AMBIENT AIR QUALITY STATUS IN DELHI

The ambient air quality as monitored by CPCB during 1999, shows reduction in levels of various pollutants in ambient air as compared to previous year. The reducing trend was observed with respect to carbon monoxide, nitrogen dioxide, lead, sulphur dioxide and suspended particulate matter at traffic intersection (ITO), industrial areas with respect to nitrogen dioxide and lead in residential areas. The reduction in pollutants is attributable to various measures initiated during past several years for control of vehicular pollution.

• At traffic intersection the annual lead level in ambient air has been decreased to 49 percent during year 1999 as compared to 1998 and about 79 percent as compared to year 1995, when unleaded petrol was introduced for the first time.

• In industrial and residential areas annual lead level has been reduced to 45 percent and 52 percent respectively as compared to year 1998. The significant reduction of lead in year 1999 may be attributed due to phasing out of leaded petrol from September 1998.

• The annual levels of carbon monoxide has been reduced to 22 percent as compared to 1998. This significant reduction may be due to advancement of implementation of Euro I norms, use of CNG vehicles and enforcement of India 2000 norms for four stroke two wheelers and two stroke two wheelers.

• Annual nitrogen dioxide level has been reduced to the extent of 3 to 7 percent. The reduction may be attributed to phasing out 0f 15 years old commercial vehicles w.e.f. 31^st December, 1998 and advancement of implementation of Euro I norms for petrol and diesel driven private four wheelers.

• Annual sulphur dioxide levels at Traffic intersection and industrial areas has been reduced to 20% and 3% respectively. The significant reduction at traffic intersections may be due to use of low sulphur diesel w.e.f. April, 98.

• Reduction in particulate matter at traffic intersection and industrial areas may be due to use of low sulphur diesel, phasing out 15 years old commercial vehicles, use of premix 2 T oil and use of CNG vehicles.