School of Engineering and Applied Sciences, Harvard University, 29 Oxford St, Cambridge, MA 02138, USA.
Sci Total Environ. 2011 Nov 15;409(24):5177-87. doi: 10.1016/j.scitotenv.2011.08.026. Epub 2011 Sep 22.
Policies to control emissions of criteria pollutants in China may have conflicting impacts on public health, soil acidification, and climate. Two scenarios for 2020, a base case without anticipated control measures and a more realistic case including such controls, are evaluated to quantify the effects of the policies on emissions and resulting environmental outcomes. Large benefits to public health can be expected from the controls, attributed mainly to reduced emissions of primary PM and gaseous PM precursors, and thus lower ambient concentrations of PM2.5. Approximately 4% of all-cause mortality in the country can be avoided (95% confidence interval: 1-7%), particularly in eastern and north-central China, regions with large population densities and high levels of PM2.5. Surface ozone levels, however, are estimated to increase in parts of those regions, despite NOX reductions. This implies VOC-limited conditions. Even with significant reduction of SO2 and NOX emissions, the controls will not significantly mitigate risks of soil acidification, judged by the exceedance levels of critical load (CL). This is due to the decrease in primary PM emissions, with the consequent reduction in deposition of alkaline base cations. Compared to 2005, even larger CL exceedances are found for both scenarios in 2020, implying that PM control may negate any recovery from soil acidification due to SO2 reductions. Noting large uncertainties, current polices to control emissions of criteria pollutants in China will not reduce climate warming, since controlling SO2 emissions also reduces reflective secondary aerosols. Black carbon emission is an important source of uncertainty concerning the effects of Chinese control policies on global temperature change. Given these conflicts, greater consideration should be paid to reconciling varied environmental objectives, and emission control strategies should target not only criteria pollutants but also species such as VOCs and CO2.
中国控制污染物排放政策可能会对公众健康、土壤酸化和气候产生冲突影响。为了量化政策对排放和由此产生的环境结果的影响，评估了 2020 年的两个情景，一个是没有预期控制措施的基础情景，另一个是包括这些控制措施的更现实情景。可以预期控制措施将对公众健康产生巨大益处，这主要归因于减少了一次 PM 和气态 PM 前体的排放，从而降低了 PM2.5 的环境浓度。全国范围内约有 4%的总死亡率（95%置信区间：1-7%）可以避免，特别是在人口密度大、PM2.5 水平高的中国东部和中北部地区。然而，尽管氮氧化物减少了，预计部分地区的地表臭氧水平仍会增加。这意味着存在 VOC 限制条件。即使 SO2 和 NOX 的排放量显著减少，控制措施也不会显著减轻土壤酸化的风险，这是根据临界负荷（CL）的超标水平来判断的。这是由于一次 PM 排放的减少，导致碱性基础阳离子的沉积减少。与 2005 年相比，即使在 2020 年，两个情景的 CL 超标都更大，这意味着 PM 控制可能会抵消由于 SO2 减少而导致的土壤酸化的任何恢复。需要注意的是，存在很大的不确定性，中国目前控制污染物排放的政策不会减少气候变暖，因为控制 SO2 排放也会减少反射性二次气溶胶。黑碳排放是中国控制政策对全球气候变化影响的一个重要不确定性来源。考虑到这些冲突，应该更加重视协调各种环境目标，排放控制策略不仅应该针对污染物，还应该针对 VOCs 和 CO2 等物种。
