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Table 3 Associations between pollutant concentrations and pediatric asthma emergency department visits per unit increases in concentration.a

From: Implications of different approaches for characterizing ambient air pollutant concentrations within the urban airshed for time-series studies and health benefits analyses

  Central monitor Unweighted average Population-weighted average
Pollutant RR, 95% CI Chi-square, p-value RR, 95% CI Chi-square, p-value RR, 95% CI Chi-square, p-value
8-h ozone, per 25 ppb 1.061 (1.033, 1.090) χ2 = 18.89, p < 0.001 1.065 (1.036, 1.096) χ2 = 19.47, p < 0.001 1.070 (1.037, 1.104) χ2 = 17.68, p < 0.001
24-h PM10, per 10 μg/m3 1.018 (1.002, 1.034) χ2 = 4.82, p = 0.028 1.017 (1.001, 1.033) χ2 = 4.40, p = 0.036 1.016 (0.999, 1.033) χ2 = 3.31, p = 0.069
24-h PM2.5, per 10 μg/m3 1.031 (1.006, 1.057) χ2 = 6.08, p = 0.014 1.042 (1.014, 1.071) χ2 = 8.96, p = 0.003 1.044 (1.014, 1.075) χ2 = 8.28, p = 0.004
24-h PM2.5 sulfate, per 5 μg/m3 1.035 (1.003, 1.069) χ2 = 4.63, p = 0.031 1.042 (1.007, 1.077) χ2 = 5.64, p = 0.018 1.040 (1.005, 1.077) χ2 = 4.93, p = 0.026
24-h PM2.5 organic carbon, per 2 μg/m3 1.022 (0.997, 1.047) χ2 = 3.05, p = 0.081 1.031 (1.010, 1.053) χ2 = 8.39, p = 0.004 1.021 (1.003, 1.040) χ2 = 5.43, p = 0.020
24-h PM2.5 elemental carbon, per 1 μg/m3 1.028 (1.006, 1.051) χ2 = 6.22, p = 0.013 1.036 (1.008, 1.065) χ2 = 6.55, p = 0.010 1.065 (1.016, 1.116) χ2 = 6.97, p = 0.008
1-h nitrogen dioxide, per 20 ppb 1.052 (1.028, 1.077) χ2 = 17.98, p < 0.001 1.079 (1.044, 1.116) χ2 = 19.81, p < 0.001 1.105 (1.060, 1.152) χ2 = 22.30, p < 0.001
1-h carbon monoxide, per 1 ppm 1.044 (1.019, 1.070) χ2 = 12.71, p < 0.001 1.042 (1.015, 1.068) χ2 = 9.80, p = 0.002 1.096 (1.039, 1.156) χ2 = 11.32, p = 0.001
1-h sulfur dioxide, per 20 ppb 1.015 (0.998, 1.041) χ2 = 1.18, p = 0.277 1.062 (1.014, 1.111) χ2 = 6.60, p = 0.010 1.053 (1.004, 1.104) χ2 = 4.48, p = 0.034
  1. Abbreviations: interquartile range (IQR), rate ratio (RR), confidence interval (CI), hour (h), parts per billion (ppb), micrograms per cubic meter (μg/m3), parts per million (ppm).
  2. aRate ratios are for three-day moving average (average of lag 0, lag 1, and lag 2) pollutant concentrations during the six warmest months in Atlanta (May through October).