COVID-19 Diary – Day 184

Since the early days of the pandemic, there have been several studies and hypotheses regarding the role of air pollution in the form of fine particulate matter (often called PM2.5 or PM10, as these are particles smaller than 2.5 or 10 micrometres) in the transmission and mortality level of COVID-19. One of the earlier studies done on the topic was intended to help determine why COVID-19 hit some areas much worse than others.

“Each type of particle has different material compositions and can come from different places. The smaller the particle the longer it can remain suspended in the air before settling. PM2.5 can stay in the air from hours to weeks and travel very long distances because it is smaller and lighter. PM10 can stay in the air for minutes to hours and can travel shorter distances from hundreds of yards to many miles because it is larger and heavier.” –Dylos Corp. “What is Particulate Matter”

Inhalable Particulate Matter and Health (PM2.5 and PM10) | California Air  Resources Board

We already know that PM2.5 can reduce lung function and cause respiratory illness, or lead to persistent inflammatory response even in the relatively young. For anyone with underlying respiratory conditions such as asthma, PM2.5 can be even more dangerous.

In July analysis of the spread and severity of COVID-19 in the Netherlands suggested a correlation between both the transmission and mortality of the disease with the level of air pollution in the area. What this analysis doesn’t tell us however is how air pollutants could directly lead to an increase of COVID-19 transmission.

Going back a little further, during the height of Italy’s first COVID-19 wave in April, a study was done on PM10 (particulate matter smaller than 10 micrometres) taken from air samples from Northern Italy. It was determined that air pollutants could act as a viable medium for transporting the virus and further enhance the persistence of the virus in the atmosphere.

Perhaps even more worrying is the recent news that nearly half of all the patients who survived their COVID-19 infection in Bergamo, one of Italy’s hardest-hit cities, are still suffering from the long term effects of the virus. Many people still suffer from breathing difficulties, inflammation, and blood clotting issues.


Another study on the topic of the effect of particulate matter on the transmission of COVID-19 in the city of Milan was completed in early May. This study confirmed the results of the study mentioned above and made further conclusions: “Our analysis demonstrates the strong influence of daily averaged ground levels of particulate matter concentrations, positively associated with average surface air temperature and inversely related to air relative humidity on COVID-19 cases outbreak in Milan.”

The above data graph is taken from the study of Milan, and I have edited it to include the time when Milan went into a full lockdown, as well as the end of the first incubation period after the lockdown went into effect. The data above shows a correlation between the air quality index and the number of new COVID-19 cases reported. I find it odd that the spikes in both relate so closely considering that the case report date and the date of infection could be as much as two weeks separated from each other.

Unfortunately, the effects of particulate matter on COVID-19 do not end there. As previously mentioned above, air pollution of this kind can lead to serious respiratory issues, and make COVID-19 symptoms much worse. A study completed in April by several Harvard scientists concluded that even just “an increase of only 1 μg/m3 in PM2.5 is associated with an 8% increase in the COVID-19 death rate”.

A study was also done tracking the effect of particulate matter on COVID-19 mortality in Germany, which found that increased pollution significantly affected the survival chances of people over the age of 60. The study also showed that people under the age of 60 were not seriously affected. It is worth mentioning that the pollution levels monitored for the time of this study (see graphic below) were far below that experienced in many parts of BC currently.

In conclusion, I would like to urge everyone to please take this data seriously and stay indoors as much as possible until the air advisory is lifted. I know this isn’t always possible, but every effort can make a difference.

That’s all for now, stay safe everyone!

One thought on “COVID-19 Diary – Day 184

  1. I think the close correlation between particulate levels and COVID-19 cases in Milan might be explained as follows…

    Any untested individual with mild symptoms suddenly ends up in hospital because of the added stain on their lungs.

    Any untested, infected individuals who are not showing any symptoms at first period has compromised lung capacity from the particulates when the coronavirus finishes incubating so its symptoms start off stronger.


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