We know now that viruses like SARS CoV-1 and SARS CoV-2 can survive in the air as an aerosol for several hours and can travel longer distances than previously thought. But can weather changes like increased smog or dust in the air increase the risk of catching the virus?
New evidence, although still debated, suggests that it can. Spikes in viral respiratory infections, both SARS CoV and influenza, have been observed in various locations after an event of increased fine particulate matter in the air. This includes both smog and dust storms.
The word “smog” is a combination of the words smoke and fog, and describes an environmental condition where fog is mixed with smoke, car exhaust and/or other chemical pollutants, creating a brown, grey, greenish or yellowish haze. In London, England, where this was common in the past due to burning of soft coal for home heating, they would refer to this as a “pea souper”. Coal is still used for heat in many parts of the world, in spite of the pollution it creates. Higher quality, harder “anthracite” coal is preferred, as it produces less smoke and less pollution. Wood and coal are considered approximately equally in polluting effects.
How does smog increase risk?
Researchers hypothesize that 2 things could be happening to increase risk of viral spread during smog conditions:
Increased numbers of fine particles floating in the air make it easier for virus aerosols to form, stay suspended in the air, and travel farther, causing increased risk of infection spreading.
Particles, when inhaled, irritate the lining of the lungs, creating inflammation and irritation, worsening existing chronic conditions like asthma, and making it easier for a virus to take hold.
Another weather factor that appears to contribute to increased infections, is what is called a “temperature inversion”. Normally air temperatures decrease with increased altitude – as you move farther from the surface of the earth, the temperature drops. With a temperature inversion, cooler air is trapped close to the earth’s surface with a warmer layer above it. This inversion of temperatures appears to trap not only cool air, but particles as well, creating conditions of increased smog and pollution – visible clouds of particles in the air we are breathing.
Fine particulate matter
This fine particulate matter is also referred to as “PM2.5” and some areas with frequent pollution problems track its measurements daily. Health authorities are also closely tracking cases of COVID-19, so scientists have been able to compare spikes in both in various areas around the world. Data from Tenerife (Canary Islands), London, the Swiss Canton of Ticino, and Paris supported the researchers’ hypothesis that increased particulate matter in the atmosphere and temperature inversions were followed by a spike in cases and deaths from COVID-19. Comparison charts are available in the references below.
While spread of viruses like SARS CoV-2 can occur without the environmental conditions described, it has been known for decades that peaks in fine particulate matter and smog can play a critical rose in the spreading and severity of viruses. While early cases have been identified weeks and months before the pandemic struck in several areas, it may be that smog and haze conditions were needed to enhance virus spread to dangerous levels.
This supports the idea that it may be a good idea to wear masks to protect against inhaling fine particles on days with increased smog or pollution to reduce risk of respiratory infection even when not near others and after the pandemic is controlled. Will we continue to use this tool to prevent infection in the future, at least during flu season?
I’m thinking I’ll likely be taking a few masks with me any time I travel by air, even after I’ve been vaccinated against COVID-19. I’m remembering a miserable visit my son and family had with us in Florida, where they all took turns with symptoms of an obvious viral infection, no doubt caught on the plane on their way to visit us as they were all fine before they left home.
My son said he couldn’t think of a better place to be sick, but it really spoiled what should have been a wonderful break from winter. Maybe masking on the plane (and washing hands more too!) could have prevented it all. If nothing else, we’re all learning how to reduce virus transmission through all this…
Advice for the future?
Meanwhile, if scientists continue to find more evidence to support this theory, perhaps weather advisories will help to predict worsening of risk of viral infections and provide reason for us to increase personal protections on those days, like wearing a mask as they do in Asian countries on smoggy days. But at the very least, it will provide yet another reason to reduce air pollution and work improve our environment.
I like to hear about new research into the Coronovirus – I figure, the more we learn, the better we will know how to control this terrible virus. On the news last night, the announcer said deaths from COVID-19 for the previous day were greater than the number of people who died in 911. We’re seeing 911 every day and COVID-19 has become the #1 cause of death in the US.
So, stay safe and keep others safe too, whether you know them or not. It’s going to take several months to get everyone vaccinated so we can get back to normal lives again, but we know how to protect ourselves and others until then. I know you’ve heard this many times (but I just have to say it again…): Keep your distance from others when out, wear a mask, wash your hands, stay home as much as possible. If we celebrate our holidays quietly this year, more of us will still be here for next year’s celebrations.
References:
Link between air pollution and COVID-19 spikes identified – Medical News Today
Peaks of Fine Particulate Matter May Modulate the Spreading and Virulence of COVID-19 – Springer Link
