National Ambient Air Quality Standards

Pollutants
Time weighted average
Concentration in ambient air
Industrial Area
Residential, Rural & other Areas
Sensitive Area
1
2
3
4
5
Sulphur Dioxide(SO2)
Annual Average*
80 µg/m3
60 µg/m3
15 µg/m3
24 hours****
120 µg/m3
80 µg/m3
30 µg/m3
Oxides of Nitrogen as NO2
Annual Average*
80 µg/m3
60 µg/m3
15 µg/m3
24 hours****
120 µg/m3
80 µg/m3
30 µg/m3
Suspended Particulate Matter (SPM)
Annual Average*
360 µg/m3
140 µg/m3
70 µg/m3
24 hours****
500 µg/m3
200 µg/m3
100 µg/m3
Respirable Particulate Matter (RPM) (size less than 10 microns)
Annual Average*
120 µg/m3
60 µg/m3
50 µg/m3
24 hours****
150 µg/m3
100 µg/m3
75 µg/m3
Lead
Annual Average*
1.0 µg/m3
0.75 µg/m3
0.50 µg/m3
24 hours****
1.5 µg/m3
1.0 µg/m3
0.75 µg/m3
Ammonia1
Annual Average*
0.1 mg/m3
0.1 mg/m3
0.1 mg/m3
 
24 hours****
0.4 mg/m3
0.4 mg/m3
0.4mg/m3
Carbon Monoxides
8 hours**
5.0 mg/m3
2.0 mg/m3
1.0 mg/m3
1 hours
10.0 mg/m3
4.0 mg/m3
2.0 mg/m3
*
Annual Arithmetic mean of minimum 104 measurements in a year taken twice a week 24 hourly at uniform interval.
**
24 hourly/ 8 hourly values should be met 98% of the time in a year. However, 2% of the time, it may exceed but not on two consecutive days.Annual Arithmetic mean of minimum 104 measurements in a year taken twice a week at uniform interval.

NOTE:

1. National Ambient Air Quality Standard: The levels of air quality with an adequate margin of safety, to protect the public health, vegetation and property.

2. Whenever and wherever two consecutive values exceeds the limit specified above for the respective category, it would be considered adequate reason to institute regular/ continuous monitoring and further investigation.

S.O. 384(E), Air (Prevention & Control of Pollution) Act, 1981, dated April 11, 1994] [EPA Notification: GSR 176(E), April 02, 1996].

1. Include vide Notification SO.955(E), Air (Prevention & Control of Pollution) Act, 1981, dated October 14, 1998]
 
 
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