Audit of air monitoring devices imminent: MPCB

Mumbai: Days after it was decided to maintain status quo on the locations of System of Air Quality Forecasting and Research’s (SAFAR) continuous ambient air quality monitoring stations (CAAQMS), the Maharashtra Pollution Control Board (MPCB) this week told Hindustan Times that an audit of these monitoring devices is imminent

Mumbai: Days after it was decided to maintain status quo on the locations of System of Air Quality Forecasting and Research’s (SAFAR) continuous ambient air quality monitoring stations (CAAQMS), the Maharashtra Pollution Control Board (MPCB) this week told Hindustan Times that an audit of these monitoring devices is imminent.

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The MPCB, SAFAR and the Brihanmumbai Municipal Corporation (BMC), on February 7, had decided to maintain a status quo on the location of these monitoring stations until further discussion.

“I have discussed this issue with the municipal commissioner, and an audit of the monitoring devices will be done to check if they conform with the Central Pollution Control Board’s (CPCB) site selection criteria. New locations for these monitors will be decided based on BMC’s land availability,” Motghare said to HT.

Municipal commissioner Iqbal Singh Chahal directed inquiries to additional commissioner (environment), Sanjeev Kumar, who did not respond to requests for a comment. A senior SAFAR official expressed surprise at the MPCB’s claim. “We have not heard back from the BMC after our meeting last week,” they said.

Motghare had earlier told HT, “The (SAFAR monitors) are placed in areas where traffic emissions are typically higher than in other places. So, this doesn’t give the correct overall picture of air pollution in the city.”

Experts, meanwhile, cautioned that relocating these monitors has no strategic merit, and will in fact set the entire SAFAR enterprise in Mumbai back by several years. They also challenged the MPCB’s claim — of all monitors being located in high-emissions areas — as being untrue.

SAFAR’s device in Chembur, for example, is located at the Tata Institute of Social Sciences, and the area comes under the ‘industrial’ classification as per guidelines of the World Meteorological Organisation (WMO). Another device in Bhandup, near the BMC’s water filtration plant, is placed in a ‘mix terrain’ location, at a topographic elevation featuring both residential settlements and background monitoring areas.

The device placed near BKC’s Nandadeep Park, meanwhile, is meant to capture pollution from urban traffic, while another in Worli is meant to assess coastal outflow and inflow of airborne pollutants.

“Moving these monitors is not a solution because you will lose their time-series data of the past few years. New devices can be placed in other locations that have different characteristics than the SAFAR monitors,” said Rakesh Kumar, former director of the National Environmental Engineering Research Institute (NEERI).

“To get efficient inputs on which actions are needed in specific areas, data needs to be analysed separately for residential areas, industrial areas, commercial areas, kerbside locations and so on,” he added.

This view was shared by Dipankar Saha, former head of the CPCB’s air quality laboratory in New Delhi, and one of the scientists who played a key role in developing the site selection criteria that SAFAR allegedly does not conform to.

“The question here is: what does the MPCB want to achieve by relocating the monitors? Are they trying to ascertain exposure of a particular population to air pollution? Are they going to place the monitors upstream or downstream of a source they are worried about?

“Are they trying to measure baseline levels for a particular geographic area, or measure the impact of a particular development on air quality at a particular location? These questions should be answered first.”

Saha said that he has not visited any of SAFAR’s monitoring locations in Mumbai. “So, I can’t tell you whether or not they have been positioned correctly. But they have been there for around eight years, and by relocating them now, the MPCB would be undoing the work put in by SAFAR’s experts over the years. The data will become almost unusable, because there’s no way to track long-term trends from those locations anymore,” he said.

Saha also pointed out that the CPCB has not issued any official guidelines for establishing multiple-monitor networks, but only for the placement of individual devices, based on what the objective of the monitor is.

For example, a monitor meant to assess traffic pollution should be placed 15 metres from the road, but an accumulative monitor should be placed 50 metres away. All monitors, however, must be placed in a well-ventilated area, should be open to the skies and have no obstruction to the flow of air in their vicinity.

“It takes a rational-minded professional with years of scientific expertise to design a well-functioning network of multiple such CAAQMS devices. If the intention of shifting a particular monitor is to simply reflect better pollution levels, then that’s poor science,” Saha added.

Sitaram Kunte, principal adviser to the Chief Minister’s Secretariat, and who served as the BMC commissioner (May 2012 – April 2015) at the time of SAFAR’s launch, said, “I would not like to comment on the monitors’ relocation, but I can confirm that the guidelines of the World Meteorological Organisation (WMO) were followed rigorously by BMC and SAFAR at the time of site selection. Eight years later, they have begun reflecting much higher pollution levels than when we launched. That’s the most concerning thing to my mind.”