title: An optimum city size? The scaling relationship for urban population and fine particulate (PM(2.5)) concentration.
abstract: We utilize the distribution of PM2.5 concentration and population in large cities at the global scale to illustrate the relationship between urbanization and urban air quality. We found: 1) The relationship varies greatly among continents and countries. Large cities in North America, Europe, and Latin America have better air quality than those in other continents, while those in China and India have the worst air quality. 2) The relationships between urban population size and PM2.5 concentration in large cities of different continents or countries were different. PM2.5 concentration in large cities in North America, Europe, and Latin America showed little fluctuation or a small increasing trend, but those in Africa and India represent a "U" type relationship and in China represent an inverse "U" type relationship. 3) The potential contribution of population to PM2.5 concentration was higher in the large cities in China and India, but lower in other large cities.
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: ljhan@rcees.ac.cn.
authors.forename: Lijian
authors.initials: L
authors.lastname: Han
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China. Electronic address: wzhou@rcees.ac.cn.
authors.forename: Weiqi
authors.initials: W
authors.lastname: Zhou
authors.affiliation: Cary Institute of Ecosystem Studies, Millbrook, NY 12545-0129, United States.
authors.forename: Steward T A
authors.initials: STA
authors.lastname: Pickett
authors.affiliation: State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Li
authors.affiliation: School of Urban Planning and Design, Peking University Shenzhen Graduate School, Shenzhen 518055, China.
authors.forename: Li
authors.initials: L
authors.lastname: Li
mesh_terms: D000397:Air Pollution / Q000032:analysis*; D002947:Cities; D004784:Environmental Monitoring; D006801:Humans; D008962:Models, Theoretical; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis* / Q000737:chemistry; D011156:Population Density; D014507:Urbanization
chemical_list: D052638:Particulate Matter
keywords: Developed country; Developing country; Urban air quality; Urbanization