With Tamil Nadu all set to celebrate Bhogi festival, the focus has returned on the poor air quality monitoring systems in the state. While the crippling haze in Delhi has brought national attention on the crisis, experts here believe that air pollution in Chennai and other cities could be much bigger than projected, but often undermined by the lack of real-time data from the ground. 

“Our research in Ennore showed that PM 2.5 levels were high, which will have an impact on public health. But the data — real-time or otherwise — is not readily available to the public. The data is no good if it isn’t disseminated,” said Swetha Narayan, coordinator, Healthy Energy Initiative India, who has been sampling air quality in the severely polluted industrial belt in Ennore. 

There are only eight real-time air quality monitoring stations in Chennai and its periphery – three set up by the Central Pollution Control Board (CPCB) at Alandur, IIT Madras and Manali, and five by the Tamil Nadu Pollution Control Board (TNPCB) at Koyambedu, Royapuram, Perungudi (Sai Nagar), Kodungaiyur and one station at SIPCOT Gummidipoondi, besides a mobile station. 

These stations monitor particulate matter (PM1o and PM2.5), sulphur dioxide (SO2) and Nitrogen Dioxide (NO2) in addition to Ammonia (NH3), Ozone (O3), Carbon monoxide (CO) and benzene, toluene, ethylbenzene, xylene (BTEX), among others. In addition, there are eight manual ambient air quality monitoring stations that use respiratory dust sampler (RDS). 

During Bhogi, 15 additional monitoring stations are set up in the city. However, while real time stations can ensure up-to-date data, the widely-used manual method requires a day’s time to prepare the results, rendering the data outdated. According to officials, the plan to set up 25 real-time monitoring stations has been slowed down by the expense involved. 

“A manual station can be set up within Rs 10 lakh. But each real-time monitoring station requires Rs 2 crore including the cost of equipment, and operation and maintenance,” said an official from TNPCB. 

Apart from Delhi, which has the highest number of real-time monitoring stations in the country, the air quality monitoring across cities is limited, presenting an unclear picture of the threat it poses. 

According to Centre for Science and Environment (CSE), a public interest research and advocacy organisation based in New Delhi, only 303 cities out of 6,166 Census cities and towns are monitored, an abysmal 5 per cent coverage. 

Only 57 cities have continuous real time monitoring stations. The monitoring mechanism is expanding, noted Anumita Roy Chowdhury, Executive Director, Research and Advocacy, CSE, but added that it still is insufficient. 

“By monitoring only 5 per cent of the country, we are not able to profile pollution. Most monitoring is done manually, requiring a high level of quality control, and our comparison shows that manual monitors underestimate pollution. Also, the delay in accessing data on air quality makes it irrelevant. One cannot take day-to-day decisions based on this data. We need to expand real-time monitoring in big cities with high populations to make it relevant,” she pointed out.

CPCB’s data communication protocol requires data transfer from the real time monitoring stations of the state pollution control boards at a frequency of 15 minutes to estimate the Air Quality Index (AQI) for the monitoring location, which is displayed on the CPCB portal. The Index classifies air quality based on severity of pollution. However, CSE’s analysis of reporting from 50 cities for November 2017 showed that AQI values were not published daily for 22 cities. Chennai had not reported AQI for 13 per cent of the days.

The data from real-time monitoring stations has been crucial for both the authorities and public to take policy and precautionary measures to counter stifling air pollution. In Delhi, for instance, a Graded Response Action Plan based on AQI has been notified which calls for several measures to control pollution when it spikes. 

“In Delhi, the real-time data is continuously relayed to people, who can access it to take precautions. It has helped implement the graded response plan, a first in the country. This is a clear emergency plan on the action needed to be taken based on daily air pollution levels,” said Anumita. 

When the AQI is moderate/ poor (PM2.5 levels between 91-123 µg/m3), the measures include preventing garbage burning in landfills, regulations in brick-kilns and industries, periodic mechanised sweeping of roads, dust control regulation in construction activities and diversion of non-destined truck traffic among others. 

When it reaches very poor levels (PM2.5 levels between 121250 µg/m3), use of diesel generator sets are stopped, bus and metro services are increased, and parking fee is increased by four times to discourage vehicular usage. 

When PM2.5 levels are above 250 µg/m3, brick kilns, stone crushers and hot mix plants are closed and the Badarpur power plant is shut down and public transport intensified. Road stretches with high dust generation are identified, where mechanised cleaning and sprinkling of water are stepped up. During Severe+ or Emergency (when PM2.5 is above 300 µg/m3) situations, entry of truck traffic into Delhi is stopped and construction activities are brought to a halt. 

Oddeven scheme for private vehicles based on license plate numbers is enforced and the task force is mandated to take any decision on additional steps, including shutting of schools.  “While poor air quality triggers a host of policies and programmes by the Delhi government, the problem is not taken seriously in our cities. That must change,” added Swetha. 

The need for counter-measures gains a sense of urgency, as several studies show a clear link between air pollution and adverse health impact. An analysis by UNICEF, focussing on children under the age of one, has found that outdoor pollution can potentially put their brain development at risk. Over 12 million children in South Asia live in areas where air pollution is six times higher than international limits. A study by Lancet revealed that pollution accounts for 16 per cent of all deaths worldwide — three times more deaths than from AIDS, tuberculosis and malaria combined, and 15 times more than from all wars and other forms of violence.