CHENNAI: Koyambedu, the nerve centre of the city's vegetable, fruit and flower supply, and the nodal point for inter-state buses, trucks and lorries will come under the scanner of the Tamil Nadu Pollution Control Board (TNPCB).

The board has decided to establish a continuos, online pollution monitoring station in the area. "Although the city's industrial and residential centres such as Manali, Royapuram and IIT Madras are already under continuos online monitoring, this is the first time that a commercial-cum-residential locality is coming under the study," said Marimuthu, director of TNPCB. "We have floated tenders for the Rs 1 crore, 24-hour continuous monitoring project, which is part of the National Ambient Monitoring Programme (NAMP) " he said.

Koyambedu is also the hub of major infrastructure projects, with works on a flyover and the Metro Rail currently underway. Thousands of vehicles pass through the locality everyday, and the additional impact of the civic works will help in developing critical data. While vehicles are known to emit particulate matter due to incomplete or imperfect fuel combustion, the impact of civic works on the air quality and on people's health can be studied afresh.

Data made available by the transport department reveal that the daily average traffic at Koyambedu includes 15,000 trucks and lorries, 2500 moffusil buses, 1500 two wheelers which arrive at the market alone, 250 omni buses, 250 pre-paid auto rickshaws and thousands of private cars. "The air we breathe contains various chemical compounds due to activity on the ground, and this air will be supplied to various instruments in the monitor with defined flow rate. The components will reach different distribution points and will be measured against international parametres," an official explained.

Three continuos monitoring stations are currently functioning at Manali, Kathivakkam and Royapuram, but this is the first time that a market place adjoining a bus terminal would be monitored. There are four major components in the Continuous Ambient Air Quality Monitoring system - analysers, data management system, calibration system and data display system. The parameters that would be measured using a variety of techniques, include particulate matter, oxides of nitrogen, sulphur dioxide, ozone, carbon monoxide, benzene, toluene and xylene, temperature, relative humidity, solar radiation, wind speed and direction.

The TNPCB has acquired two shop floors from CMDA at the Koyambedu market for installating the monitoring system. Contracts would be awarded for a three year period on a own and maintain basis. The station should be operational by the third quarter of this year, an official said.