Does temperature modify the association between air pollution and mortality? A multicity case-crossover analysis in Italy.

Department of Epidemiology, Rome E Health Authority, Rome, Italy.
American journal of epidemiology (Impact Factor: 4.98). 07/2008; 167(12):1476-85. DOI: 10.1093/aje/kwn074
Source: PubMed

ABSTRACT Adverse health effects of particulate matter <10 microm in aerodynamic diameter (PM(10)) and high temperatures are well known, but the extent of their interaction on mortality is less clear. This paper describes effect modification of temperature in the PM(10)-mortality association and tests the hypothesis that higher PM(10) effects in summer are due to enhanced exposure to particles. All deaths of residents of nine Italian cities between 1997 and 2004 were selected. The case-crossover approach was adopted to estimate the effect of PM(10) on mortality by season and temperature level. Three strata of temperature corresponding to low, medium, and high "ventilation" were identified, and the interaction between PM(10) and temperature within each stratum was examined. Season and temperature levels strongly modified the PM(10)-mortality association: for a 10-microg/m(3) variation in PM(10), a 2.54% increase in risk of death in summer (95% confidence interval: 1.31, 3.78) compared with 0.20% (95% confidence interval: -0.08, 0.49) in winter. Analysis of the interaction between PM(10) and temperature within temperature strata resulted in positive but, in most cases, nonstatistically significant coefficients. The authors found much higher PM(10) effects on mortality during warmer days. The hypothesis that such an effect is attributable to enhanced exposure to particles in summer could not be rejected.

Download full-text


Available from: Carlo A Perucci, Feb 02, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Meteorological (T and RH values) and air pollution data (PM10, NO2 and O3 concentrations) observed in Athens, Thessaloniki and Volos were analyzed to assess the air quality and the thermal comfort conditions and to study their synergy, when extreme hot weather prevailed in Greece during the period 2001–2010. The identification of a heat wave day was based on the suggestion made by the IPCC to define an extreme weather event. According to it, a heat wave day is detected when the daily maximum hourly temperature value exceeds its 90th percentile. This temperature criterion was applied to the data recorded at the cities center. Air quality was assessed at three sites in Athens (city center, near the city center, suburb), at two sites in Thessaloniki (city center, suburb) and at one site in Volos (city center), while thermal comfort conditions were assessed at the cities center. Mean pollution levels during the heat wave days and the non-heat wave days were calculated in order to examine the impact of the extreme hot weather on air quality. For this purpose, the distributions of the common air quality index and the exceedances of the air quality standards in force during the heat wave days and the non-heat wave days were also studied. Additionally, the variation of the daily maximum hourly value of Thom's discomfort index was studied in order to investigate the effect of extreme hot weather on people's thermal comfort. Moreover, the values of the common air quality index and Thom's discomfort index were comparatively assessed so as to investigate their synergy under extreme hot weather.
    Atmospheric Research 01/2015; 152:4–13. DOI:10.1016/j.atmosres.2014.06.002 · 2.42 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: It remains uncertain whether air pollution modifies the magnitude and time course of the temperature-mortality association. We applied a distributed lag non-linear model (DLNM) combined with non-linear interaction terms to assess the modifying effects of particulate matter with an aerodynamic diameter of 10 μm or less (PM10) on the association between mean temperature and mortality in Guangzhou, China. We found that both cold and hot effects increased with the quartiles of PM10. The elderly were more vulnerable to cold and hot effects. Men suffered more from cold-related mortality than women, with the gender difference enlarging with the quartiles of PM10. We identified statistically significant interaction effects between PM10 and mean temperature on mortality (except for respiratory mortality). Cold and hot effects basically appeared acutely on highly polluted days, while effects were delayed on lowly polluted days. The findings indicate the importance of reducing PM10 emission on extremely temperature days. Copyright © 2014 Elsevier Ltd. All rights reserved.
    Environmental Pollution 11/2014; xxx(2015):1-8. DOI:10.1016/j.envpol.2014.11.005 · 3.90 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Multicentric studies in Europe are required to gain knowledge on the short-term impacts of PM2.5 and PM10–2.5. We present an analysis of the short-term associations between particulate matters (PM10, PM10–2.5 and PM2.5) and mortality by causes, age-groups and seasons in nine French cities. Methods The associations between PM and daily mortality were investigated in each city using a generalized additive Poisson regression model for the 2000–2006 period. The percent increases in the mortality rate were estimated for a 10 μg/m3 increase and for an interquartile range increase in PM levels in each city, for the whole year and by season. The models also compared the PM effect observed on “non-warm” days and on “warm” days. Results A significant effect of PM10 (+0.8% CI 95% [0.2; 1.5] for a 10 μg/m3 increase) and PM2.5 (+0.7% [−0.1; 1.6]) on all-ages non-accidental mortality whole year was observed. The largest impacts were observed on all-ages cardiovascular mortality during summer for PM2.5 (+5.1% [1.8; 8.4]) and PM10–2.5 (+7.2% [2.8; 11.7]). These estimates were lowered when the model included PM2.5 and PM10–2.5. We also report a significant interaction between warm days and PM. Adjusting PM on ozone did not modify the results for the whole year, but decreased the estimates for summer, when a high correlation is observed between these pollutants. Conclusions Our results confirm the short-term impacts of PM10 on mortality, even at concentrations complying with the European annual regulation. They underline the short-term impacts of PM2.5 and PM10–2.5 and call for the setting of regulation values for these PM indicators.
    Atmospheric Environment 10/2014; 95:175–184. DOI:10.1016/j.atmosenv.2014.06.030 · 3.06 Impact Factor