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Table 3 Correlation among air pollutants

From: Effect of hourly concentration of particulate matter on peak expiratory flow in hospitalized children: A panel study

  Correlation coefficient
  Morning Noon Evening Night
  (6 a.m. through 7 a.m.) (12 p.m. through 1 p.m.) (6 p.m. through 7 p.m.) (12 a.m. through 1 a.m.)
PM2.5 - Ox -0.44 -0.24 -0.27 -0.40
NO2 - PM2.5 0.54 0.78 0.62 0.56
Ox - NO2 -0.74 -0.53 -0.68 -0.72
  1. PM2.5: Particulate matter with a 50% cut-off of aerodynamic diameter ≤2.5 μm
  2. NO2: Nitrogen dioxide
  3. Ox: Photochemical oxidants