Particulate matter, or PM for short, is a type of pollutant made of both liquid droplets and solid particles (hence the name, particulate). PM is one of the most common and harmful pollutants found in the air, mostly due to its tiny size.
Although PM can include particles like dust that are big enough to be seen by the naked eye, most PM particles are not that big, and that’s what makes them so scary. Their small size allows them to easily travel through to sensitive areas of your body, most commonly into deep crevices of your lungs, or sometimes even your bloodstream. This causes many respiratory and heart problems, including decreased lung function, irregular heartbeat, and aggravated asthma. Not to mention, those who are already suffering from some kind of lung or heart disease can easily have their symptoms worsened when breathing in PM-infused air.
Now, PM mostly affects the respiratory system. What else targets the respiratory system? COVID-19. Since the start of the pandemic, scientists have been hypothesizing that people with higher exposure to particulate matter face more intense covid symptoms. This makes sense: lungs that have had constant exposure to particulate matter naturally get weaker, making it a more susceptible target for a virus that attacks the lungs.
Recent studies have supported this hypothesis; for example, one done in the United State collecting data from over 3000 counties found that there was a 8% increase in COVID mortality rate with every one unit increase of PM presence.
This past March, scientists looked at it from another angle: to see if there was any correlation between elevated levels of PM pollution and the number of coronavirus cases. Previous studies had indicated that particulate matter could act as viral RNA carriers, allowing them to play a direct part in spreading COVID-19 from person to person. Therefore, the scientists hypothesized that there might be a direct relationship between them, meaning that an increase in PM in the ambient air would correlate to an increase in case counts.
Using online open-source databases, researchers analyzed COVID case counts, demographic information, and air quality data from countries all over the world. In total, they collected information about 237,749 cases from 730 regions in 63 countries across 5 continents. From the overall dataset, they found that a 10 μg/m3 increase of coarse particulates (PM10) was associated with 8.1% increase in the number of COVID cases in that area. They also found that a 10 μg/m3 increase of fine particulates (PM2.5) was associated with an 11.5% increase of COVID cases. These results supported past research analyzing data for China, Canada, and Italy. However, a similar study in Japan yielded inconclusive results, finding no direct correlation between the number of COVID cases and particulate pollution.
Overall, the data support the scientists’ hypothesis that there is a direct correlation between an increase in particulate matter and an increase in COVID cases. Although further studies need to be conducted as to why that is the case — the effectiveness of COVID being carried by particulate matter has not yet been studied extensively — these results should warn us to be aware of the danger these tiny particles pose to us. Their relationship with COVID-19 could be emulated with their relationships to other viral infections like the flu.
On a final note, it is disappointing that the vast majority of particulate matter pollution comes from power plants, industries, and automobiles. That means the emissions and the health effects that come with exposure are largely preventable. The climate and environmental justice movement is not just about protecting the earth. It’s a fight to remind each other to not hurt one another.