近10年中国大气PM_(10)污染时空格局演变

Spatio-temporal pattern changes of ambient air PM_(10) pollution in China from 2002 to 2012

为分析近10年来中国PM10污染时空格局演变,运用统计学和GIS方法对2002-2012年PM10监测数据进行分析,结果表明:①地级及以上城市ρ(PM10)年均值由0.130 mg·m-3下降至0.076 mg·m-3,达标城市比例由37.6%上升至92.0%;环保重点城市ρ(PM10)日均值超标天数比例由24.7%下降至7.0%。②12月份PM10污染最重,其次为1月和11月;8月份污染最轻,其次为7月和9月。③PM10的重污染区域明显减小,由集中连片分布变为零星点状分布。但空间格局未发生明显变化,北方尤其是西北、华北地区及山东、江苏、湖北一直是PM10污染相对严重地区。④北方地区PM10污染重于南方地区,两者的差异主要发生在北方采暖期(1-4月及11-12月)。⑤PM10污染的改善主要体现在重污染城市的改善,1/10左右的重污染城市对降低全国PM10平均浓度的贡献约占1/3,而清洁城市PM10污染则有加重趋势。⑥环保重点城市污染天气以轻度污染为主,占全部污染天数的80.4%。受沙尘天气影响,3、4月份发生严重污染天气的比例较高。

Based on the annual average daily concentration of PM10 by city was collected from 2002 to 2012, the statistical and GIS methods were used to study the spatio-temporal changes of concentration of PM10 in ambient air of China. The results showed that during the study period, （1） annual daily average concentration of PM10 in cities at or above prefecture level decreased from 0.130 mg·m^-3 to 0.076 mg·m^-3, and the proportion of cities meeting the Grade II national air quality standard increased from 37.6% to 92%. （2） PM10 had a highest monthly average concentration in December, followed by January and November; and showed a lowest monthly average concentration in August, followed by July and September. （3） Seriously PM10 polluted areas decreased significantly, and the distribution type changed from centralized distribution to scattered punctuate distribution. But the spatial pattern of PM10 pollution did not change obviously. Northern China, especially northwest China, north China, Shandong, Jiangsu and Hubei were still the relatively serious PM10 polluted areas. （4） PM10 pollution was more serious in northern China than in southern China, and this difference was mainly observed in heating season （from November to next April）. （5） Mitigation of PM10 pollution was mainly reflected on the decrease of seriously polluted cities, which accounted for 1/10 of all the cities, and could reduce about 1/3 of the national average concentration of PM10. Different from heavily PM!0 polluted cities, the situation of PM10 pollution in relatively clean cities showed an aggravating trend. （6） The PM10 pollution in major environmental protection cities was slightly polluted, accounting for 80.4% of the total number of pollution days. The proportion of serious pollution day was higher in March and April due to the dust-sand weather. The results can provide reference for a better understanding of the situation and changing trend of atmospheric particulate matter pollution in China, and of significance to help the governments at all levels or policy makers to make targeted prevention and control on particulate matters pollution.