Air Quality
Air is all pervasive. Clean Air is a right which cannot be taken for granted. The air in most Indian cities is severely polluted and this has a serious impact on the health of populations. Unbridled natural pollutants, industrialization and increased reliance on fuel based means of transport, lack of mass transport facilities and the burning of bio-fuels in rural house holds has let a rapid deterioration of indoor and outdoor air quality. Suspended Particulate Matter appears to be the critical factor with levels much higher than the prescribed standards. In urban centers monitored by the CPCB while S.P.M was beyond standards, SO2 and NOx were within limits.
Air Quality Standards
This nation-wide programe was initiated in 1984. As on March 31, 1995, the network comprised 290 stations covering over 90 towns/cities distributed over 24 States and 4 Union Territories. The National Ambient Air Quality Monitoring (NAAQM) network is operated through the respective States Pollution Control Boards, the National Environmental Engineering Research Institute (NEERI), Nagpur and also through the CPCB.
The pollutants monitored are Sulphur dioxide (SO2), Nitrogen dioxide (NO2) and Suspended Particulate Matter (SPM) besides the meteorological parameters, like wind speed & direction, temperature and humidity. In addition to the three conventional parameters, NEERI monitors special parameters, like Ammonia (NH3), Hydrogen Sulphide (H2S), Respirable Suspended Particulate Matter (RSPM) and Polyaromatic Hydrocarbons (PAH).
Based on Annual Mean Concentration (microgram per cubic meter of ambient air) of SO2, NO2 and SPM and the Notified Ambient Air Quality Standards, the Ambient Air Quality Status is described in terms of Low (L), Moderate (M), High (H) and Critical (C) for Industrial (I), Residential and mixed use (R) areas of Cities/Towns in different States/UTs.
National Ambient Air quality Standards (NAAQS)
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POLLUTANTS
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Time Weighted Average
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Concentration of Ambient Air
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Industrial Area
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Residential Rural and other area
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Sensitive area
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Method of Measurement
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Sulphur Dioxide (SO2)
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Annual Average
24 hours
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80g/m3
120g/m3
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60g/m3
80�g/m3
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15g/m3
30g/m3
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Improved west and Gacke Method
Ultraviolet fluorescence
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Oxides of Nitrogen (NO2)
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Annual Average
24 hours
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80g/m3
120g/m3
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60g/m3
80g/m3
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15g/m3
30g/m3
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Jacab Hochheister modified (Na-Arsentire method
Gas Phase Chemilumine Scene
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Suspended Particulate Matter (SPM)
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Annual Average
24 hours
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360g/m3
500g/m3
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140g/m3
200g/m3
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70g/m3
100g/m3
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High Volume sampling (average flow rate not less than 1.1 m3/minute)
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Respirable Particulate Matter (size Less than 10�m) RPM
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Annual Average
24 hours
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120g/m3
150g/m3
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60g/m3
100g/m3
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50g/m3
75g/m3
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Respirable particulate matter sampler
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Lead as Pb
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Annual Average
24 hours
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1.0g/m3
1.5g/m3
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0.75g/m3
1.0g/m3
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0.50g/m3
0.75g/m3
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AAS method after sampling using EPM 2000 or equivalent filter paper
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Carbon Monoxide
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8 hours
1 hour
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5.0mg/m3
10.0mg/m3
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2.0mg/m3
4.0mg/m3
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1.0mg/m3
2.0mg/m3
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Non disbersive infrared spectroscopy
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Annual Average : Annual Arithmetic Mean of minimum 104 measurements in a year taken twice a week 24-hourly at uniform interval
24 Hours Average: 24-hourly/8-hourly values should be met 98% of the time in a year. However 2% of the time, it may exceeded but not two consecutive days.
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- The levels of air quality necessary with an adequate margin of safety, to protect the public health, vegetation and property.
- Whenever and wherever two consecutives values exceeds the limit specified above for the respective category, it shall be considered adequate, reason to institute regular / continuous monitoring and further investigations.
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Source: http://www.cpcb.nic.