Abstract. Heavy regional particulate matter (PM) pollution in China has resulted in an important and urgent need for joint control actions among cities. It is advisable to improve the understanding of the regional background concentration of PM for the development of efficient and effective joint control policies. With the increase of height the influence of source emission on local air quality decreases with altitude, but the characteristics of regional pollution gradually become obvious. A method to estimate regional background PM concentration is proposed in this paper, based on the vertical characteristics of periodic variation in the atmospheric boundary layer structure and particle mass concentration, as well as the vertical distribution of particle size, chemical composition and pollution source apportionment. According to the method, the averaged regional background PM2.5 concentration in July, August and September 2009, being extracted from the original time series in Tianjin, was 40 ± 20, 64 ± 17 and 53 ± 11 μg m−3, respectively.
Abstract. Heavy regional particulate matter (PM) pollution in China has resulted in an important and urgent need for joint control actions among cities. It's advisable to improve the understanding of regional background concentration of PM for the development of efficient and effective joint control policies. With the increase of vertical height the influence of source emission on local air quality is weakening, but the characteristics of regional pollution gradually become obvious. A method to estimate regional background PM concentration is proposed in this paper, based on the vertical variation periodic characteristics of the atmospheric boundary layer structure and particle mass concentration, as well as the vertical distribution of particle size, chemical composition and pollution source apportionment. According to the method, the averaged regional background PM2.5 concentration, being extracted from the original time series in Tianjin, was 40.0 ± 20.2, 63.6 ± 16.9 and 53.2 ± 11.1 μg m−3, respectively, in July, August and September.
The rise of government micro-blogs opens a new era for the interaction between the government and the public. As critical stakeholders, the public's opinions on the operation of government micro-blogs are important for their future improvement. In order to explore the public's expectations on government micro-blogs, contents of public micro-blogs on government micro-blogs were collected and analyzed by adopting a grounded theory approach. A conceptual model of the public's expectation on government micro-blogs was generated and its policy implications were discussed. According to the model, a government micro-blog should clearly define its target, strengthen its functions, normalize its business process, and improve its maintenance and management in order to increase its service quality. Furthermore, improving the quality of information openness, strengthening interactions with the public, and advancing the capability of solving practical problems were found to be the three specific developmental orientations of government micro-blogs in the future.
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