The Correlation Between Exposure to Air Pollution and Covid-19

Background:

Air pollution has been an increasing problem within the last century and continues to negatively affect the environment and human health every day. This increase in air pollution is caused by the uprising of energy use and production, especially from the combustion of fossil fuels via power plants and vehicle emissions. This causes harmful chemicals to be released into the air which can have detrimental effects on human health. Poor air quality and increased air pollutants can increase the effects of asthma, lung cancer, respiratory infections, cardiovascular complications, and COPD (Kurt et al., 2016). These pollutants are especially dangerous for those that are already susceptible like children, the elderly, and those with underlying health problems.

There are several pollutants that are released within the air that affect air quality. The most common are ozone, particulate matter, carbon monoxide, nitrogen dioxide, and sulfur oxides (Ciencewicki & Jaspers, 2008). Two of the most abundant are fine particulate matter and ground-level ozone. Particulate matter is defined as small particles and droplets that are released into the air as dust, organic compounds, metals, and acid (Ciencewicki & Jaspers, 2008). Fine particulate matter (PM_2.5) is small enough and can easily be respired which can affect the respiratory system. These tiny particles are less than 2.5 micrometers which means they can penetrate deep into the alveolar sacs and reduce lung function (Xing et al., 2016). Ground-level ozone is another common air pollutant. Ground-level ozone, or smog, involves the formation of nitrogen oxides and volatile organic compounds that is dangerous for lung health (Fiore et al., 1998). There have been chamber experiments conducted which have shown that, “brief ambient-level exposures cause acute reversible drops in lung volumes, increases in nonspecific bronchial responsiveness and pulmonary inflammation” (Kinney, 1999).

Certain states within America are affected worse by air pollution due to a higher number of factories and power plants, which release more chemicals into the air. Indiana is among one of these states to house many coal-powered factories and industrial plants. As of 2018, Indiana was the second largest coal consumer and coal contributed to 59% of the total net energy (U.S. Energy Information Administration, 2020). These power plants are the major source to the distribution of pollutants into the air that contribute to Indiana’s poor air quality.

According to the U.S. news state rankings, Indiana is considered to have the second worst pollution levels out of all states and is ranked #36 for air quality (U.S. News, 2019). The reason Indiana has such horrible air quality is due to it being home to many coal-fired power plants, especially in the southern parts of the state. Southwest Indiana has numerous coal-fired power plants due to it being close to the Illinois basin which is one of the largest coal basins in the United States (Tucker, 2020). Figure 1 depicts one of the many power plants in Southern Indiana that I captured on my way down to Kentucky. This power plant is called the Petersburg Generating Station and you can clearly see the smokestack emissions. This is one of many factories in Indiana that are contributing to the addition of fossil fuels into the air.

Polluted air can cause an array of health problems, specifically respiratory problems. The Covid-19 pandemic has surfaced multiple questions as to whether there is a direct link between positive cases and/or more deaths in areas with high air pollution and poor air quality. Covid-19 is a respiratory virus that affects breathing and lung function. Since this virus is so new, multiple studies are being conducted to understand what factors worsen this illness. One study conducted in England, evaluated the relationship between Covid-19 cases and air pollution from fossil fuels. This study revealed that, “high levels of air pollutants from fossil fuels, like nitrogen dioxide and sulfur oxide, are associated with increased numbers of Covid-19 deaths all throughout England” (Travaglio et al., 2020). Another study was conducted from the Harvard T.H. Chan School of Public Health that linked Covid-19 mortality rates with long-time exposure to air pollution. This study revealed that, “someone who lived for decades in an area with high levels of fine particulate pollution is 8% more likely to die from Covid-19 than someone who lives in an area with one unit less of such pollution” (Friedman, 2020). It is presumed that people that live in areas where air pollution is high are more vulnerable to develop this disease and have a higher chance of dying from it.

Methods:

For this project, I wanted to see if there was a correlation between exposure to air pollution and Covid-19 cases and deaths. I decided to focus on four different cities within the United States which include: Bloomington, IN located in Monroe County; Davis, CA located in Yolo County; St. George Utah located in Washington County; and Wilmington, NC located in New Hanover County. I choose these cities because they all have a similar population with varying air quality levels. Bloomington, IN and Davis, CA will be the cities expected to have poor air quality and St. George, UT and Wilmington, NC will be the cities expected to have good air quality. I choose Davis, CA alongside Bloomington, IN because in 2019, it was determined that out of the ten worst polluted cities in the nation, seven of them are in California (Rice, 2019). Saint George, Utah is among the top 25 cleanest cities for the year-round particle pollution and tied for first for the cleanest metropolitan area in the country for 24-hour particle pollution and Wilmington, North Carolina was rated one of the top four cleanest cities in the U.S. (American Lung Association, 2019). I included each of the four cities populations as well as the counties populations since I collected Covid-19 data based on county numbers.

• Bloomington, IN (Monroe County)
  • City population: ~ 85,000
  • County population: ~ 150,000
• Davis, CA (Yolo County)
  • City population: ~ 70,000
  • County population: ~ 220,000
• St. George, UT (Washington County)
  • City population: ~87,000
  • County population: ~178,000
• Wilmington, NC (New Hanover County)
  • City population: ~120,000
  • County population: ~ 230,000

I used the AirNow website to record the levels of PM_2.5 and ground-level ozone for each of these four cities. The levels of fine particulate matter and ozone are measured using the Air Quality Index. The Air Quality Index is a scale that ranges from 0-500 with 0 being the best air quality and 500 being the most hazardous, as depicted in figure 2. Monitors in each city measure the major pollutants which are then converted into an AQI score based on calculations by the Environmental Protection Agency (Environmental Protection Agency, 2014).

 

Results:

I collected data for a three-week period from November 17^th to December 7^th and recorded the air quality score each day for fine particulate matter and ground level ozone in each of the four cities. Figure 3 represents the fine particulate matter levels during this three-week period. From the graph we see that Davis, California typically had the highest PM_2.5 levels whereas St. George, Utah and Wilmington, North Carolina had the lowest. Figure 4 shows ground-level ozone levels for every city besides Wilmington, NC because they don’t monitor their ozone. Surprisingly we see St. George, Utah having the highest levels and Bloomington, Indiana having the lowest. One thing to note is that overall, I expected the levels for particulate matter and ground-level ozone to be higher. One reason they could be lower during the time that I collected data could be because of the Covid-19 pandemic since there has been an overall trend of reduced air pollution rates due to not as much human activity.

 

Based on this data, Yolo County where Davis, California is located, had the lowest number of Covid-19 cases and Washington County where St. George, Utah is located, had the highest number of Covid-19 cases as of December 7^th, 2020. The number of deaths is the opposite. Yolo County has had the most deaths whereas Washington County has had the least deaths as of December 7^th, 2020. I then calculated death rate for each of the counties by dividing the number of deaths by the number of total cases. Yolo County had the highest death rate of 1.53% and Washington County had the lowest death rate of 0.75%. Although Washington County had the highest number of positive Covid-19 cases, they had the lowest death rate and Yolo County had the lowest number of cases but the highest death rate.

Discussion:

These findings suggest that exposure to air pollution correlates with Covid-19 deaths more so than overall cases. The areas that I researched with the worst air pollution (Monroe and Yolo County) also are the areas with the highest death rates for Covid-19. One possible reasoning for this could be; since long term exposure to air pollutants could harm an individual’s respiratory system, this could make them more susceptible to dying from Covid-19. There is no evidence that directly links air pollution as the sole factor for contributing to an increase in deaths, but there is evidence that links air pollution with other respiratory illnesses which could play a role in an individual developing Covid-19 and dying from it. According to the CDC, individuals that have COPD or lung cancer are at an increased risk for developing a severe case of Covid-19 (Center for Disease Control, 2020). This would also mean that those individuals have a higher chance of dying from Covid-19. Several studies have been conducted that support a link between air pollution and respiratory problems such as lung cancer and cardiopulmonary diseases like COPD. For example, there was a study conducted at Harvard University that tested six cities to see if there was a link between air pollution and mortality rates. According to the results from this study there was a significant positive correlation with mortality from lung cancer and cardiopulmonary disease especially with fine particulate matter (Dockery et al., 1993). In 2006 there was a follow up to this study that specifically looked at fine particulate matter. This follow up study revealed an increase in mortality that was associated with every 10 micrograms per cubic meter increase in fine particulate matter (Laden et al., 2006). This direct correlation between air pollution and these respiratory diseases is valuable information when studying Covid-19. Since individuals that have these respiratory diseases are at a higher risk for dying from Covid-19, air pollution could be a contributing factor in Covid-19 deaths. Although I found a correlation between areas with higher air pollution levels also having an increase in Covid-19 death rates, further studies are needed to find a causational relationship.

Conclusion:

Air pollution plays a crucial role in the development of many human health problems like respiratory illnesses including asthma, lung cancer and COPD. The air we breathe daily contains several harmful pollutants like ground level ozone and fine particulate matter that are contributing to these health problems. The burning of fossil fuels and vehicle emissions are just a few sources for the distribution of air pollutants and certain areas of the country are affected worse due to a greater abundance of these sources. Covid-19 is a newly emerging virus that severely attacks the respiratory system. This study showed a positive correlation between areas that have higher air pollution levels and Covid-19 death rates. Since this virus is so new, more studies need to be conducted to further investigate this relationship.

Works Cited:

American Lung Association. (2019). Cleanest Cities. State of the Air. https://www.stateoftheair.org/key-findings/cleanest-cities.html

Center for Disease Control and Prevention. (2020, December 1). Certain Medical Conditions and Risk for Severe COVID-19 Illness. National Center for Immunization and Respiratory Diseases. https://www.cdc.gov/coronavirus/2019-ncov/need-extra-precautions/people-with-medical-conditions.html

Ciencewicki, J., & Jaspers, I. (2007). Air Pollution and Respiratory Viral Infection. Inhalation Toxicology, 19(14), 1135-1146. DOI: 10.1080/08958370701665434

Dockery, D. W., Pope, C. A., Xu, X., Spengler, J. D., Ware, J. H., Fay, M. E., . . . Speizer, F. E. (1993). An Association between Air Pollution and Mortality in Six U.S. Cities. New England Journal of Medicine, 329(24), 1753-1759. doi:10.1056/nejm19931209329240

Environmental Protection Agency (2014). AQI Air Quality Index : a guide to air quality and                      your health. Research Triangle Park, North Carolina: United States Environmental Protection Agency, Office of Air Quality Planning and Standards, Outreach and Information Division.

Fiore, A. M., Jacob, D. J., Logan, J. A., & Yin, J. H. (1998). Long-term trends in ground level ozone over the contiguous United States, 1980-1995. Journal of Geophysical Research: Atmospheres, 103(D1), 1471-1480. doi:10.1029/97jd03036

Friedman, L. (2020, April 07). New Research Links Air Pollution to Higher Coronavirus Death Rates. The New York Times. https://www.nytimes.com/2020/04/07/climate/air-pollution-coronavirus-covid.html

Kinney, P. (1999). The Pulmonary Effects of Outdoor Ozone and Particle Air Pollution. Seminars in Respiratory and Critical Care Medicine, 20(6), 601-607. DOI: 10.1055/s-2007-1009479

Kurt, O. K., Zhang, J., & Pinkerton, K. E. (2016). Pulmonary health effects of air pollution. Current opinion in pulmonary medicine, 22(2), 138–143. DOI: 10.1097/MCP.0000000000000248

Laden, F., Schwartz, J., Speizer, F. E., & Dockery, D. W. (2006). Reduction in Fine Particulate Air Pollution and Mortality. American Journal of Respiratory and Critical Care Medicine, 173(6), 667-672. doi:10.1164/rccm.200503-443oc

Rice, D. (2019). Bad Air Days on the Rise: The Nation’s Most Polluted City Is. USA Today. www.usatoday.com/story/news/nation/2019/04/24/air-pollution-smog-soot-worst-california/3551734002/.

The New York Times. (2020). Coronavirus in the U.S.: Latest Map and Case Count. Retrieved                December 07, 2020, from https://www.nytimes.com/interactive/2020/us/coronavirus-us-cases.html

Travaglio, M., Yu, Y., Popovic, R., Selley, L., Leal, N. S., & Martins, L. M. (2020). Links between air pollution and COVID-19 in England. MedRxiv, 1-28. doi:10.1101/2020.04.16.20067405

Tucker, K. (2020). Breath of Polluted Air: How Indiana’s air pollution policies are impacting its  citizens. Indiana Health Law Review, 17(2), 339-366.

U.S. Energy Information Administration. (2020, June 18). Indiana State Energy Profile https://www.eia.gov/state/print.php?sid=IN

U.S. News and World Report. (2019). Where Does Indiana Place in the U.S. News Best States              Rankings? https://www.usnews.com/news/best-states/indiana

Xing, Y. F., Xu, Y. H., Shi, M. H., & Lian, Y. X. (2016). The impact of PM2.5 on the human                  respiratory system. Journal of thoracic disease, 8(1), E69–E74. doi: 10.3978/j.issn.2072-1439.2016.01.19