MPCB decides to ‘put off’ SAFAR monitors from CPCB portal till they are recalibrated or relocated

Mumbai: The Maharashtra Pollution Control Board (MPCB), the state’s principal pollution control body, has decided to put off nine city-based SAFAR (System of Air Quality Forecasting and Research) air quality monitoring stations from its parent Central Pollution Control Board (CPCB) portal till the machines are recalibrated and/or relocated.

MPCB has communicated this decision to CPCB and submitted a report on inaccurate Air Quality Index (AQI) readings by SAFAR monitors. The monitors are managed by the Indian Institute of Tropical Meteorology (IITM), Pune, an autonomous institute of the Ministry of Earth Sciences.

Officials said around 10 days ago, MPCB had written to CPCB asking them to ‘put off’ these monitors from the CPCB portal because they were not calibrated correctly and some were not positioned as per CPCB guidelines. In response, CPCB asked MPCB for a report containing proof of such inaccurate readings, which was submitted on Thursday.

“We conducted tests at all the nine locations where IITM monitors are located and found inaccuracies in the readings, which was creating confusion and panic among citizens,” said Dr Avinash Dhakne, member secretary, MPCB.

He noted that the monitoring stations will be added back to the portal once the recalibration and repositioning work is completed.

While SAFAR data on CPCB portal is likely to be put off soon, the SAFAR app will continue to function and display the data independently. Dhakne said this data was not under the MPCB’s purview, hence he won’t comment on it.

Currently, as per MPCB, there are 23 active CAAQMS (Continuous Ambient Air Quality Monitoring Stations) monitors functioning in the city – 14 of these are by MPCB and 9 by IITM.

As on Friday evening 4pm, the average 24-hour AQI of Mumbai as per CPCB stood at 139 (moderate). The AQI bulletin from CPCB was based on 13 out of 25 monitors. (10 MPCB and 3 IITM). Six of the nine SAFAR monitors did not show the air quality data on CPCB website.

The SAFAR app, on the other hand, displayed an overall AQI of 125 on Friday evening.

A senior official with IITM, who has been closely involved with SAFAR’s operations, said, “These stations have been in operation since 2015. MPCB did not have a problem with it until last year when the city’s air quality turned poor and very poor. These are the exact same machines as used by MPCB, so how they can give incorrect readings?”

On the question of calibration, the official said SAFAR monitors are calibrated every day. “There is one calibration called ‘span’ that is done every day. Then there is routine calibration, which is done weekly or monthly based on the guidelines. So, there is no question of SAFAR monitors not being calibrated,” added the official.

“The location of SAFAR stations in each city including Mumbai is based on scientific guidelines and as per the World Meteorological Organisation (WMO). The stations are distributed in different microenvironments of a city – viz, upwind and downtown areas, background area, industrialised area, residential area, and coastal area. This way, the whole city is covered, and the average is representative,” said the official.

On February 15, HT reported that MPCB had sought to relocate nine stations run by the SAFAR on the ground that they do not accurately reflect Mumbai’s ambient air quality.