COVID-19, Air Pollution, & Wuhan, China.
Air pollution can significantly exacerbate both the transmission and severity of COVID-19: Studies have shown airborne particulate matter pollution (PM 2.5 and PM 10) can act as transmission vehicles greatly extending the range of aerosol viruses in both indoor and outdoor environments. The microscopic viruses can essentially hitch a ride on airborne pollution or particulate matter and be carried to hosts at extended distances. In addition to acting as a transmission extender and accelerant, air pollution can also damage the respiratory systems of people exposed to it. Many studies have shown fossil fuel pollutants such as sulfur dioxide (SO2), nitrogen dioxide (NO2), and fine particulate matter (PM 2.5), can cause both acute and/or chronic damage to the lungs and respiratory system depending on the intensity and duration of exposure.
Globally, one of the cities with the highest level of air pollution is Wuhan, China. The maps below show the level of PM 2.5 and SO2 in the worldwide atmosphere as of August 16, 2020:
Particulate Matter 2.5 (PM 2.5)
Sulfur Dioxide (SO2)
Examining the areas with the largest amount of air pollution, it is clear there are certain “hot spots” with significantly more air pollution than others. Due to China’s rapid economic expansion, the extent to which they have relied on fossil fuels, and coal in particular, has risen dramatically. As a result, due to lax environmental controls, air pollution has routinely increased to dangerous levels across the country.
Below are the Sulfur Dioxide levels in Wuhan on 8/17/2020. Wuhan’s SO2 pollution levels exceeded 1000 mg/m2 – 10x the current levels and the highest in the world during the initial COVID-19 outbreak in Jan/Feb 2020.
As CNN reported over a year ago, in July, 2019, the smog and air quality was so bad, Wuhan residents actually participated in protests against a new garbage incineration plant:
Holding banners with slogans such as “we don’t want to be poisoned, we just need a breath of fresh air,” thousands of people took to the city’s streets over two weeks in June and July calling for the suspension of plans to build the plant.
https://www.cnn.com/2019/07/10/asia/china-wuhan-pollution-problems-intl-hnk/index.html
“We are fearful that the plant is too close to residence area,” one protester in the city of 10 million people told state media. Others expressed concern that emissions could worsen air pollution and harm residents’ health.
Now, as we note the correlation between air pollution and the transmission of airborne viruses – in conjunction with a very densely populated city, it is apparent that Wuhan, China was actually one of THE WORST PLACES IN THE WORLD FOR COVID-19 TO BREAK OUT AND SPREAD. Tragically, not only was COVID-19 transmission exacerbated, but due to years of chronic exposure to air pollutants, the Wuhan residents were especially vulnerable to respiratory illnesses. Wuhan’s COVID-19 hospitalization and mortality rates were likely the highest of anywhere in the world.
A few related studies:
*Latest from UC Davis 8/7/20: COVID-19 death rates increase due to long-term exposure to PM2.5
A small increase in long-term exposure to PM2.5 leads to a large increase in COVID-19 death rate, with the magnitude of increase 20 times that observed for PM2.5 and all-cause mortality. The study results underscore the importance of continuing to enforce existing air pollution regulations to protect human health both during and after the COVID-19 crisis. The data and code are publicly available.
- The short-term effects of air pollutants on influenza-like illness in Jinan, China
Air pollutants, especially PM2.5, PM10, CO and SO2, can increase the risk of ILI in Jinan. The government should create regulatory policies to reduce the level of air pollutants and remind people to practice preventative and control measures to decrease the incidence of ILI on pollution days.
https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-019-7607-2
2. Effects of air pollutants on the transmission and severity of respiratory viral infections
Particulate matter, sulfur dioxide, nitrogen oxides, ozone, carbon monoxide, volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) are among the outdoor air pollutants that are major factors in diseases, causing especially adverse respiratory effects in humans.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7211639/
3. Can atmospheric pollution be considered a co-factor in extremely high level of SARS-CoV-2 lethality in Northern Italy?
In conclusion, it is well known that pollution impairs the first line of defense of upper airways, namely cilia (Cao et al., 2020), thus a subject living in an area with high levels of pollutant is more prone to develop chronic respiratory conditions and suitable to any infective agent. Moreover, as we previously pointed out, a prolonged exposure to air pollution leads to a chronic inflammatory stimulus, even in young and healthy subjects.
This, in our opinion, may partly explain a higher prevalence and lethality of a novel, very contagious, viral agent such as SARS-CoV-2, among a population living in areas with a higher level of air pollution, particularly if we consider the relatively high average age of this population. Among elderly living in such a region and affected by other comorbidities, the cilia and upper airways defenses could have been weakened both by age and chronic exposure to air pollution, which, in turn, could facilitate virus invasion by allowing virus reaching lower airways. Subsequently, a dysregulated, weak immune system, triggered by chronic air pollution exposure may lead to ARDS and eventually death, particularly in case of severe respiratory and cardiovascular comorbidities.