Welcome to another coronavirus post. Now, I know I said I wouldn’t dwell on the topic and go back to business-as-usual science based posts, but to be honest, covering other topics interests me less than it would otherwise, considering COVID-19 is impacting our daily lives in significant ways. And of course, my public health brain can’t help but find fascination in reading the emerging science about it as it comes out. Today, I thought I’d focus on coronavirus and air quality. Like with my post on coronavirus and food safety, I’m going to focus on synthesizing what we know so far; considering COVID-19 is a novel disease, we are still learning about it and trying to understand it fully.
This post will cover two topics: first, we’ll discuss what we know so far about coronavirus and air quality, and how and why the disease may be impacting air quality. Second, given that many of us are spending most of our time indoors, we’ll chat about indoor air quality in general, and what you can do to improve the air quality in your living space.
If you’d like to learn more about COVID-19, please visit the WHO website, or feel free to visit any of my posts about it thus far below:
- Food safety and coronavirus: What do we know so far?
- Some public health definitions to help you understand recent news and COVID-19
- Supplements for Immune Support: What does the science say?
- Are frozen and canned fruits and vegetables nutritious?
I plan to revisit this post once a bit more pollutant raw data is available, and am considering even running a mini analysis on my own. I am also working on a post about what increases risk of and transmission of zoonotic diseases. Stay tuned!
Are lockdowns and quarantines due to COVID-19 decreasing levels of air pollution?

News reports from around the world seem to indicate that yes, the slowdown in manufacturing and drastic decrease in transportation are decreasing levels of some pollutants.
Considering combustion emissions from vehicles are a major source of many pollutants including PM2.5 (read more about what PM 2.5 is here) and CO2, it is feasible that emission of some pollutants has decreased, given that travel has decreased and far fewer people are commuting to work or social events.
Additionally, when you consider the abrupt halt in many industrial manufacturing processes that has also occurred over the past few months, a decrease in levels of some pollutants seems feasible, as well.
However, while many media outlets have reported these decreases in air pollution across parts of Europe and in some cities in the US based on satellite data, peer-reviewed literature on the topic has been sparse.
Now, this does not mean these reports are untrue; in fact, it’s likely that they are. I just wish there was a bit more peer-reviewed literature published on the topic so I could feel more confident in synthesizing an interpretation on the matter.
I was able to find one assessment of pollution levels in China pre and post-lockdown, which found that carbon emissions dropped 25% as a result of the swift halt in industrialized activities. And a NASA report found NO2 (another pollutant) dropped 30% between January 1 – February 24, 2020.
But the NASA scientists note that this drop in pollution doesn’t necessarily mean the air quality is ‘good’ or healthy across China. Air pollution is still a major issue, even if we see what is inevitably a temporary decrease in emission levels.
A scientist at Columbia has also stated that pollution levels at her monitoring station in the city have dropped in recent weeks compared to pre-shelter-in-place levels.
Like the media reports mentioned above, these results aren’t peer-reviewed or published in any journal. In fact, I couldn’t find any peer-reviewed journal articles about air pollution levels in Europe or the United States pre and post COVID-19.
Upon some reflection, this is likely because it is a bit early to take a measurement that would span a long enough time period to be meaningful to show us what, if any, potential decreases in emissions are occuring, and if they are lasting.
Most air pollution and climate experts warn, however, that even if there is a decrease in emissions now, it is likely temporary, and not necessarily worthy of celebrations. Even if we did decrease carbon emissions by, say, 30%, the emissions levels would still be higher than they were a decade ago.
Additionally, the Trump administration issued a memorandum on March 26, 2020 that informed companies that the EPA would not be subject to fines or other legal enforcements for failing to monitor and report their levels of air, water, and soil pollution, citing the COVID-19 outbreak as the reason for the relaxation of pollution regulation enforcement.
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