Dr Gufran Beig is perhaps India’s most eminent authority on air pollution. Dr Beig was the Founder-Director of SAFAR (System of Air Quality and Weather Forecasting Research), a government-backed initiative to monitor and forecast air quality in some metropolitan cities. At the recent Explained Live event, he spoke about issues related to air pollution with the Science and Climate Change Editor at The Indian Express, Amitabh Sinha.
On whether air pollution is solvable
Whether it’s climate change, weather or geography, these factors do not produce air pollutants. They only redistribute it. We need a long-term strategy. There will be spikes in pollution even if the emissions become less, because of the large-scale air circulation.
As far as the NCR (National Capital Region) is concerned, we have employed immediate methods to deal with spikes. But a long-term solution has to be science-based. One example is an airshed approach, where we (the stakeholders, the government and policymakers) need to take collective action.
On the airshed approach in pollution management
Air pollution does not see the boundaries of a country, state or district. Air is free and so are pollutants, including CO2, that remain in the environment for hundreds of years. On the other hand, PM2.5 stays suspended for two to five days.
If we say that the airshed of Delhi extends up to, let us say, Jammu Kashmir, it is not because by the time it travels and comes to Delhi, it will die. It means that PM2.5 will be deposited by then. Therefore, under the airshed approach, we are not only focussing on the local boundary of a city. There may be local sources that are affecting the situation but beyond those boundaries, it is exploited by the weather, climatology and so on. Mapping this is a complicated issue, for which one must know climatology, weather and the domain expertise in air quality.
But it is being done and it is possible to demarcate airsheds. With this, we are taking care of not only the local sources but also covering the lifetime of those particular pollutants that are really impacting us, our health and our city. By mapping, we can see where a particular kind of pollutant will enter the city from. That is where we will see Delhi being landlocked, where it can accept everything but it can’t vomit everything.
On construction dust and its dispersal
The major problem remains with the implementation of existing guidelines. There is no need to close down redevelopment activities. Economic development, as well as health, go hand in hand with air quality. Additionally, reiterating common sense among the citizens plays a very important role. An outreach activity can help, information needs to go to the people.
For example, instead of sprinkling water everywhere indiscriminately, you need a focussed study on where one needs the dust to settle.
On stubble burning going down
We need to understand that stubble-burning counts going down doesn’t really mean much. Why? Because there is a threshold level – say 500 to 700 fire counts. Even if they are not at a number like 3,000, other conditions are still quite congenial for the overall detriment of air quality.
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There are two solutions. I am speaking here as a scientist, not as a policymaker. The feasibility of the policy will have to be seen. One is if you backwardly shift the sowing period of winter crops by around 35 days more. Then harvesting happens in September and I think we have addressed the problem very significantly.
This can happen when you can change the agricultural set-up from paddy fields to other crops. Paddy can be cultivated largely in the southern part of India where this kind of climatological problem is relatively less. I am also very optimistic about the progress on a solution to generate energy from waste, what’s called best out of waste. In four to five years, with these two combinations, this problem could be solved.
On changing the period of sowing
First, there is the air pollution aspect. We have done a sensitivity study and made a model as well. What happens if sowing is done in September instead of October-November and if stubble is burnt around the same time? We see that extreme pollution events vanish over Delhi and the Indo-Gangetic belt regions. That paper has been published.
While I am not an agricultural scientist, sowing did happen earlier – in and around 2005. As I understand, it is because of the fear that paddy requires a lot of water. If natural water from the ground continues to be used, the water table will go down and then there might be a problem in Punjab, Haryana and associated regions in terms of a drinking water shortage.
However, based on my discussions with a few hydrologists, they say that since the water table is not going up, they do not see a very significant visible impact on the water table.
On efficacy of odd-even schemes and cloud-seeding experiments
The odd-even scheme refers to cars. If you see the contribution to air pollution from the transport sector, it is something like 8 to 10 per cent from cars, out of the 41 per cent from the transport sector overall. So you are targetting that 8 to 10 per cent with absolute strict implementation.
Explained | Odd-even scheme back in Delhi: Has it helped bring down air pollution in the past?
Now there are a lot of exemptions as well, for instance, two-wheelers are not included. By discounting those, you are ultimately targetting only two to three per cent of the pollution. The question is whether this is worth the effort. A common man will face the brunt of it. I agree that the cost-benefit math probably does not match.
As for artificial seeding, it is still a very interesting and unexplored area. But there is one thing which is important for seeding a cloud: you should have a cloud. Since there was a prediction of rainfall around New Delhi on October 20 and 21, there were going to be Westerly disturbances. But what if that prediction did not hold?
Explained | Delhi govt plans ‘cloud seeding’ to induce rains amid pollution: What is this process?
Second, all the clouds are not seedable. It all comes down to cloud microphysics. There are scientists from the India Meteorological Department (IMD) who are working on these aspects. Something called CCN (Cloud Condensation Nuclei) should be there for seeding. It is in a vapourised form, you convert it into the liquid form. But again, clouds are moving. Where you are seeding, where it is raining, is again anybody’s guess. Normally, cloud seeding is done to induce rain for irrigation purposes. That is done just before the monsoon.
On working of air purifiers
Here is the principle behind air purifiers – most of them emit negative ions. They attract the smaller particles of the opposite sign and neutralise them. Now air purifiers are available from Rs 10,000 to 15,000 to about a few lakhs. All of them have an upper capacity. This is because there is a limit for producing negative ions from the source. It can only neutralise them up to a level. Beyond this, it will not work.
That is the reason that by October and November in Delhi, most of the air purifiers fail. Because even if the PM2.5 concentration is 400 micrograms per meter cube, and that gets reduced by 100, you get into the 300 microgram per meter cube range, which is still in the severe category. It helps but a purifier depends on the capacity of the source. It is the same principle why water coolers fail during summer.
Audience Questions
On benefits of artificial rain
If artificial rain is successful, it would be because it results in a significant amount of rain. If there is only drizzling, then a secondary aerosol formation starts when the temperature is cooler. Instead of improving air quality, it will ‘deprove’, because PM2.5 particles will start multiplying. Heavy rain will wash away the particulate pollutants.
On widespread use of solar energy
Solar energy is being used in many areas. If you want to drive vehicles, and replace fossil fuel with it, it is not possible. Because when there is a peak, heavy energy demand, solar cannot replace that.
On citizen action
Creating awareness in a very positive way, and not panicking is important. Try to explain the issues to the people, so that they get self-motivated to take self-mitigation measures. You can try and be vocal about the people who are visibly violating norms. Finally, limit your use of vehicles. Even if you are to use them, at least switch off whenever you can. Do not drive on the unpaved area of the road because it adds to dust.
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