Search

Chemically speciated PM2.5 and particle-bound polycyclic aromatic hydrocarbon (PAH) measurements were made at three sites near urban Tong Liang, Chongqing, a Chinese inland city where coal combustion is used for electricity generation and residential purposes outside of the central city. Ambient sampling was based on 72-hr averages between 3/2/2002 and 2/26/2003. Elevated PM2.5 and PAR concentrations were observed at all three sites, with the highest concentrations found in winter and the lowest in summer. This reflects a coupling effect of source variability and meteorological conditions. The PM2.5 mass estimated from sulfate, nitrate, ammonium, organics, elemental carbon, crustal material, and salt corresponded with the annual average gravimetric mass within ± 10%. Carbonaceous aerosol was the dominant species, while positive correlations between organic carbon and trace elements (e.g., As, Se, Br, Pb, and Zn) were consistent with coal-burning and motor vehicle contributions. Ambient particle-bound PAHs of molecular weight 168-266 were enriched by 1.5 to 3.5 times during the coal-fired power plant operational period. However, further investigation is needed to determine the relative contribution from residential and utility coal combustion and vehicular activities. [ABSTRACT FROM AUTHOR]

On-road vehicular emissions were measured in a Hong Kong roadway tunnel and compared to those from a mobile emission model (EMFAC-HK) for the 2003 and 2015 fleets to assess emission changes and effectiveness of emission controls. EMFAC-HK results compared well with tunnel measurement for the 2015 fleet with differences ≤50% for most pollutants. Both measurement and modeled estimates show that non-methane hydrocarbon (NMHC) and PM 2.5 decreased by over 40% from 2003 to 2015. Tunnel measurements also show that nitrogen dioxide (NO 2) and liquefied petroleum gas (LPG) -related NMHC emissions increased due to expanded installation of diesel oxidation catalysts and LPG fueling. Motorcycles and LPG-fueled public light buses (3.7% of the fleet) contributed disproportionally high fractions of carbon monoxide (CO; 27%) and NMHC (49%) and deserve additional emission controls. Fuel economy improvements did not result in expected carbon dioxide (CO 2) emission reductions, indicating that more aggressive CO 2 reductions, particularly from heavy-duty vehicles, are needed. [Display omitted] • Emission model estimates for the 2015 Hong Kong fleet differed by <50% from tunnel measurements for most pollutants. • Vehicle NMHC and PM 2.5 emissions decreased by over 40% from 2003 to 2015. • CO 2 emissions did not decrease as anticipated by improved vehicle fuel economy. • Fleet-average NO 2 /NO x emission ratios increased from 6.7% in 2003 to 14.4% in 2015. • Motorcycles and LPG light buses are disproportionally high CO and NMHC emitters. [ABSTRACT FROM AUTHOR]