Deployment of sensor-based air quality monitors in Meghalaya is a welcome step

Sensor-based technology — being developed for the past few decades — has leapfrogged in recent years

By Digvijay Singh Bisht
Last Updated: Thursday 02 April 2020
Shillong is Meghalaya's capital and is the most densely populated city in the state Photo: Wikimedia Commons

The adoption of a sensor-based monitoring technology for measuring particulate matter (PM10 and PM 2.5) by Meghalaya’s state pollution control board (MSPCB) is a significant acknowledgement of this technology by a regulatory agency.

The MSPCB will begin its trial phase by rolling out the technology in select cities — using low-cost monitors — before expanding its current air quality-monitoring network.

This will assess ground-level data at different areas across the state and use this information for future regulatory network planning.

Sensor-based technology — being developed for the past few decades — has leapfrogged in recent years, benefitting from extensive research and investment and data democratisation by personalising monitoring methodology.

The results of recent pilot projects make this technology promising and suitable for many monitoring objectives excluding regulatory monitoring, although issues of data quality and functioning of the technology are major bottlenecks.

The procurement of five air quality monitoring devices by MSPCB for their monitoring network highlights this technology’s relevance. It helps MSPCB expand their air quality network (especially for urban centers), identify air quality in places across the state (including hotspots) and assess impacts of industrial sources on urban air quality.

This is a proactive step by the MSPCB, considering it highlights their plans for investing towards improving their monitoring network using sound data.

The regulatory body receives a funding of Rs one crore under the National Clean Air Programme (NCAP).

This initiative has generated interest from the neighboring states of Sikkim and Tripura as well.

Byrnihat is the only non-attainment city in Meghalaya, according to an NCAP report published in January 2019 by the Ministry of Environment Forest and Climate Change (MoEFCC).

Non-attainment cities are those cities that do not meet national air quality standards.

Rapid urban and industrial development, however, pushed MSPCB to ensure no more cities are added to this list.

MSPCB plans to deploy the air quality monitoring instruments for gathering preliminary baseline data for estimating air quality on a continuous basis, since it suspects a few unmonitored areas of having poor air quality.

This can be helpful for planning the future course of action in such areas and ensuring better compliance enforcement.

Each air quality monitoring device costs around Rs 20,000, making it affordable and convenient for deployment, compared to a Continuous Ambient Air Quality Monitoring Station (CAAQMS) which entails huge capital including operation and maintenance (O&M) and skilled manpower.

The monitoring devices, however, incur O&M charges after a two-year warranty period.

Five devices are currently deployed outside the MSPCB’s main office complex in Shillong. They generate air quality data in surrounding areas. They will, however, be relocated soon to other locations, with deployment likely to happen across Shillong, Cherrapunjee, Jowai and Byrnihat.

Map depicting all five ATMOS monitors

Source – Ronak Sutaria, Respirer Living Sciences

An analysis of manual monitoring data shows compelling reasons for selecting the sensor technology for Meghalaya’s cities:

  • Shillong was selected since it is the capital and the most densely populated city in the state, followed by Jowai, which has a rapidly increasing population
  • Cherrapunjee has extensive urban and industrial development around it, making it a major hotspot
  • Byrnihat, a border city, has a major industrial area that Meghalaya shares with Assam

This is in no way a regulatory monitoring exercise and is only being undertaken to enhance the existing monitoring network.

MSPCB is simultaneously installing three CAAQMS with the help from Central Pollution Control Board (CPCB).

Two CAAQMS have been sanctioned for Shillong, with one being installed at the PCB office and the other at a sports complex and one for Tura, the second largest city in Meghalaya.

The state still falls short of adequate spatial coverage and sensor-based monitoring can fill in till funds are allocated to further enhance the regulatory network.

“After receiving the purchase order, all ATMOS instruments were shipped to MSPCB along with an instruction email for installations and activation,” said Ronak Sutaria, founder Respirer Living Sciences, the company that manufactures the devices used in Meghalaya.

Correlation between ATMOS monitors

Source: Ronak Sutaria 

“MSPCB officials were able get these instruments up and running only with this information,” he added.

The monitors show extremely high correlation with each other, he said, adding that the devices supplied by his company will be correlated with CAAQMS monitors as well.

Concentration curves (PM10 and PM2.5)

Source: Ronak Sutaria 

This will guide future research by getting answers to some important questions: The importance of instrument calibration with respect to PM concentration in a local area, the time duration of such correlation exercise and local meteorology significance in such studies.

Another challenge is the heterogeneous nature of PM in India, resulting in particle density variability, an important aspect in PM measurement.

This initiative is surely a positive step by the MSPCB, providing a focused evaluation of the sensor-technology for area-based air quality monitoring networks.

It will also highlight its suitability for activities like hotspot monitoring and per-baseline determination of air quality.

More such instruments will be deployed to cover other areas of the state, if this trial delivers on the desired results.

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