Collaborative Clean Air Policy Centre

Policy Briefs

Sustaining air quality gains during the COVID crisis

Sumi Mehta, Tanushree Ganguly, Thomas Matte, and Daniel Kass

This commentary is part of a CCAPC series on Communicating air pollution-linked risks in India in light of COVID-19. CCAPC/2020/04 | September 2020 | Edited by Santosh Harish | Posted: September 1, 2020

Ambient air pollution is a major public health challenge in India, causing 0.67 million premature deaths each year [1]- nearly 7% of all deaths [2]. In addition, there is a strong, consistent global body of evidence demonstrating that long-term exposure to air pollution increases the risk of noncommunicable diseases (NCDs)—the same underlying conditions that make people more likely to experience severe illness and/or death from COVID-19. This further strengthens the case for urgent, proportionate mitigation efforts implemented in parallel with developing the knowledge base. Where knowledge gaps exist, air quality improvements in lockdown could throw light on location-specific strategies. 

With nearly 70% of the burden of disease caused by NCDs in India [1], including chronic respiratory and cardiovascular disease and diabetes, it is not surprising that  air pollution is a leading risk factor for NCDs [3], with nearly 10% of NCD deaths attributable to ambient air pollution [2].  Emerging evidence indicates that short-term exposure to high levels of air pollution can contribute to COVID-19 infection and death [4-6]. This is also not surprising, given that people with NCDs are most susceptible. There is also a strong, consistent global body of evidence demonstrating that long-term exposure to air pollution increases the risk of the NCDs—the same underlying conditions that make people more likely to experience severe illness and/or death from COVID-19.  

Short term improvements in air quality during periods of ‘lock-downs’, or heavily restricted social and economic activity, received public attention by showing what air quality in India’s National Clean Air Programme (NCAP) compliant cities could look like, resulting in renewed (though likely time-limited) enthusiasm for sustaining better air quality.  During the first phase of the lockdown, many cities were able to achieve PM2.5 reductions of 20-30%. For example, compared to April 2019, PM2.5 levels declined by approximately 30-50 % across cities in the NCR during April 2020 resulting in PM2.5 concentrations less than 60 µg/m3 (based on analysis of CPCB data). Bengaluru and Kolkata reported PM2.5 declines of 30 and 40% respectively during the first phase of the lockdown compared to the PM2.5 levels 30 days before the lockdown.  However, these changes have occurred as a result of drastic policies with substantial economic and social consequences, including lost income, school absences, disruption of commerce, etc.  Any environmental health benefits achieved should thus be considered a short-term positive externality of extreme measures taken during a public health emergency.

Importantly, improvements in air quality have been uneven, likely due to the lockdown’s differential impact on leading sources, like industries and vehicles, and differences in the relative contribution of these sources across cities.  Improvements in some cities were much higher than other cities, even within the same state. For instance, while Ghaziabad experienced 40 µg/m3 absolute reductions in PM2.5 levels during the first phase of the lockdown, Lucknow witnessed a decline of less than 20 µg/m3 during the same period.  Slowdowns of non-essential small- and medium-scale operations within industrial clusters had bigger impacts on air quality compared to areas with major industries deemed essential.  For example, PM2.5 concentrations in the industrial town of Bhiwadi, Rajasthan, declined by 50%, but concentrations in Singrauli, Madhya Pradesh, home to a large thermal power station, remained unchanged. 

Not only are these improvements likely to be reversed as restrictions are eased, but air quality may worsen as the economy restarts. Indeed, some may try to exploit this crisis by proposing temporary moratoriums or weakening in regulation and enforcement under the guise of easing economic consequences.  Over time, the COVID-19 lockdowns will likely be considered yet another set of ‘natural-experiments’ demonstrating the short-term benefits in air quality, followed by a rapid return to baseline levels [7].  This is not unlike the situation Beijing residents experienced when drastic measures were taken to improve air quality during the Olympics. 

What does this mean for environmental health? Ensuring sustained improvements in air quality can serve as a pragmatic pathway to improving public health by preventing NCDs overall and reducing the vulnerability to COVID-19.  In this case, however, there is an additional consideration which warrants public health concern:  increased air pollution levels will not only cause a return to previous levels of environmental health risk but may also increase the population’s susceptibility to COVID-19.  Reversals to recent improvements in air quality experienced during lockdowns are likely to cause even greater risks to public health than were present at baseline.  

While the short-lived improvements in air quality came from highly disruptive measures under the lockdown, scalable, sustainable and cost-effective approaches to reducing emissions at their source exist.  There is no need to wait - data to improve decision-making can be strengthened in parallel with the implementation process.  A recent assessment of clean air plans in 102 non-attainment Indian cities found that most plans did not include sectoral emission reduction targets, largely because of limited availability of data on the relative contribution of sources [8].  Efforts to better understand the leading sources of pollution should continue to be a priority, but sufficient information are available to inform clean air action planning.  In addition, practical guidance is available to help local governments accelerate improvements in air quality while planning for more comprehensive air quality management [9]. 

The recovery to a cleaner, more resilient future need not be one size fits all. Existing emission estimates for Indian cities [10] could be used as the basis for setting sectoral emission reduction targets. Several ‘low-hanging fruits’ to reduce key sources are well known and ready for implementation at scale.  In some cases, information on air quality before, during, and after the lockdown could be used to inform how local air quality is influenced by changes in traffic, industrial activity, and regional sources.  The reduction in pollution levels in industrial hubs like Bhiwadi clearly suggests that industries need to be monitored better to identify the units that are polluting in nature. 

Improving long-term air quality will improve public health.  Measurable benefits will be achieved through reduced illness and death, associated savings in health care expenditures and treatment costs, and reduced burden on the health system overall.  In addition, given that health systems are already stressed by the pandemic, this is an opportune time to focus on a preventive strategy where solutions lie beyond the clinical setting. 

As clean air plans are developed to promote a healthy, sustainable ‘new normal’, efforts must actively consider the populations most likely to be exposed and impacted. (This is the legacy Kirk Smith has left behind for all of us to remember as we continue our work!)  The urban poor likely to be most exposed, for example, and those with pre-existing NCDs, as well as those most susceptible to NCDs due to age, nutritional status, lifestyle, or pre-existing conditions are likely to be most impacted.  Clean air action for public health must take populations most vulnerable to air pollution and COVID-19 into account. 

Mehta, Matte and Kass are affiliated with Vital Strategies, USA. Ganguly works with the Council on Energy, Environment and Water, New Delhi.

For the rest of this series, click here.

References

  1. Balakrishnan K, Dey S, Gupta T, et al. The impact of air pollution on deaths, disease burden, and life expectancy across the states of India: the Global Burden of Disease Study 2017. Lancet Planet Health. 2019;3(1):e26-e39. doi:10.1016/S2542-5196(18)30261-4

  2. GBD Compare | IHME Viz Hub. Accessed July 9, 2020. http://vizhub.healthdata.org/gbd-compare

  3.  Landrigan PJ, Fuller R, Acosta NJR, et al. The Lancet Commission on pollution and health. Lancet Lond Engl. 2018;391(10119):462-512. doi:10.1016/S0140-6736(17)32345-0

  4. Wu X, Nethery RC, Sabath BM, Braun D, Dominici F. Exposure to air pollution and COVID-19 mortality in the United States: A nationwide cross-sectional study. MedRxiv Prepr Serv Health Sci. Published online April 7, 2020. doi:10.1101/2020.04.05.20054502

  5. Zhu Y, Xie J, Huang F, Cao L. Association between short-term exposure to air pollution and COVID-19 infection: Evidence from China. Sci Total Environ. 2020;727:138704. doi:10.1016/j.scitotenv.2020.138704

  6. Liang D, Shi L, Zhao J, et al. Urban Air Pollution May Enhance COVID-19 Case-Fatality and Mortality Rates in the United States. MedRxiv Prepr Serv Health Sci. Published online May 7, 2020. doi:10.1101/2020.05.04.20090746

  7. Burns J, Boogaard H, Polus S, et al. Interventions to reduce ambient air pollution and their effects on health: An abridged Cochrane systematic review. Environ Int. 2020;135:105400. doi:10.1016/j.envint.2019.105400

  8. Ganguly, Tanushree, Kurinji, LS, Guttikunda, S. How Robust Are Urban India’s Clean Air Plans? An Assessment of 102 Cities. Council on Energy, Environment and Water; 2020.

  9. Vital Strategies. Accelerating City Progress on Clean Air: Innovation and Action Guide. Vital Strategies Accessed July 10, 2020. https://www.vitalstrategies.org/resources/accelerating-city-progress-on-clean-air-innovation-and-action-guide/

  10. Guttikunda SK, Nishadh KA, Jawahar P. Air pollution knowledge assessments (APnA) for 20 Indian cities. Urban Clim. 2019;27:124-141. doi:10.1016/j.uclim.2018.11.005

COVID and AQSantosh Harish