Are we better equipped to assess air quality in 2019?

The use of technology in addressing air pollution has been growing at an incredible pace, but then the scale of the problem has also grown and expanded with time

By Tanushree Ganguly
Published: Thursday 17 January 2019
Representational Image. Source: Wikimedia Commons

On January 10, 2019, as the Ministry of Environment, Forest and Climate Change was gearing up to launch the National Clean Air Program (NCAP), a group of researchers and entrepreneurs got together for the sixth edition of Social Entrepreneurs and Enterprises—an IIT Kanpur Alumni Association Initiative.

Interestingly, the theme for this year was finding implementable solutions for India’s air pollution problem. Researchers from IIT Kanpur and Delhi presented their cutting-edge findings, which have the potential to shape the future of air quality assessment protocol and inform clean air policies in India.

Technologies ranging from sensor-based monitors to air purifiers to smog towers were presented. The organisers of the event remembered Anil Agarwal as the IIT Kanpur alumnus who authored the first State of Environment Report for India.

As a representative for the Centre for Science and Environment (CSE) at the event, I took up the opportunity to assess how this vast amount of research could complement or enhance the steps that are being taken by the government to combat the problem of air pollution.

For instance, the recently launched NCAP directs the 102 non-attainment cities in the country to formulate clean air plans. While the nature of sources across the cities tends to be similar, it is the relative contribution of the sources that varies from city to city. 

In order to prioritise action and devise a time-bound action agenda, it would be imperative to assess the relative source contributions. Traditionally, source apportionment studies have been long-term experiments involving on-site sample collections using filter papers, and then off-site analysis of these collected samples using ion chromatography or exposing the collected samples to mass spectrometers.

Also, samples need to be collected on a seasonal basis to understand how the contributions of sources per season. The incredibly high particulate concentrations in Delhi during winters have irked citizens and researchers alike. 

Professor Sachchida Nand Tripathi of IIT Kanpur has been studying Delhi’s pollution for over a decade now and was kind enough to answer my questions on his on-going study, which involves assessment of Delhi’s particulate matter composition and formation using quick source apportionment methods.

This could be a game changer as it can expedite the traditional long-term source apportionment studies. The study entails deployment of mass spectrometers at representative locations that are aligned with the predominant wind direction. 

Tripathi is leading a team of researchers from IIT Kanpur, IIT Delhi, Indian Institute of Tropical Meteorology (IITM) Delhi branch, Paul Scherrer Institut and Manav Rachna International University to carry out a first of its kind study in India. Mass spectrometers have been deployed at three locations in Delhi, including the IIT Delhi campus, IITM Delhi branch and Manav Rachna University campus.

The mass spectrometer analyses secondary organic aerosols that constitute particulates in the atmosphere. The idea is to arrive at the age and chemical composition of these secondary aerosols. This information in turn helps identify the sources of these organic aerosols and the residence time of the particulates in the atmosphere. 

The operation mechanism of this versatile equipment is rather complex. It fragments a concentrated particulate beam into ions of varying masses. The atomic mass unit (AMU) of an ion corresponds to a specific source, or in other words is the source signature.

For instance an ion having an atomic mass unit between 60 to 70 could possibly be generated through biomass burning. The mass spectrometer thus generates a time series of mass spectra which then gets analysed using a source apportionment model, thereby aiding the process of source identification.

In addition to the above analysis, something called isotope fractionation is also being carried out to distinguish between polluting process that can have a similar source signature. For instance, this could help distinguish between bio-fuel and fossil fuel combustion.

The IIT Delhi campus is also operating an additional ‘electrospray ionization mass spectrometer’. This device could help identify source signatures of combustion of different kinds of oils being used in industries.

A 2017 Supreme Court order banned the use of furnace oil in Delhi-NCR. A device like this could help verify whether unauthorised and illegal use of such oil persists despite the ban.

Tripathi informs me about yet another equipment called the ‘Proton transfer mass spectrometer’ that could be used to identify sources behind volatile organic gases. These gases act as precursors for formation of secondary particulate matter in the atmosphere. Thus, apportioning these gases to their sources could also help identify possible causes of particulate pollution in a city.

Use of on-site mass spectrometers is a relatively new phenomenon. They have been in use since early 2000s. China is reportedly using hundreds of such mass spectrometers to continually assess its air quality. India has just started deploying these.

But can these be deployed at a large scale across the country? Probably not, given how expensive these instruments tend to be. The mass spectrometers that have been deployed in Delhi cost around Rs 6 crore. But, if these are produced within the country, the costs would come down significantly.

While use of advanced technologies to assess air quality is picking up in the country, forecasting air quality to predict air pollutant concentrations has also been on the radar of policy makers and advocates.

The IITM in Pune, under the Ministry of Earth Sciences (MoES), currently runs the System of Air Quality and Weather Forecasting and Research (SAFAR) to forecast air pollution trends in Delhi, Mumbai, Pune, and Ahmedabad. In October 2018, an early warning system was put in place by the MoES.

These forecasting models take emissions and meteorological parameters as inputs and generate pollutant concentrations on the basis of the same. Chemical transformations occurring in the atmosphere are also taken into account.

An emission inventory is essentially a summary of emissions from all possible sources of pollution and the results would certainly differ from that of a source apportionment study as all the emissions may not get translated into formation of particulate matter.

This discrepancy between results of an emission inventory and source apportionment has baffled policy makers in the country for a while and needs to be put to rest.

The use of technology in addressing issues related to air pollution has been growing at an incredible pace. But then the scale of the problem has also grown and expanded with time.

If experts are to be believed then the problem is here to stay, and the decline will be gradual and not instantaneous. Systemic measures, long term planning with emphasis on cleaner energy and cleaner production will be key to cleaner air in the country.

While we might be better prepared in understanding and demystifying air pollution than ever before, the preparedness has remained confined to Delhi. Cities across the Indo-Gangetic plain scream and smell of foul air as well as absolute inaction. 

With the NCAP, cities are beginning to devise their clean air agenda, but a mere paper-bound agenda cannot be the only solution. Working out a mechanism to implement and monitor the action points, cross-sectoral and inter-departmental coordination and continuous monitoring and assessment of a city’s air quality are absolutely essential to observe any discernible improvement on ground.

Cities looking at technologies like cloud seeding and smog towers as the solution to their air pollution problem need to understand that these are only interim solutions and will not eliminate the problem. Technology needs to be curative and not preventive.

Summing it all up, I would say that yes, a lot is happening, but all this might fall short given the scale of the problem. And I would like to reiterate that Delhi is not the only battleground. Take a look outside Delhi, it is pretty hazy out there!

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