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Table 3 Distributions of air pollutants among urbanization zones

From: Long-term exposure to air pollution and the risk of developing sudden sensorineural hearing loss

Pollutants Levels Highly Urbanized (n = 22,054) Moderately Urbanized (n = 22,975) Boomtown
(n = 10,896)
Others
(n = 10,396)
p Total
(n = 64,321)
PM2.5 (μg/m3) Mean (SD) 32.71 (7.85) 35.68 (9.16) 37.24 (8.44) 34.86 (9.04)  < 0.001 34.79 (8.75)
  Low 9906 44.9 6335 30.2 2651 24.3 2593 24.9  < 0.001 21,485 33.4
  Moderate 7680 34.8 6067 28.9 3538 32.5 3050 29.3   20,335 31.6
  High 4468 20.3 8573 40.9 4707 43.2 4753 45.7   22,501 35.0
SO2 (ppb) Mean (SD) 4.88 (2.09) 5.23 (2.53) 5.76 (2.74) 3.86 (1.97)  < 0.001 4.98 (2.41)
  Low 7275 33.0 6100 29.1 2700 24.8 5693 54.8  < 0.001 21,768 33.8
  Moderate 6833 31.0 6737 32.1 3233 29.7 2999 28.8   19,802 30.8
  High 7946 36.0 8138 38.8 4963 45.5 1704 16.4   22,751 35.4
CO (ppm) Mean (SD) 0.81 (0.30) 0.69 (0.24) 0.70 (0.22) 0.59 (0.21)  < 0.001 0.72 (0.27)
  Low 5516 25.0 7839 37.4 3492 32.0 5859 56.4  < 0.001 22,706 35.3
  Moderate 4810 21.8 6904 32.9 4534 41.6 3087 29.7   19,335 30.1
  High 11,728 53.2 6232 29.7 2870 26.3 1450 13.9   22,280 34.6
NO (ppb) Mean (SD) 14.14 (12.66) 9.94 (8.21) 10.73 (8.43) 6.80 (6.75)  < 0.001 11.01 (10.15)
  Low 4156 18.8 7342 35.0 3177 29.2 7198 69.2  < 0.001 21,873 34.0
  Moderate 6556 29.7 7551 36.0 4205 38.6 1937 18.6   20,249 31.5
  High 11,342 51.4 6082 29.0 3514 32.3 1261 12.1   22,199 34.5
NO2 (ppb) Mean (SD) 24.58 (6.51) 22.06 (6.30) 23.39 (5.19) 18.43 (6.41)  < 0.001 22.56 (6.56)
  Low 4245 19.2 7283 34.7 2547 23.4 6041 58.1  < 0.001 20,116 31.3
  Moderate 6127 27.8 7354 35.1 4930 45.2 2974 28.6   21,385 33.2
  High 11,682 53.0 6338 30.2 3419 31.4 1381 13.3   22,820 35.5
  1. ppb: parts per billion; ppm: parts per million