CHENNAI Aug. 14. While increasing industrial and automobile pollution has now become the subject of a United Nations Environmental Programme (UNEP) study, which reveals a haze over south Asia, cutting 10 per cent of sunlight, the Central Pollution Control Board (CPCB) and the Tamil Nadu Pollution Control Board (TNPCB) have prepared a draft on the air quality status and action plan to control air pollution in Chennai.

The report of the Chennai Ambient Air Quality Monitoring Programme of the TNPCB issued periodically shows very high levels of Respirable Dust Particles (RDP) and Particulate Matter (PM) at the T. Nagar and Vallalar Nagar traffic and commercial intersections.

The draft says traffic congestion in Chennai has steadily increased causing acute shortage of parking space and deterioration of air quality. Emissions from vehicles have been the major source of air pollution. The number of on-road vehicles in 2001 was over nine lakhs, with a carbon monoxide contribution of 88.4 thousand tonnes, hydro carbons - 44.23 thousand tonnes, 17.19 thousand tonnes of oxides of nitrogen (NOX) and 4.19 thousand tonnes of PM.

Of the vehicular sources of pollution, two-wheelers with two stroke engines contributed the maximum with the less visible unburnt and partially burnt PM while three-wheelers driven by two-stroke engines emitted high levels of carbon monoxide and hydrocarbons. Old buses emit high levels of PM and NOX.

The Ambient Air Quality Monitoring in Chennai carried under the National Air Quality Monitoring Programme (NAAQ) by the TNPCB and the National Environmental Engineering Research Institute (NEERI) has revealed a dip in sulphur dioxide (SO2) levels in 2001 from the measurements in 1999 and 2000 in residential areas. The SO2, nitrogen dioxide (NO2) and Respirable Dust Particulate Matter (RSPM) levels were lower in 2001 besides being lower than the annual average of the NAAQ during all the monitored years in residential and industrial areas.

The draft concluded that while PM levels had violated the NAAQS in residential areas, which was due to emission from vehicles, re-suspension of traffic dust and emission from industries, the level of SO2 and NO2 in Chennai was well within the national annual average. "One reason for lower levels of pollution in Chennai compared to the national average was that it was a coastal city with excellent ventilation effect due to sea breeze".

In an action plan for controlling air pollution, the draft has suggested tighter emission norms, mandatory emission check, improvement of fuels, checking fuel adulteration and introduction of alternate fuels such as CNG or LPG. While supply of CNG was not possible in Chennai, oil companies were requested to supply LPG.

It has also suggested improvement of the public transport system to discourage use of private vehicles, upgradation of private emission testing centres for computerised emission checks and periodic inspection of in-use vehicles.

Traffic engineering suggestions include introduction of synchronised signals with timers, provision of bicycle pathways, bus-only lanes, ring roads to avoid inter-city vehicle entry into Chennai and regulation of traffic during peak hours.

In the proposed action plan for control of emissions, it was suggested that the Transport Department should inventorise vehicles based on technology and fuel, notify emission norms and prescribed smoke density standards for petrol vehicles.

Public transport needs more high capacity bus systems, light rail systems to accommodate more people than buses among others. Officials said the action to fight air pollution called for a co-operative effort from several Government departments and fiscal reforms.