title: Modification of the effects of air pollutants on mortality by temperature: A systematic review and meta-analysis.
abstract: Temperature extremes and air pollution both pose significant threats to human health, but it remains uncertain whether pollutants' effects on mortality are modified by temperature levels. In this review, we summarized epidemiologic evidence on the modification by temperature of the acute effects of air pollutants on non-accidental and cardiovascular mortality. The EMBASE, PubMed, ProQuest Dissertations and Theses, and Elsevier Science Direct databases were used to identify papers published up to 2nd December 2014. Studies with appropriate design, exposures and outcome indicators, quantitative estimates and high/intermediate quality were included. Twenty-one studies met the inclusion criteria, of which 12 reported the effects of PM10on mortality modified by temperature, 10 studied O3, and the rest examined NO2, SO2, PM2.5,PM10-2.5, CO and black smoke. We divided temperature into low, medium, and high categories as defined in each study. In high temperature days, a 10μg/m3increment in PM10concentration corresponded to pooled estimates of 0.78% (95% CI: 0.44%, 1.11%) and 1.28% (0.66%, 1.91%) increase in non-accidental and cardiovascular mortality, both statistically significantly higher than the estimates in medium temperature stratum. Pooled effects of O3on non-accidental mortality on low and high temperature days were increases of 0.48% (0.28%, 0.69%) and 0.47% (0.32%, 0.63%) respectively, for 10μg/m3increase in exposure, both significantly higher than the increase of 0.20% (0.07%, 0.34%) on medium temperature days. The effect of O3on cardiovascular mortality was strongest on high temperature days with pooled estimate of 1.63% (1.14%, 2.13%). No significant interactions between SO2/NO2and temperature were detected by meta-analysis. Other pollutants were not analyzed due to the lack of suitable studies. In summary, we observed interactions between high temperature and PM10and O3in the effects on non-accidental and cardiovascular mortality. Low temperature modified the effects of air pollutants but not in a consistent fashion: the effect of PM10oncardiovascular mortality was diminished but the association between O3and non-accidental mortality was strengthened.
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; Changping District Centre for Disease Control and Prevention, Beijing 102200, China. Electronic address: lijing986169323@sina.cn.
authors: Jing
authors: J
authors: Li
authors: School of Population Health, University of Auckland, Auckland, New Zealand. Electronic address: a.woodward@auckland.ac.nz.
authors: Alistair
authors: A
authors: Woodward
authors: School of Public Health and Social Work, Queensland University of Technology, Brisbane, Queensland, Australia. Electronic address: x.hou@qut.edu.au.
authors: Xiang-Yu
authors: XY
authors: Hou
authors: College of Environmental Science and Engineering Director, Centre for Environment and Health, Peking University, Beijing 100871, China. Electronic address: tzhu@pku.edu.cn.
authors: Tong
authors: T
authors: Zhu
authors: State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China. Electronic address: zhangjl@craes.org.cn.
authors: Jinliang
authors: J
authors: Zhang
authors: Campden BRI (Chipping Campden) Limited - part of the Campden BRI group, Chipping Campden, Gloucestershire, UK. Electronic address: H.Brown@exchange.curtin.edu.au.
authors: Helen
authors: H
authors: Brown
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China. Electronic address: smart_yjun@163.com.
authors: Jun
authors: J
authors: Yang
authors: School of Population Health, University of Auckland, Auckland, New Zealand. Electronic address: rennie.qin@gmail.com.
authors: Rennie
authors: R
authors: Qin
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China. Electronic address: gaojinghong2007@126.com.
authors: Jinghong
authors: J
authors: Gao
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China. Electronic address: gushaohua1989@126.com.
authors: Shaohua
authors: S
authors: Gu
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; Department of Epidemiology, School of Public Health, Shandong University, Jinan 250012, China. Electronic address: lijingsddx@126.com.
authors: Jing
authors: J
authors: Li
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China. Electronic address: xulei@icdc.cn.
authors: Lei
authors: L
authors: Xu
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China. Electronic address: liuxiaobo@icdc.cn.
authors: Xiaobo
authors: X
authors: Liu
authors: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, China; Climate Change and Health Center, Shandong University, Jinan 250012, China. Electronic address: liuqiyong@icdc.cn.
authors: Qiyong
authors: Q
authors: Liu
mesh_terms: D000393:Air Pollutants / Q000009:adverse effects*; D000397:Air Pollution / Q000009:adverse effects; D016208:Databases, Factual; D006358:Hot Temperature; D006801:Humans; D009026:Mortality; D052638:Particulate Matter; D013696:Temperature
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
keywords: Air pollution; Extreme temperature; Meta-analysis; Modification; Mortality; Systematic review