Qiao Xue, Jaffe Daniel, Tang Ya, Bresnahan Meaghan, Song Jie
Department of Environment, College of Architecture and Environment, Sichuan University, Chengdu, 610065, China.
Environ Monit Assess. 2015 May;187(5):250. doi: 10.1007/s10661-015-4500-z. Epub 2015 Apr 15.
Air quality evaluation is important in order to inform the public about the risk level of air pollution to human health. To better assess air quality, China released its new national ambient air quality standards (NAAQS-2012) and the new method to classify air quality level (AQL) in 2012. In this study, we examined the performance of China's NAAQS-2012 and AQL classification method through applying them, the World Health Organization (WHO) guidelines, and the US AQL classification method to evaluate air quality in Chengdu, the largest city in southwestern China. The results show that annual mean concentrations of PM₁₀, PM₂.₅, SO₂, NO₂, and O₃ at the seven urban sites were in the ranges of 138-161, 87-98, 18-32, 54-70, and 42-57 μg/m(3), respectively, and the annual mean concentrations of CO were in the range of 1.09-1.28 mg/m(3). Chengdu is located in one of the four largest regions affected by haze in China, and PM₁₀ and PM₂.₅ were the top air pollutants, with annual concentrations over 2 times of their standards in NAAQS-2012 and over 7 times of the WHO guidelines. Annual mean concentrations of the pollutants were much lower at the background site (LYS) than at the urban sites, but the annual mean concentrations of PM₁₀ and PM₂.₅ at LYS were 3.5 and 5.7 times of the WHO guidelines, respectively. These suggest that severe air pollution in Chengdu was largely associated with local emissions but also related to regional air pollution. The compliance rates of PM₁₀ , PM₂.₅, SO₂, and O₃ met China's NAAQS-2012 standards four times more frequently than they met the WHO guidelines, as NAAQS-2012 uses the loosest interim target (IT) standards of WHO for these four pollutants. Air pollution in Chengdu was estimated and stated to be less severe using China's classification than using the US classification, as China uses weaker concentration breakpoints and benign descriptions of AQL. Furthermore, China's AQL classification method does not capture the cumulative effects of multiple pollutants, and the risk assessment is mainly based on the exposure-response relationship between air pollutant and human health quantified in the North America and West Europe; these can bring some uncertainties into evaluating the risk to human health in China. In summary, although China greatly improved its NAAQS and AQL classification method in 2012, further improvements are still needed.
空气质量评估对于向公众告知空气污染对人类健康的风险程度至关重要。为了更好地评估空气质量，中国于2012年发布了新的国家环境空气质量标准（NAAQS - 2012）以及空气质量等级（AQL）分类新方法。在本研究中，我们通过将中国的NAAQS - 2012和AQL分类方法、世界卫生组织（WHO）指南以及美国AQL分类方法应用于评估中国西南部最大城市成都的空气质量，来检验它们的性能。结果表明，七个城市监测点的PM₁₀、PM₂.₅、SO₂、NO₂和O₃的年均浓度分别在138 - 161、87 - 98、18 - 32、54 - 70和42 - 57 μg/m³范围内，CO的年均浓度在1.09 - 1.28 mg/m³范围内。成都位于中国受雾霾影响最严重的四大区域之一，PM₁₀和PM₂.₅是首要空气污染物，其年浓度超过NAAQS - 2012标准的两倍多，超过WHO指南的七倍多。背景监测点（LYS）污染物的年均浓度远低于城市监测点，但LYS处PM₁₀和PM₂.₅的年均浓度分别是WHO指南的3.5倍和5.7倍。这些表明成都的严重空气污染在很大程度上与本地排放有关，但也与区域空气污染有关。PM₁₀、PM₂.₅、SO₂和O₃符合中国NAAQS - 2012标准的频率比符合WHO指南的频率高出四倍，因为NAAQS - 2012对这四种污染物采用了WHO最宽松的临时目标（IT）标准。据估计，与美国的分类相比，使用中国的分类法表明成都的空气污染不太严重，因为中国使用的浓度断点较弱且对AQL的描述较为宽松。此外，中国的AQL分类方法没有考虑多种污染物的累积影响，并且风险评估主要基于北美和西欧量化的空气污染物与人类健康之间的暴露 - 反应关系；这些可能给评估中国的人类健康风险带来一些不确定性。总之，尽管中国在2012年大幅改进了其NAAQS和AQL分类方法，但仍需进一步改进。
