2000~2016年中国PM2.5时空格局

本文在检验PM_2.5遥感数据可靠性的基础上，使用标准偏差分析、Hurst指数、Theil-Sen median趋势分析与Mann-Kendall检验和局部空间自相关等方法，在像元尺度上研究了2000~2016年中国PM_2.5浓度的分布格局和演变过程.结果表明：①在空间分布上，PM_2.5的浓度东部高，多年平均值为30.21μg/m³，西部低，多年平均值为4.37μg/m³，东西两侧差异巨大.西部地区和东北地区PM_2.5的浓度整体呈现增长的态势，但西部地区变化较为平缓.PM_2.5污染严重的区域分布在人口多且密集，经济较为发达的区域，如华北平原，东北平原，长江中下游平原，四川盆地等地区.②在时间序列上，以2007年为界，PM_2.5的年变化趋势可分为两个阶段，从2000~2007期间我国的PM_2.5浓度总体呈现上升趋势，年均增长0.95μg/m³，2007~2016年PM_2.5浓度呈波动下降趋势，年均下降0.15 μg/m³；③稳定性：PM_2.5浓度的稳定性在空间上差异显著，整体呈现出西部较稳定、东部不稳定的分布状态.东部极不稳定区域主要分布在四川盆地，华北平原，东北平原中部，长江中下游平原；④持续性：中国PM_2.5持续性特征以弱反持续为主，主要分布在中国东部地区，预测未来PM_2.5的变化规律与目前相反.其次弱持续性分布的区域较广，主要分布在山地、高原及高寒地区，说明这一区域未来PM_2.5变化趋势与过去的变化趋势相同，但又具有复杂性和反复性.⑤人口暴露分析：分析不同PM_2.5浓度级别上的人口百分比，发现2016年中国有52%的人口生活在PM_2.5浓度年平均值为35 μg/m³以上的环境中，还有14.38%的人暴露在PM_2.5年均浓度值为60 μg/m³以上的环境中.

Spatiotemporal pattern of PM2.5 from 2000 to 2016 in China

After testing the reliability of PM_2.5 remote sensing data, the distribution pattern and evolution process of PM_2.5 concentration from 2000 to 2016 in China were investigated at the pixel scale with the standard deviation analysis, Hurst index, Theil-Sen median trend analysis, Mann-Kendall test, and together with local spatial autocorrelation analysis. The results showed that: ①the concentration of PM_2.5 was higher in the east with the annual average of 30.21μg/m³, and much lower in the west with the annual average of 4.37μg/m³. PM_2.5 concentration in the western and northeastern regions showed an increasing trend. However, the change in the west was relatively moderate. The areas with severe PM_2.5 pollution tended to have a large and dense population and a developed economy, such as the North China Plain, the Northeast Plain, the middle and lower reaches of the Yangtze River, and the Sichuan Basin, etc. ②Taking the year of 2007 as the cutoff time, the annual changing trend of PM_2.5 concentration could be divided into two stages. China's PM_2.5 concentration generally showed an increasing trend from 2000 to 2007 with an average annual increase of 0.95μg/m³, compared with a fluctuating and downward trend from 2007 to 2016 with an average annual decrease of 0.15μg/m³. ③Dramatic spatial differences in the stability of PM_2.5 concentration were observed in the study period with more stability in the west and less in the east. Extremely unstable areas mainly consisted of the Sichuan Basin, the North China Plain, the central part of Northeast Plain, and the middle and lower reaches of the Yangtze River. ④ a high PM_2.5 concentration and strong anti-sustainability were mostly observed in the eastern region, whose future change would be predicted to be contrary to the current state. The areas with poor sustainability mainly consisted of mountainous, plateau-like and cold regions, indicating a similar trend of PM_2.5 concentration as in the past but also showing the complexity and repeatability. ⑤ In 2016, 52% of people in China were exposed to an environment with an annual average PM_2.5 concentration of 35μg/m³ or above, and14.38% of people were exposed to 60μg/m³ or above.