High levels of CO2 found in Pallikaranai

Toxic hazeResidents said the burning was forcing many to leave the area—Photo: M. Karunakaran

Toxic hazeResidents said the burning was forcing many to leave the area—Photo: M. Karunakaran  

Levels of Carbon dioxide (CO2) recorded recently, caused by the burning of garbage at the Pallikaranai dump yard ranged between 515- 399 ppm (parts per million). CO2 is a major greenhouse gas.

Last Saturday, a major fire broke out at the dumping yard. Smoke from it posed both a health hazard to residents nearby and also hampered the vision of motorists in the vicinity, besides polluting the environment. Following this, the Chennai Corporation decided to suspend the dumping of garbage here.

According to data provided by the Centre for Climate Change and Adaptation Research, Anna University, global CO2 concentration levels recorded for the past month stood at only 396.78 ppm, as per the Mauna Loa observatory of the National Oceanic and Atmospheric Administration's statistics. CO2 levels recorded in areas including Sadhasivam Nagar and Ram Nagar near the Pallikaranai dump yard however, were significantly higher than this.

The team, led by the Centre's Director A. Ramachandran and consisting of R. Prasannavenkatesh, Dhanya P. and Divya S. Venu, research fellows at the Centre and G. Madesh of the Applied Geology department, Madras University, conducted a rapid assessment study for four hours each, for three days starting from June 9.

The study was carried out using portable gas analysers fitted with infrared and electrochemical sensors, which can sense pollutants rapidly.

The level of another pollutant recorded, carbon monoxide, ranged between 3 to 20 micrograms/cubic metre during the sampling hour. This is above the permitted limit of 4 micrograms/cubic metre/hour.

The level of methane that emerges mostly from solid waste dump yards and was one of the causes of the uncontrolled burning ranged between 2-5 per cent. The team also did a random survey among residents and found that a few of them suffered from breathing difficulties.

The centre is currently working on a study using a chemical transport model to see how pollutants are being dispersed through air to nearby localities. This will be done using data including hourly wind speed, wind direction, and temperature at the site. Meanwhile, the Tamil Nadu Pollution Control Board has also studied pollution levels at four locations around the dump yard.

The point atop the Centre for Wind Energy Technology in Pallikaranai recorded respirable suspended particulate matter (RSPM) levels of 216 micrograms/cubic metre. The permissible limit for RSPM is 100 micrograms/cubic metre.

Near a petrol bunk adjacent to the dump yard, the RSPM was 144 micrograms/cubic metre, at Telephone Nagar in Perungudi it was 188 micrograms/cubic metre and in Ram Nagar in Madipakkam, it was 88 micrograms/cubic metre.

According to an expert on air pollution, to predict what kind of an impact the smoke has had, an in-depth study using wind direction, temperature and relative humidity is necessary.

“CO2 levels have been measured but the impact on the atmosphere must also be studied. On days when burning happened, the skies were cloudy and a correlation between the RSPM levels and cloudy skies must be studied. It might even have an impact on local climate,” he said. Residents said the indiscriminate garbage burning was forcing many to leave the area and was also causing health problems.

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