title: Effect of the interaction between outdoor air pollution and extreme temperature on daily mortality in Shanghai, China.
abstract: BACKGROUND
  Both outdoor air pollution and extreme temperature have been associated with daily mortality; however, the effect of their interaction is not known.
  
  
  METHODS
  This time-series analysis examined the effect of the interaction between outdoor air pollutants and extreme temperature on daily mortality in Shanghai, China. A generalized additive model (GAM) with penalized splines was used to analyze mortality, air pollution, temperature, and covariate data. The effects of air pollutants were stratified by temperature stratum to examine the interaction effect of air pollutants and extreme temperature.
  
  
  RESULTS
  We found a statistically significant interaction between PM₁₀/O₃ and extreme low temperatures for both total nonaccidental and cause-specific mortality. On days with "normal" temperatures (15th-85th percentile), a 10-µg/m³ increment in PM₁₀ corresponded to a 0.17% (95% CI: 0.03%, 0.32%) increase in total mortality, a 0.23% (0.02%, 0.44%) increase in cardiovascular mortality, and a 0.26% (-0.07%, 0.60%) increase in respiratory mortality. On low-temperature days (<15th percentile), the estimates changed to 0.40% (0.21%, 0.58%) for total mortality, 0.49% (0.13%, 0.86%) for cardiovascular mortality, and 0.24% (-0.33%, 0.82%) for respiratory mortality. The interaction pattern of O₃ with lower temperature was similar. The interaction between PM₁₀/O₃ and lower temperature remained robust when alternative cut-points were used for temperature strata.
  
  
  CONCLUSIONS
  The acute health effects of air pollution might vary by temperature level.
authors: Department of Hematology, Fourth Affiliated Hospital of Nantong University, First Hospital of Yancheng, Yancheng, China.
authors: Yuexin
authors: Y
authors: Cheng
authors: Haidong
authors: H
authors: Kan
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D002318:Cardiovascular Diseases / Q000209:etiology / Q000401:mortality*; D002423:Cause of Death / Q000639:trends; D002681:China / Q000453:epidemiology; D055873:Extreme Cold / Q000009:adverse effects*; D006801:Humans; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D010126:Ozone / Q000032:analysis / Q000633:toxicity*; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity*; D012120:Respiration Disorders / Q000209:etiology / Q000401:mortality*; D013458:Sulfur Dioxide / Q000032:analysis / Q000633:toxicity; D013997:Time Factors
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D013458:Sulfur Dioxide; D010126:Ozone; D009585:Nitrogen Dioxide