Table 2

Random-effects summary estimates (as percentage change (95% CIs)) for mortality or hospital admissions associated with a 10 µg/m3 increase 24 hour average pollution

All
SC/MC*
Selected
SC/MC (cities)†
24-hour NO224-hour PM
Single-pollutantAdjusted for PMSingle-pollutantAdjusted for NO2
All-cause mortality, all ages
 PM1013/34/1 (21)0.92 (0.58 to 1.72)0.85 (0.52 to 1.18)0.51 (0.29 to 0.74)0.18 (−0.11 to 0.47)
 PM2.52/32/1 (14)0.53 (0.42 to 0.64)0.57 (0.24 to 0.89)0.74 (0.34 to 1.14)0.54 (−0.25 to 1.34)
 PM10–2.50/30/1 (12)0.62 (0.19 to 1.06)0.73 (0.28 to 1.18)0.65 (−0.10 to 1.42)0.31 (−0.49 to 1.11)
 Visibility0/10/1 (12)0.60 (0.34 to 0.87)0.66 (0.33 to 1.00)40.93 (23.39 to 60.97)‡12.42 (−4.47 to 32.29)‡
All cardiovascular mortality, all ages
 PM1010/04/0 (8)0.99 (0.49 to 1.49)0.87 (0.28 to 1.46)0.48 (0.18 to 0.78)0.19 (−0.21 to 0.59)
All respiratory mortality, all ages
 PM107/02/0 (5)1.44 (0.63 to 2.27)1.15 (0.47 to 1.84)0.58 (0.22 to 0.93)0.13 (−0.18 to 0.44)
All respiratory hospital admissions, children (5–14 years)
 PM100/10/1 (5)5.95 (1.74 to 10.33)6.56 (3.08 to 10.17)
Cardiac hospital admissions, all ages
 PM102/12/1 (7)0.93 (0.46 to 1.40)0.75 (−0.13 to 1.64)
 BS0/10/1 (4)0.68 (0.17 to 1.20)0.36 (−0.65 to 1.38)
 TSP0/10/1 (6)1.03 (0.45 to 1.61)1.08 (0.43 to 1.72)
  • *Numbers of available pairs of single-city (SC)/multi-city (MC) estimates from all studies.

  • †Numbers of pairs of pooled (from single-city estimates) and multicity estimates used to calculate the overall summary estimate across WHO regions. Estimates were selected for meta-analysis from all those available. The number of cities represented by the summary estimates is given in brackets.

  • ‡The results for visibility (measured as coefficient of haze (COH units)) are not comparable to other PM results.

  • BS. Black Smoke; NO2, nitrogen dioxide; PM, particulate matter.