Do Cold Weather and Fine Particulate Matter Air Pollution Cause Early Deaths in the Elderly?

As discussed in Chap. 7, in 2011, the United States EPA projected that further reducing levels of fine particulate matter (PM2.5) will significantly extend life expectancy in the United States (EPA 2011). Similarly, Fann et al. (2012) estimated that “about 80,000 premature mortalities [per year] would be avoided by lowering PM2.5 levels to 5 μg/m3 nationwide” and that 2005 levels of PM2.5 cause about 130,000 premature mortalities per year among people over age 29, with a simulation-based 95 % confidence interval of 51,000–200,000. Likewise, a recent, influential, NASA-led study of the computer-predicted benefits of measures to combat global warming concluded that 0.7–4.7 million premature deaths per year would be avoided (and increases in temperatures would be moderated) in the near term by further reducing pollutants such as black carbon emissions (Shindell et al. 2012). Pope et al. (2009) concluded from a regression model of the association between reductions in pollution and changes in life expectancy in 211 county units in the USA that “A decrease of 10 μg per cubic meter in the concentration of fine particulate matter was associated with an estimated increase in mean (±SE) life expectancy of 0.61 ± 0.20 year (P = 0.004).” They interpreted the statistical regression coefficient causally, as implying that “A reduction in exposure to ambient fine particulate air pollution contributed to significant and measurable improvements in life expectancy in the United States,” although without reporting results of any formal statistical tests of this causal interpretation, for example, using the methods discussed in Chap. 1 and Bauwens et al. (2006).