Improved air quality: Lessons from the COVID-19 lockdown
India—home to nine out of the world’s top 10 polluted cities—is witnessing clear blue skies after decades.
No, this is not because of effective policy design and strong implementation but due to the dramatic decrease in human activity caused by the COVID-19 lockdown. Data from satellites over northern India have revealed the lowest aerosol levels in the last two decades. Clear nights in the region and the visibility of the Himalayas from far-off places like Punjab that evoke nostalgia are unintended improvements in air quality that have brought a temporary sigh of relief to people living in high-pollution zones.
Is the air still clean?
Amid the COVID-19 lockdown, air pollution levels in Northern India including Delhi have also reduced drastically, but statistics reveal that air pollution levels are still not within the range of what the Air Quality Index (AQI) considers “good” (Figure 1). This indicates that an episode as big as a complete lockdown is also not sufficient to bring the air quality within that range. Moreover, this also highlights the damage being done through anthropogenic activities and the scale of effort that will be required if air quality has to be brought within these limits under business as usual scenario.
Despite the observed improvement during the COVID-19 lockdown, the present air quality levels put a question mark on the source apportionment studies and City Action plans drawn up for all non-attainment cities across India.
So, with minimal vehicular traffic, closed industries, vacant construction sites, and stranded roads, why is the air still not clean? Setting aside the dust storm from neighboring states for a couple of days and bursting of crackers during light-a-lamp event on April 5, 2020, the prime reason for high pollution levels is secondary pollutants. Secondary pollutants, such as ground-level ozone, are pollutants that are not directly emitted by any source but are formed when primary pollutants interact in the atmosphere.
After particulate matter (PM2.5 and PM10), ozone poses the greatest health risk to humans. Ozone formation occurs when nitrogen oxides (NOx) react with volatile organic compounds in the presence of sunlight. Nitrogen oxide (NO), which is generated from vehicular exhaust, consumes ozone—but with reduced vehicle movement during lockdown, a lower amount of NO is present. Hence, the ozone concentration has increased. The figure below (Figure 2) points to an inverse relation between NO and Ozone. Additionally, ozone formation also increases with the increase in temperature and during heat waves.
With COVID-19 already causing respiratory and lung problems, high ozone levels can further deteriorate health conditions—even though the air quality may seem good. Therefore, besides primary pollutants, a focus on reducing secondary pollutants is essential.
Learning from the lockdown
One of the key takeaways, or rather questions, from the COVID-19 lockdown is whether present AQI level should become a new baseline reference and a target to achieve once pre-COVID-19 conditions are restored.
The current situation also provides an opportunity to capture baseline data for various environmental metrics which policy makers can utilize to build sustainable models. The closure of industrial and commercial establishments and shutdown of traffic seen during lockdown, can perhaps also be used at times of extreme air quality situations – partial lockdown in stages could be incorporated in the emergency Graded Response Action Plan (GRAP) of Delhi. GRAP is a kind of emergency action plan which comes into action when AQI is severe/poor/moderate for a certain duration.
Another stark lesson from this lockdown is the cost of clean air, which unfortunately in this case is a steep economic slowdown and thousands of lives. This is of course too high a cost to pay and therefore not a solution to achieve clean air. The solution has to be found in a manner that is sustainable and achievable. These solutions will require a huge behavioral shift, with a focus on sustainable means such as the use of public transportation, cleaner fuels, abiding by regulations, and reduced stubble burning. The COVID-19 pandemic is also an opportunity to evaluate which aspects of our lifestyle are absolutely essential—and what positive outcomes are possible if we change our habits.
The key takeaways
The key takeaways from the COVID-19 lockdown on improving air quality are:
- The air quality during lockdown should perhaps become the baseline air quality and we should re-calibrate our models and targets.
- We need a strategy for reducing secondary pollutants such as ground-level ozone.
- This lockdown is an opportunity to capture baseline environmental parameters.
- A mass behavioral shift is needed to make significant impact.
- Lockdown models can be an action point for GRAP.
- Air quality improvements during lockdown indicate the scale of effort required to bring air quality within the limits.
The COVID-19 lockdown will eventually open up, but not before setting an example that it is possible to address air pollution and climate change issues. The only requirements are strong political will and social interventions. In many ways, improved air quality is perhaps the only silver lining we can take away from this otherwise grim situation. The real question is whether will we remember the clean air, the chirping birds, the Himalayan views once the lockdown is over and strive to achieve a clean sustainable living afterwards? Or will we all go back to our daily ways and lament the lack of government action – the choice is in our own hands (as always).
