Back to cleaner?: Covid-19, Lockdowns, and Pollution in LAC cities

As governments in Latin America and the Caribbean (LAC) countries fight COVID-19 through various forms of lock-downs, with an enormous and unequal cost on economic activity, there are side effects, such as the effect on pollution, that could be taken as opportunities to build a cleaner development path after recovery. Indeed, as people #stayathome , cities slowdown and factories scale down their operations -either because of restrictions or because they anticipate a lower demand - air quality in heavily polluted LAC cities has been improving. The control of the pandemic became a top priority and the economy entered an “induced coma”, an experiment never seen before in modern economic history.   

This #GraphForThought shows the extent of this "lock-down effect" in eight large LAC cities by comparing the median value of PM2.5 concentration recorded each day of 2020 with that recorded on the closest date in 2019, that falls on the same day of the week. PM2.5 is a type of microscopic particle of 2.5 micrometres suspended in the air which - in high concentrations (above 35 micrograms per cubic meter of air(μg/m3)) - can be dangerous for health and is widely used to measure air quality.

What we see in the figures is that after lockdowns went into effect (as denoted by the vertical line) the median concentration of PM2.5 recorded on any given day fell in most of the cities. In Bogota, a city with a population of 7.5 million people without a subway network, the difference in air quality between 2019 and 2020 reached 34 μg/m3, two weeks after the lock down was announced. This is equivalent to about half of the average median of 2020. In Cochabamba - where the local government started forbidding the circulation of individuals on March 16th - the positive effect on air quality is notable (note that before the lockdown, the levels in 2020 were a bit higher than those of 2019); in Lima, the concentration of PM 2.5 particles also decreased after the nation-wide lock-down in Peru, although a short rebound is observed around April 2nd, probably as the president announced the gender-based permission to go out, which was cancelled 8 days later. In Mexico City - one of the most densely populated and heavily polluted cities in LAC - the air quality has not improved, likely because of less strict containment measures. Quito's average median concentration after the lock-down seems to be lower although the daily peaks reach those of 2019 in some cases. In San Salvador, there is no suggestive evidence of an improvement in air quality since even before the lock-down the concentration of PM 2.5 particles was lower this year than last year. In Santiago, the air quality has improved although not to the extent observed in other cities in the region, most likely because the lock-down has been applied selectively to certain municipalities within the metropolitan area. Finally, in São Paulo, the air quality also seems to be better after the quarantine was declared by the Governor, as the concentration of PM 2.5 is currently lower than in 2019 (which is particularly revealing since 2020 pollution was higher before the lock-down).  

This is not trivial news. Quite the contrary: considering, for instance, that every year 14 thousand deaths in Mexico and 3.5 thousand deaths in Chile are associated with air pollution, air quality is quite relevant for the population in our region. Moreover, in the context of the pandemic this suggestive evidence acquires greater meaning since according to two recent studies, long-term exposure to high levels of concentration of PM 2.5 particles is associated with higher death rates from COVID-19 in the US and in Italy. This implies that the lethality of the virus in our region could be especially high given the pollution levels of several big cities.

Observed improved air quality in countries that acted fast means that countries that took measures later could also observe less pollution (for instance in Santiago where a city-wide lockdown was announced on May 13th after a surge in the number of new cases). However, it also poses the question of whether after the measures are lifted the air quality will worsen again and what we are observing now is only a short-term effect with no real long-lasting consequences, a fear compounded by the fact that some governments could be tempted to ease protections on the environment as a way to fight the economic crisis posed by the pandemic.

Stopping economic activity is too high a cost to pay for cleaner air. However, there are lessons to be learned from this unwanted experiment. Going back to a growth model that relies so much on fossil fuels --and does not consider climate action and natural capital as a driver for recovery-- would be a lost opportunity. “Back to cleaner” could become our development pathway. The current crisis has made us more conscious of the pressure economic activity and human consumption is imposing on nature. Climate action and natural capital must be at the center of an economically and socially sustainable new normal.