Table 1
Changes in mean hourly HGV counts and particulate concentrations
Congested streets
Uncongested streets
1996–97
1998–99
Change
1996–97
1998–99
Change
HGVs per hour
74
39
−46.9%
PM
10
(μg/m
3
)
35.2
27.2
−22.7%
11.6
8.2
−28.9%
PM
2.5
(μg/m
3
)
21.2
16.2
−23.5%
6.7
4.9
−26.6%