The Hindu : Tamil Nadu News : Mapping ground ozone levels in Chennai

Online edition of India's National Newspaper
Friday, May 06, 2005

Tamil Nadu

Tamil Nadu

Mapping ground ozone levels in Chennai

Vani Doraisamy

IIT-M begins 3-year project to test efficacy of new emission norms

CHENNAI: The Indian Institute of Technology, Madras (IITM) has started a three-year project to map ground ozone levels in Chennai, as part of a pan-Asian initiative at urban environmental management. One of the objectives is to test the efficacy of the new emission control norms for automobiles.

The Swedish-funded Asian Regional Environmental Programme is co-ordinated by the Asian Institute of Technology, Bangkok and is being carried out simultaneously in six Asian cities — Chennai, Bangkok, Manila, Bandung, Hanoi and Beijing.

Apart from air pollution monitoring, solid waste management and wastewater harnessing are other aspects under study. In Chennai, as part of the air monitoring initiative, the Departments of Mechanical Engineering and Civil Engineering, IIT-M will jointly do the ozone mapping.

Ground ozone, mostly a result of photochemical smog caused by vehicular emissions containing hydrocarbons and oxides of nitrogen (NOX), is present till a height of 10 metres above ground level. Unlike atmospheric ozone that impacts humans through climate change, ground ozone is mildy corrosive and has direct health effects like eye, respiratory tract and skin irritation. Also, it affects UV radiation reaching the earth and adversely impacts ground vegetation. Ground ozone levels are maximum during heavy vehicular traffic and shoot up during peak hours.

Depending on the intensity of traffic, ground ozone concentration fluctuates throughout the day.

Along with ground ozone, IIT-M will also monitor sulphur dioxide and oxides of nitrogen being emitted by vehicles in various stations around the city.

Preliminary tests done by the Department of Chemical Engineering had shown that while oxides of sulphur (SOX) levels were under control, NOX levels had shot up. Also, particulate matter emissions — especially PM10 and the finer microned PM 2.5 — were higher than acceptable standards, especially in high-traffic areas such as T Nagar and Parry's Corner and industrial areas like Ambattur and Manali.

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