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Table 2 Summary statistics for air pollutant and meteorological variables

From: Low level air pollution and exacerbation of existing copd: a case crossover analysis

Pollutant or meteorological variable (units)a

Minimum

Maximum

Mean ± St. dev

Mean as % of NAAQSb

PM2.5 (ug/m3)

0.45

37.0

8.56 ± 5.4

71 %

NO2 (ppb)

2.79

40.0

11.0 ± 5.0

21 %

SO2 (ppb)

0.28

7.51

1.99 ± 0.91

7 %

Relative Humidity (%)

22.4

93.9

68.7 ± 13.9

--

Temperature (°F)

0.96

83.8

49.8 ± 17.1

--

Temperature (°C)

−17.2

28.8

9.89 ± −8.3

 
  1. aAir pollutants: based on daily averages measured in Worcester, Ware and Springfield
  2. Temperature and humidity: based on daily averages from Worcester Regional Airport
  3. bRelevant USEPA National Ambient Air Quality Standards (NAAQS)
  4. PM2.5 = 12 ug/m3 annual mean, averaged over 3 years
  5. NO2 = 53 ppb annual mean
  6. SO2 = 30 ppb annual mean (based on USEPA 1971 value, which was revoked in 2010 and replaced with a 1-h maximum)
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Environmental Health

ISSN: 1476-069X