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Abstract: Objective: Air-borne particulates from different sources could have different physicochemical properties and inflammatory potentials. This study aims to characterize the chemical compositions and the toxicity of ambient particulate matter (PM) associated with traffic emissions. Methods: The concentrations of trace elements, organic carbon (OC), elemental carbon (EC) and polycyclic aromatic hydrocarbons (PAHs) in PM2.5 and PM10 were measured in samples collected at sites in Beijing, China. Their toxic effects on the pulmonary system of rats were investigated. Biochemical parameters (LDH, T-AOC, TP) and inflammatory cytokine(IL-6, IL-1, TNF-a) levels were measured in the lungs of rats exposed to traffic-related PM. Oxidative damage was observed. PM samples were taken from a near road site and an off road site in summer time in 2006. Results: The concentrations of the USEPA priority pollutant PAHs in both PM10 and PM2.5 were higher (299.658 and 348.412) at the near road site than those (237.728 and 268.472) at the off road site. The similar trend was observed for the concentrations of trace elements in PM. Compared to coarse particles (PM10), fine particles (PM2.5) have a greater adsorption capacity to enrich toxic elements than inhalable particles. Decrease in antioxidant capacity and an increase in the amount of lipid peroxidation products in rat lung tissues was observed. Conclusion: The findings of the present study suggest that the differing inflammatory responses of PM collected from the two road sites might have been mediated by the differing physicochemical characteristics. [Copyright &y& Elsevier]

Fine particulate matter (PM 2.5 ) has attracted increasing attention due to its impacts on air quality and human health. As an important source of PM 2.5 , diesel vehicles are often the focus of research. In this study, we characterized the carbonaceous composition of PM 2.5 that is emitted from on-road China III diesel trucks (DTs). Organic carbon (OC), elemental carbon (EC), and PM 2.5 emission characteristics were determined for 17 China III DTs, including 6 light-duty diesel trucks (LDDTs), 5 medium-duty diesel trucks (MDDTs), and 6 heavy-duty diesel trucks (HDDTs), based on real-world measurements in Beijing, China, using a portable emissions measurement system (PEMS). The average distance-based PM 2.5 emission factors (EFs) (g km −1 ) generally increased and the average CO 2 -based PM 2.5 EFs (g (kg of CO 2 ) −1 ) generally decreased with increased vehicle size from LDDTs to MDDTs to HDDTs. The effects of driving conditions on the EFs for carbonaceous PM 2.5 were analyzed. The results show that distance-based and CO 2 -based EFs strongly depend on driving conditions. Generally, greater amounts of PM 2.5 and OC are emitted from non-highway driving cycles, and greater amounts of EC are emitted from highway driving cycles for vehicles of the same size. For LDDTs, MDDTs, and HDDTs, no significant differences were observed between vehicles with different EC/OC ratios; therefore, the EC/OC ratio is not useful for distinguishing between the emissions generated by differently sized vehicles. The EC/OC, OC/PM 2.5 , and EC/PM 2.5 mass ratios are strongly dependent on driving conditions for vehicles of the same size. The results of this study provide EFs for the carbonaceous composition of PM 2.5 that are more appropriate for China; these results will be helpful for improving policies that are designed to control the carbonaceous composition of PM 2.5 emitted from on-road DTs in China. [ABSTRACT FROM AUTHOR]

Abstract: Incorporated into the WRF–Chem model are the three HONO sources, i.e., the reaction of photo-excited NO2 with water (NO2 * chemistry), heterogeneous reactions on aerosol surfaces, and HONO emissions. Four case simulations were performed in Beijing, Tianjin, and Hebei Province (BTH region) in August of 2007. Results indicate that the NO2 * chemistry yields 30–50 ppb enhancements in daily maximum 1-h surface O3 concentrations in major cities and 3–10 ppb increases in monthly mean daily maximum 8-h surface O3 concentrations in most areas of the BTH region. Heterogeneous reactions on aerosol surfaces lead to 5–20 ppb decreases in monthly mean NOy concentrations in major cities over the BTH region. Heterogeneous reactions and HONO emissions are the largest, and the second largest contributor, accounting for ∼59% and 26% of simulated HONO concentrations, respectively. The three HONO sources produce enhancements in monthly mean daytime (10:00–17:00) concentrations of NOy (total reactive N-containing compounds), NO2, HNO3, HONO, and HOx being −1 to −5 ppb, −1 to −3 ppb, −0.3 to 0.5 ppb, 20–50 ppt, and 1–3 ppt, respectively. Comparison with observations shows that inclusion of the three HONO sources into the WRF–Chem model can considerably improve HONO and O3 simulations in the BTH region. For HONO the mean, the normal mean bias, the root mean square error, and the correlation coefficient is greatly improved from 0.04 to 0.56 ppb, from −97% to −39%, from 1.10 ppb to 0.51 ppb, and from −0.56 to 0.86, respectively, by comparison with the gas chemical mechanism only considered in the WRF–Chem model. This suggests that the three important HONO sources be included in air quality models, particularly in the areas with high emissions of NOx and particulate matter. [Copyright &y& Elsevier]

Provinces that provide emission-intensive products now are facing huge financial pressure to control regional air pollutant emissions. Assessing the actual regional air emission abatement costs of each province from the consumer perspective can help to clarify regional pollution abatement responsibilities and formulate sound monetary compensation policies between consumers and producers in China. In this study, we employ a multiregional input-output model to estimate the total air pollution abatement costs and economic benefits caused by interregional trade for each region in 2012. The results indicate that regions with higher GDP per capita, such as the Beijing-Tianjin, East Coast, and South Coast regions, outsourced total pollution abatement costs (TPAC) for air emissions to undeveloped central and western regions via interregional trade within China. Based on a comparison of the cost-benefit index among regions, wealthy regions left nearly 80% of their consumption-based value added locally but outsourced more than 50% of their consumption-based TPAC to other regions, especially to northwestern and central regions with lower GDP per capita. Such a mismatch necessitates in-depth cross-boundary collaboration for control of air pollutant emissions in regions suffering terrible haze problems, such as the North China Plain. • Regional air emission abatement costs embodied in interregional trade are assessed. • Central, Northwest, and North regions have higher production-based TPAC nationwide. • Developing regions suffered more air emission control costs from developed regions. • Shanxi suffered the highest inequity when trading with Beijing nationwide. [ABSTRACT FROM AUTHOR]