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Table 3 Correlation between air pollutant and meteorological variables

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

  SO2 a NO2 a PM2.5 a Temperatureb
NO2 a Spring: 0.14 -- -- --
Summer: −0.03
Fall: 0.52**
Winter: 0.80**
PM2.5 a Spring: 0.30** Spring: 0.41** -- --
Summer: 0.20* Summer: 0.45**
Fall: 0.39** Fall: 0.73**
Winter: 0.79** Winter: 0.83**
Temperatureb Spring: 0.34** Spring: 0.02 Spring: 0.52** --
Summer: 0.24** Summer: 0.15* Summer: 0.62**
Fall: 0.02 Fall: −0.04 Fall: −0.15*
Winter: −0.13 Winter: 0.09 Winter: 0.11
Relative Humidityb Spring: 0.09 Spring: 0.07 Spring: −0.01 Spring: −0.25**
Summer: −0.13 Summer: 0.02 Summer: −0.07 Summer: 0.22**
Fall: −0.14* Fall: −0.24** Fall: −0.28** Fall: 0.38**
Winter: −0.02 Winter: 0.03 Winter: 0.08 Winter: 0.22**
  1. Values shown are Pearson Correlation Coefficients; * indicates p < 0.05 and ** indicates p <0.0001
  2. a24-h average concentrations; Worcester, Ware and Springfield monitors from 2011 to 2012
  3. b24-h average measurements; Worcester Regional Airport meteorological site from 2011–2012