Reanalysis of the association between reduction in long-term PM2.5 concentrations and improved life expectancy

Table 1 Summary statistics of average PM_2.5 concentrations (μg/m³) in 51 Metropolitan Statistical Areas (MSAs) based on measurements from regulatory monitoring networks (Inhalable Particulate Network (IPN) or Federal Reference Method (FRM)), and in 211 counties or 51 MSAs based on estimates by the historical prediction model for 1979–1983 and 1999–2000

Period	Exposure assessment	PM_2.5
Period	Exposure assessment	Min	Median	Max	Mean^c	SD
1979–1983	Measurement (IPN)^a: MSA average	10.77	20.81	30.01	20.62	4.36
	Census tract prediction: MSA average	10.61	18.46	24.84	17.85	2.42
	Census tract prediction: county average	9.73	18.09	24.84	17.85	2.89
	National grid prediction: MSA average	5.14	17.12	23.00	16.29	3.32
	National grid prediction: county average	3.66	16.92	24.77	16.29	3.75
1999–2000	Measurement (FRM)^b: MSA average	5.80	14.50	20.20	14.10	2.86
	Census tract prediction: MSA average	5.90	13.51	19.77	12.90	2.65
	Census tract prediction: county average	5.54	12.94	19.77	12.90	2.82
	National grid prediction: MSA average	3.00	12.79	16.93	11.95	3.11
	National grid prediction: county average	2.32	12.36	19.62	11.95	3.28

^a Inhalable Particulate Network
^b Federal Reference Method
^c MSA and county averages appear the same due to rounding; 1979–1983 IPN values differ slightly from Pope et al. (2009) due to rounding

ISSN: 1476-069X