Temperature modifies the association between particulate air pollution and mortality: A multi-city study in South Korea

• Published in: The Science of the total environment Vol. 524-525; pp. 376 - 383
• Main Authors: Kim, Satbyul Estella, Lim, Youn-Hee, Kim, Ho
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15-08-2015
• Subjects: Adult; Aged; Air Pollutants; Air pollution; Air Pollution - statistics & numerical data; Cardiovascular Diseases - mortality; Cities; Effect modification; Environmental Exposure - statistics & numerical data; Female; Humans; Male; Middle Aged; Mortality; Particulate matter; Particulate Matter - analysis; Republic of Korea - epidemiology; Respiratory Tract Diseases - epidemiology; Temperature; Time-series studies; Young Adult; Republic of Korea; Effect modification; Air pollution; Time-series studies; Temperature; Particulate matter; Mortality
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2015.03.137

Substantial epidemiologic literature has demonstrated the effects of air pollution and temperature on mortality. However, there is inconsistent evidence regarding the temperature modification effect on acute mortality due to air pollution. Herein, we investigated the effects of temperature on the relationship between air pollution and mortality due to non-accidental, cardiovascular, and respiratory death in seven cities in South Korea. We applied stratified time-series models to the data sets in order to examine whether the effects of particulate matter <10μm (PM10) on mortality were modified by temperature. The effect of PM10 on daily mortality was first quantified within different ranges of temperatures at each location using a time-series model, and then the estimates were pooled through a random-effects meta-analysis using the maximum likelihood method. From all the data sets, 828,787 non-accidental deaths were registered from 2000–2009. The highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on extremely hot days (daily mean temperature: >99th percentile) in individuals aged <65years. In those aged ≥65years, the highest overall risk between PM10 and non-accidental or cardiovascular mortality was observed on very hot days and not on extremely hot days (daily mean temperature: 95–99th percentile). There were strong harmful effects from PM10 on non-accidental mortality with the highest temperature range (>99th percentile) in men, with a very high temperature range (95–99th percentile) in women. Our findings showed that temperature can affect the relationship between the PM10 levels and cause-specific mortality. Moreover, the differences were apparent after considering the age and sex groups.
•Effect modification of temperature on the air pollution-mortality was investigated.•Cause-specific death, age and sex categories were explored.•Strongest association was seen for the younger (age <65) or men during very hot days.•Strongest association was seen for the older (age≥65) or women during hot days.•Modification patterns were different by the cause of death, age and sex.