[Exposure Level of Population and Economy in Zhejiang Province Considering the Background of PM in East China].

Using the satellite-derived Fine Particulate Matter (PM) data of global high-precision products during 1998-2012, detailed characteristics of PM distribution over East China and its change are given, and the PM exposure levels for population and economy in Zhejiang is further analyzed in this context. The results show that the overall variability of the regional average value of PM concentration exhibits an increasing trend followed by a decrease during 1998-2012, which is consistent in both the East China and Zhejiang provinces; the turning point occurs around 2007-2009. In the initial years (1998-2000), annual average PM concentrations are below 50 μg·m in the southern part of East China and eastern part of Shandong, while it is 50-75 μg·m in other areas. During this period, 51.8% of the area in East China and 21.1% of the area in Zhejiang have PM concentrations larger than 35 μg·m (Air quality standard value in China). The rising trend in PM concentration is extremely obvious in 1998-2009; the mean linear trend over East China is 2.58 μg·(m·a), while it is 1.43 μg·(m·a) over Zhejiang province. PM concentration reaches its maximum during 2007-2009. The area where PM concentration is larger than 35 μg·m reaches 82.1% in East China and 65.9% in Zhejiang province. After that, the PM concentration begins to decrease in each region, and the average change trend in East China and Zhejiang are -1.75 μg·(m·a) and -1.58 μg·(m·a), respectively. The regional area in which PMconcentrations aregreater than 35 μg·m displays a slight decline during 2010-2012, which suggests that the energy conservation and emission reduction plan proposed by the Chinese government and associated measures may play a vital role in improving air quality of East China. In 2010, the proportion of the population and GDP for which the PM exposure level exceeded 35 μg·m were 74.0% and 70.8%, respectively, of which 38.1% of the population lives in an environment where annual average PM concentrations are more than 50 μg·m. In addition, 38.9% of the GDP is produced in an environment with annual average PM concentrations more than 50 μg·m.