| Air quality standards (mg/m3) | | Source: M. Walsh, Motor Vehicle Pollution Control in the Asia Pacific Region. Numbers in parenthesis are previous standards |
|
Class I
|
Class II
|
Class III
|
US
|
|
SO2
|
annual ave.
|
0.02
|
0.06
|
0.1
|
0.08
|
|
daily ave.
|
0.05
|
0.15
|
0.25
|
0.365
|
|
1 hr
|
0.15
|
0.5
|
0.7
|
|
|
TSP
|
annual ave.
|
0.08
|
0.2
|
0.3
|
|
daily ave.
|
0.12
|
0.3
|
0.5
|
|
PM10
|
annual ave.
|
0.04
|
0.1
|
0.15
|
0.05
|
|
daily ave.
|
0.05
|
0.15
|
0.25
|
0.15
|
|
PM2.5
|
annual ave.
|
|
0.15
|
|
daily ave.
|
|
0.65
|
|
NO2
|
annual ave.
|
0.04
|
0.08(.04)
|
0.08
|
0.1
|
|
daily ave.
|
0.08
|
0.12(.08)
|
0.12
|
|
|
1 hr
|
0.12
|
0.24(.24)
|
0.24
|
|
CO
|
daily ave.
|
4
|
4
|
4
|
|
8 hr
|
|
10
|
|
1 hr
|
10
|
10
|
10
|
40
|
|
O3
|
1 hr
|
0.12
|
0.16
|
0.2
|
0.235
|
|
8 hr
|
|
0.157
|
|
|
|
| | Air Quality in Chinese Cities |
|
|
