Table 6 Estimated reduction of overall bus riding exposures with replacement of 1983–2003 buses with hybrid diesel/electric buses.

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

Pollutant

City

Bus riding exposures (mean (SD))

Estimated % reduction of riding exposures with fleet changeover

Sampled fleet

With replacement of 1983–2003 buses

PM2.5 (µg/m3)

Toronto

22.5 (9.9)

21.3 (9.9)

6.3 (5.2)

Ottawa

24.2 (12.6)

22.6 (11.4)

6.6 (4.8)

Vancouver

18.2 (5.5)

15.0 (4.8)

17.6 (7.5)

Ultrafine particles (103 pts/cm3)

Toronto

15.8 (4.4)

15.2 (4.3)

3.6 (3.1)

Ottawa

18.3 (8.6)

16.7 (8.6)

10.7 (7.6)

Vancouver

16 (12.0)

–

–

BC (µg/m3)

Toronto

3.1 (2.0)

3.0 (1.9)

4.6 (4.0)

Ottawa

2.6 (1.5)

2.1 (1.1)

12.7 (8.9)

Vancouver

2.6 (0.6)

2.4 (0.5)

9.9 (4.1)

  1. “–” denotes no evidence of lower UFP exposures in diesel/electric hybrids relative to the 1983–2003 class.
  2. aBased on estimates of % reduced exposure presented in Table 4.
Back to article page