comparison of these results with previously reported data of PM10 from 1991 and 2003 in the same studied area shows a worrying increase in the concentration of Pt in the air environment of MAMC.
    Environmental Geochemistry and Health 04/2014; 36(5). DOI:10.1007/s10653-014-9613-8 · 2.57 Impact Factor
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