Table 1 Contribution of bus commute to daily exposure of PM2.5 mass and elements.

From: Personal exposures to traffic-related air pollution in three Canadian bus transit systems: the Urban Transportation Exposure Study

Element

Mean (SD) % contributiona

Toronto (n = 18)

Ottawa (n = 18)

Vancouver (n = 17)

PM2.5

6 (2)

13 (10)

11 (4)

Al

26 (11)

32 (23)

38 (15)

As

7 (3)

5 (3)

8 (2)

Ba

59 (15)

60 (20)

57 (18)

Cd

8 (7)

10 (9)

–

Cr

27 (21)

19 (18)

–

Co

–

–

21 (9)

Cu

30 (15)

37 (9)

32 (7)

Fe

70 (19)

64 (15)

70 (15)

Mn

27 (14)

23 (13)

18 (9)

Mo

17 (12)

24 (7)

22 (6)

Ni

15 (11)

22 (16)

14 (9)

Pb

12 (6)

10 (5)

18 (13)

Sb

12 (4)

10 (6)

36 (10)

Se

4 (2)

–

–

Sn

17 (4)

19 (8)

–

Sr

20 (9)

26 (15)

24 (9)

Ti

39 (14)

41 (19)

–

V

6 (2)

8 (5)

13 (6)

Zn

10 (9)

12 (11)

8 (2)

  1. Full table can be found in Supplementary (S8A, B, C).
  2. aPercent contribution of 66-min bus commute (4.6% of day) to overall daily exposure (Eq. 1).
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