Table 2

Meta-analysis results for mortality in all ages associated with a 10 µg/m3 increase in NO2

WHO regionNO2 24 hNO2 1 h
All SC/MC*Selected SC/MC†Random effects (95% CI)‡I2 (%)§All SC/MC*Selected SC/MC†Random effects (95% CI)‡I2 (%)§
All-cause, all ages
Overall¶72/125/60.71 (0.43 to 1.00)61.820/33/20.24 (0.00 to 0.49)88.2
 AMR A11/51/20.32 (−0.01 to 0.67)2/02/00.76 (−0.05 to 1.58)
 AMR B1/01/00.59 (−0.26 to 1.45)2/02/0−0.06 (−0.13, 0.01)
 EUR A40/614/30.90 (0.45 to 1.35)14/23/10.25 (0.10 to 0.40)
 WPR A3/03/00.66 (−0.10 to 1.44)2/10/10.58 (0.21 to 0.94)
 WPR B17/06/00.56 (0.18 to 0.94)
 Multiregion**0/10/11.23 (0.84 to 1.62)
All cardiovascular, all ages
Overall¶54/85/50.88 (0.63 to 1.13)72.713/21/20.85 (0.20 to 1.50)0
 AMR A5/14/10.53 (0.38 to 0.67)
 AMR B1/01/00.73 (−0.87 to 2.36)
 EUR A30/610/31.03 (0.70 to 1.36)12/12/11.02 (−0.44 to 2.49)
 WPR A1/01/00.67 (−0.24 to 1.60)1/10/10.94 (0.42 to 1.47)
 WPR B17/07/00.91 (0.52 to 1.31)
 Multiregion**0/10/11.36 (0.89 to 1.83)
All respiratory, all ages
Overall¶49/85/51.09 (0.75 to 1.42)14.716/31/21.02 (−0.37 to 2.44)87.4
 AMR A4/13/10.54 (−0.02 to 1.10)
 AMR B1/01/01.21 (−1.43 to 3.91)
 EUR A29/69/31.32 (0.74 to 1.91)14/22/10.38 (0.17 to 0.59)
 WPR A3/03/01.27 (−0.86 to 3.45)2/10/12.00 (0.89 to 3.12)
 WPR B12/05/01.49 (0.47 to 2.52)
 Multiregion**0/10/11.48 (0.68 to 2.29)
  • *Numbers of SC/MC estimates available from all studies.

  • †Numbers of SC/MC estimates selected for meta-analysis.

  • ‡Random-effects summary estimate (95% CI) per 10 μg/m3 increase in NO2.

  • §I2 statistic for heterogeneity between WHO regions.

  • ¶Estimate numbers for ‘overall’ refer to: (1) the number of SC/MC estimates available from all studies; (2) for selected estimates, it is the number of pooled (from SC estimates) and MC estimates used to calculate the overall summary estimate across WHO regions.

  • **Multiregion refers to more than one WHO region. In this table, only one MC study (RMID 313) provided estimates for WHO multiregion for mortality; the WHO regions covered in this study were SEAR B and WPR B.

  • AMR, Region of the Americas; EUR, European Region; MC, multicity; SC, single-city; SEAR, South East Asian Region; WPR, Western Pacific Region.