title: [Evaluation of excess mortality caused by PM2.5 in four typical Chinese big cities].
abstract: OBJECTIVE
  To evaluate the adverse effects of particulate matter ≤ 2.5 µm in aerodynamic diameter (PM2.5) on public health in four typical cities: Beijing, Shanghai, Guangzhou and Xi'an.
  
  
  METHODS
  Daily health and meteorological data (including ambient temperature and relative humidity) were collected in the past several years. For the relative risk of PM2.5 effects on mortalities, generalized additive model (GAM) was used to obtain the exposure-response coefficients between PM2.5 and non-accidental mortalities after controlling time trend, week effects and meteorological factors. Then excess mortalities were calculated according to coefficients, health data and air pollution level.
  
  
  RESULTS
  The relative risks of PM2.5 effects on mortalities were 1.0027(1.0010-1.0044), 1.0020 (1.0007-1.0033) , 1.0056 (1.0022-1.0091), 1.0036 (1.0011-1.0061) for Beijing, Xi'an, Shanghai, Guangzhou respectively. Compared with relative risks in northern cities (Beijing and Xi'an), relative risks in southern cities (Shanghai and Guangzhou) were higher. The numbers of excess mortalities caused by PM2.5 in Beijing, Shanghai, Guangzhou, Xi'an were 2349, 2980, 1715, 726 and accounted for 1.9%, 1.6%, 2.2% and 1.6% of the total death number in 2010 respectively.
  
  
  CONCLUSIONS
  Although relative health risks caused by PM2.5 vary geographically for urban residents, public health is endangered. More efforts should be devoted to reducing PM2.5 pollution.
authors.affiliation: Department of Occupational & Environmental Health, School of Public Health, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Guo-xing
authors.initials: GX
authors.lastname: Li
authors.affiliation: Department of Occupational & Environmental Health, School of Public Health, Peking University Health Science Center, Beijing 100191, China. Email: xcpan@bjmu.edu.cn.
authors.forename: Xiao-chuan
authors.initials: XC
authors.lastname: Pan
mesh_terms: D000397:Air Pollution / Q000009:adverse effects*; D002681:China; D002947:Cities; D004781:Environmental Exposure / Q000009:adverse effects*; D006801:Humans; D009026:Mortality