State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University , Nanjing, Jiangsu China.
Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology (CICAEET), Nanjing University of Information Science & Technology , Nanjing, Jiangsu China.
Environ Sci Technol. 2017 Nov 21;51(22):13161-13169. doi: 10.1021/acs.est.7b03468. Epub 2017 Nov 3.
China established ground PM monitoring network in late 2012 and hence the long-term and large-scale PM data were lacking before 2013. In this work, we developed a national-scale spatiotemporal linear mixed effects model to estimate the long-term PM concentrations in China from 1957 to 1964 and from 1973 to 2014 using ground visibility monitoring data as the primary predictor. The overall model-fitting and cross-validation R is 0.72 and 0.71, suggesting that the model is not overfitted. Validation beyond the model year (2014) indicated that the model could accurately estimate historical PM concentrations at the monthly (R = 0.71) level. The historical PM estimates suggest that air pollution is not a new environmental issue that occurs in the recent decades but a problem existing in a longer time before 1980. The PM concentrations have reached 60-80 μg/m in the north part of North China Plain during 1950s-1960s and increased to generally higher than 90 μg/m during 1970s. The results also show that the entire China experienced an overall increasing trend (0.19 μg/m/yr, P < 0.001) in PM concentrations from 1957 to 2014 with fluctuations among different periods. This paper demonstrated visibility data allow us to understand the spatiotemporal characteristics of PM pollution in China in a long-term.
中国于 2012 年末建立了地面 PM 监测网络，因此在 2013 年之前缺乏长期和大规模的 PM 数据。在这项工作中，我们开发了一个全国范围的时空线性混合效应模型，使用地面能见度监测数据作为主要预测因子，来估计 1957 年至 1964 年和 1973 年至 2014 年期间中国的长期 PM 浓度。总体模型拟合和交叉验证的 R 值分别为 0.72 和 0.71，表明模型没有过度拟合。超出模型年份（2014 年）的验证表明，该模型可以准确地估计每月的历史 PM 浓度（R=0.71）。历史 PM 估计表明，空气污染不是近几十年才出现的新环境问题，而是在 1980 年之前就存在的一个长期问题。在 20 世纪 50 年代至 60 年代，华北平原北部的 PM 浓度达到了 60-80μg/m，到 20 世纪 70 年代，PM 浓度普遍上升到 90μg/m 以上。结果还表明，从 1957 年到 2014 年，整个中国的 PM 浓度总体呈上升趋势（0.19μg/m/yr，P<0.001），不同时期存在波动。本文证明，能见度数据使我们能够长期了解中国 PM 污染的时空特征。
