Table 1 Decreases in air pollutant concentrations are of similar magnitude in grid cells regardless of their clean fleet change category.

From: Clean fleets, different streets: evaluating the effect of New York City’s clean bus program on changes to estimated ambient air pollution

 

No bus service

At or below median clean shift

Above median clean shift

 

N = 3839

N = 2931

N = 2900

 

Mean (SD)

Mean (SD)

Mean (SD)

Bus Traffic

 Δ Clean VMT 2009-2014

 

4.1% (18.49%)

37.44% (11.4%)

 Clean VMT, 2009 (km)

 

1.5780e + 04 (2.0562e + 04)

7.9430e + 03 (1.3782e + 04)

 Clean VMT, 2014 (km)

 

2.1677e + 04 (2.6638e + 04)

2.1306e + 04 (2.4468e + 04)

 Total VMT, 2009 (km)

 

3.0730e + 04 (4.3848e + 04)

3.0540e + 04 (4.2462e + 04)

 Total VMT, 2014 (km)

 

3.4599e + 04 (4.2917e + 04)

3.4692e + 04 (3.9895e + 04)

 Number of bus stops

0.0049, (0.0806)

2.566 (2.4075)

2.859 (2.4077)

Other traffic sources

 Truck route present

9.74%

60.32%

70.34%

 Total traffic VMT (km)

2.6932e + 06, (7.5584e + 06)

1.0553e + 07 (1.3569e + 07)

7.8205e + 06 (1.1067e + 07)

Pollutant concentrations

 Δ NO 2009–2014 (ppb)

−3.0775 (1.5459)

−3.6815 (1.8919)

−4.1643 (2.5428)

 Δ NO2 2009–2014 (ppb)

−2.9695 (1.3797)

−4.1414 (1.5173)

−4.0518 (1.7431)

 Δ BC 2009–2014 (ppb)

−0.177 (0.0298)

−0.184 (0.0233)

−0.1774 (0.0322)

  1. Values representing a proportion are expressed as a percentage. Values representing a magnitude are expressed as mean (standard deviation) across all grid cells in each respective category. Clean fleet changes tend to co-occur with higher total traffic volume and presence of a truck route.
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