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Table 2 Level of personal PM 2.5 , elemental carbon (EC), and elemental components of PM 2.5 during work hours on the examination days a

From: Air pollution exposure and lung function in highly exposed subjects in Beijing, China: a repeated-measure study

  Office workers Truck drivers Mean exposure difference (95% CI)b
(observations = 120) (observations = 120)
  N Mean SD 10pct 25pct Median 75pct 90pct N Mean SD 10pct 25pct Median 75pct 90pct  
PM2.5 120 94.59 64.91 22.39 48.48 86.17 126.56 183.44 119 126.83 68.82 46.26 73.86 116.78 160.49 213.94 32.24 (15.19; 49.28)
EC 118 13.01 4.04 7.11 9.99 13.16 15.85 18.35 120 17.27 6.69 8.93 12.78 16.86 21.03 26.21 4.26 (2.84; 5.68)
K 118 0.76 0.77 0.18 0.27 0.56 0.82 2.07 120 1.31 1.07 0.34 0.44 0.89 2.06 2.81 0.55 (0.31; 0.79)
S 118 6.19 5.05 0.61 1.66 5.30 8.64 13.77 120 8.43 4.92 2.30 4.87 6.98 12.47 16.14 2.24 (0.97; 3.52)
Fe 118 0.38 0.21 0.17 0.24 0.34 0.44 0.69 120 1.01 0.64 0.38 0.50 0.82 1.34 1.75 0.63 (0.51; 0.75)
Si 118 0.79 0.53 0.28 0.45 0.68 1.03 1.43 120 2.37 1.76 0.64 0.82 2.09 3.54 4.13 1.58 (1.25; 1.91)
Al 118 0.54 0.25 0.23 0.37 0.50 0.70 0.86 120 1.36 0.93 0.44 0.59 1.29 1.86 2.32 0.82 (0.65; 0.99)
Zn 118 0.15 0.17 0.02 0.05 0.08 0.22 0.37 120 0.27 0.22 0.06 0.09 0.17 0.41 0.68 0.12 (0.07; 0.17)
Ca 118 0.32 0.18 0.15 0.19 0.28 0.41 0.54 120 2.09 2.2 0.29 0.4 1.58 3.08 4.52 1.76 (1.36; 2.17)
Ti 118 0.02 0.01 0.00 0.01 0.02 0.03 0.04 120 0.06 0.04 0.02 0.03 0.05 0.08 0.10 0.04 (0.03; 0.04)
  1. aMeasured during the work hours of examination days using light-weight personal monitors.
  2. bMean exposure levels of truck drivers – mean exposure levels of office workers.