Risk-Based Prioritization among Air Pollution Control Strategies in the Yangtze River Delta, China

Article excerpt

BACKGROUND: The Yangtze River Delta (YRD) in China is a densely populated region with recent dramatic increases in energy consumption and atmospheric emissions.

OBJECTIVES: We studied how different emission sectors influence population exposures and the corresponding health risks, to inform air pollution control strategy design.

METHODS: We applied the Community Multiscale Air Quality (CMAQ) Modeling System to model the marginal contribution to baseline concentrations from different sectors. We focused on nitrogen oxide ([NO.sub.x]) control while considering other pollutants that affect fine particulate matter [aerodynamic diameter [less than or equal to] 2.5 [micro]m ([PM.sub.2.5])] and ozone concentrations. We developed concentration-response (C-R) functions for [PM.sub.2.5] and ozone mortality for China to evaluate the anticipated health benefits.

RESULTS: In the YRD, health benefits per ton of emission reductions varied significantly across pollutants, with reductions of primary [PM.sub.2.5] from the industry sector and mobile sources showing the greatest benefits of 0.1 fewer deaths per year per ton of emission reduction. Combining estimates of health benefits per ton with potential emission reductions, the greatest mortality reduction of 12,000 fewer deaths per year [95% confidence interval (CI), 1,200-24,000] was associated with controlling primary [PM.sub.2.5] emissions from the industry sector and reducing sulfur dioxide ([SO.sub.2]) from the power sector, respectively. Benefits were lower for reducing [NO.sub.x] emissions given lower consequent reductions in the formation of secondary [PM.sub.2.5] (compared with [SO.sub.2]) and increases in ozone concentrations that would result in the YRD.

CONCLUSIONS: Although uncertainties related to C-R functions are significant, the estimated health benefits of emission reductions in the YRD are substantial, especially for sectors and pollutants with both higher health benefits per unit emission reductions and large potential for emission reductions.

KEY WORDS: air pollution, China, CMAQ, health risk, ozone, [PM.sub.2.5], Yangtze River Delta. Environ Health Perspect 118:1204-1210 (2010). doi:10.1289/ehp.l00l991 [Online 17 May 2010]

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The Yangtze River Delta (YRD), which generally refers to southern Jiangsu Province, eastern and northern Zhejiang Province, and the municipality of Shanghai, is the fastest growing economic development region in China and one of the most densely populated regions in the world. Shanghai is one of the world's largest cities, with > 18 million long-term residents and a population density of > 40,000 people/[km.sup.2] in some districts. Accompanying this economic development has been a dramatic increase in energy consumption and air pollution emissions. For example, although the Shanghai metropolitan area and the provinces of Jiangsu and Zhejiang constitute only 2% of the area of China, their emissions of sulfur dioxide ([SO.sub.2]), nitrogen oxides ([NO.sub.x]), and fine particulate matter [aerodynamic diameter [less than or equal to] 2.5 [micro]m ([PM.sub.2.5])] accounted for 12%, 15%, and 12%, respectively, of total emissions in China in 2006, which increased by 36%, 55%, and 14%, respectively, from 2001 to 2006 (Zhang et al. 2009). [NO.sub.x] emissions are of particular concern because they have increased the fastest and are forecasted to increase even more (Chen et al. 2006).

Several studies (Kan et al. 2004; Li et al. 2004; Streets et al. 1999) have evaluated the health benefits of air pollution control in Shanghai, primarily [SO.sub.2] and [PM.sub.10], and occasionally sulfate particles. Similar studies have been conducted in other parts of China, such as a recent estimate of annual deaths attributable to air pollution in the Pearl River Delta (Loh et al. 2008). In another study in the Pearl River Delta area, Wang et al. (2005) investigated how the emissions from different sectors influenced the concentrations of gaseous pollutants including ozone. …