By Helen Gloege ’23
Staff Writer
At the start of this year’s pandemic-induced lockdown, a decline in air pollution produced photos demonstrating a clearer, lighter and completely unobstructed view of the India Gate War Memorial in New Delhi, India, and the clear, blue waves of the Grand Canal in Venice, Italy, known for its murky waters. These examples of the real-world impact of decreased air pollution reveal the dramatic effects of what the world would look like if air quality improved. While the amount of global air pollution has a clear connection to human activity, there is little known about the impact of air pollution on human health and what possible compounding effects it might hold for future generations.
The World Health Organization estimates that over 90 percent of the world’s population breathes air containing harmful pollution levels. Polluted air often contains airborne particulate matter that is considered especially dangerous. Particulate matter refers to the mix of solid particles and liquid droplets. Some particles are large or dark enough to be seen with the naked eye, such as dust, dirt or smoke, while others are microscopic and remain unseen.
According to the Environmental Protection Agency, particles come in various sizes and shapes and can entail hundreds of different chemicals. Some particles are emitted directly from sources, such as fires, fields or construction sites. Most of the particles form in the atmosphere due to chemical reactions, such as sulfur dioxide and nitrogen oxides emitted from power plants, industries and automobiles.
There is not much known about the impact or location of particulate matter. The National Aeronautics and Space Administration is planning a satellite mission that will help determine connections between particulate matter, air pollution and human health. The Multi-Angle Imager for Aerosols satellite will launch into orbit around the Earth in 2022. The data from the satellite will provide maps of particulate matter air pollution that will be used by epidemiologists to study different types of particulate matter and its impact on health.
Currently, there is a belief that infections derived from air pollution-related health problems make people more susceptible to severe illnesses. Larger particulate matter is responsible for irritating airways, while smaller particles may go deeper into the lungs and cause inflammation that affects other organs. Particulate matter 2.5 micrometers in diameter or smaller is associated with an increased risk of respiratory and cardiovascular diseases. People who breathe more particulate matter are more likely to develop lung cancer, lower respiratory infections, chronic obstructive pulmonary disease and health issues during pregnancy.
A map produced by Physicians for Social Responsibility shows neighborhood-by-neighborhood pollution levels across Los Angeles overlaid by COVID-19 case counts. The maps show that heavily polluted areas tend to worsen COVID-19 outbreaks, while areas with less pollution have fewer COVID-19 cases. Researchers at Harvard University reported that individuals living in areas with higher smog levels were more likely to die from COVID-19. Other researchers from Emory University found a similar correlation that linked higher COVID-19 death rates with nitrogen dioxide exposure.
It is unlikely that air pollution is the full story. Redlining practices frequently exclude people of color from neighborhoods considered desirable, instead pushing them into housing near freeways, refineries and power plants. COVID-19 has disproportionately affected people of color. They are more likely to suffer from preexisting conditions, less likely to have access to health care and more likely to work jobs that are not remote. This information indicates that air pollution exposure isn’t the full story, and it is probable that there are other effects at play.
Scientists have used monitoring instruments on or in the ground to measure air pollution exposure. However, to gain an accurate sample, a dense array of monitors is needed. The Multi-Angle Imager for Aerosols satellite will acquire data from space, preventing a need for monitors on the ground. Completed studies will examine the impact of long-term exposure to air pollution, focusing on particular locations. The target areas will be based on a set of criteria, including population, variability in the amount and type of particle matter, how well monitored the area is and access to public health records. The data will also apply to other research, including investigating aerosol and cloud interactions with climate. Aside from epidemiologists and other scientists who will use the raw data, policymakers and air quality regulators would also benefit from the information.
This information will benefit a recent international health study called the Global Burden of Disease, which claimed that breathing in particulate matter resulted in over 4 million premature deaths globally. Another recent study specifically addressed the impact of air pollution on people in South Asia. It is expected that in New Delhi, going outside and simply breathing the air can shorten one’s life span by over nine years.
There is currently a surge in air pollution in India, Pakistan, Bangladesh and Nepal. Bangladesh currently leads with the lowest average life span, with air pollution cutting the average life expectancy by about 6.2 years. Air pollution will shorten the average Indian life expectancy by 5.2 years. There are certain areas with much worse average life expectancy reductions, such as Delhi’s 9.4 years and Uttar Pradesh’s 8.6 years. Meanwhile, in Pakistan, the average life is shortened by 2.7 years. In Nepal, life expectancy is cut by 4.7 years.
The traditional air quality index provides daily air quality assessments but does not include the health risks that may result from the air quality. The air quality life index converts particulate matter air pollution into its impact on life expectancy. This work has quantified the causal relationship between human exposure to air pollution and reduced life expectancy.
Particulate matter, as previously mentioned, has an impact on respiratory, immune and cardiovascular systems. Recent studies have pointed toward a link between long-term exposure to air pollution and global deaths from COVID-19. A study published in the Cardiovascular Research journal estimates that about 15 percent of global deaths from COVID-19 could be linked to particulate matter exposure. The study analyzed health and disease in the U.S. and China in connection with air pollution, including COVID-19 and SARS. The information gathered from the study was combined with data from satellites and ground monitoring on global exposure to particulate matter. That information was combined with satellite data and ground monitoring of global exposure to particulate matter. Particulate matter is known to increase the likelihood of COVID-19 risk factors such as asthma, lung and heart problems. Moreover, particulate matter appears to increase ACE-2 receptor activity, which is known to be involved in the way COVID-19 infects patients. The study says that this doesn’t mean pollution is responsible for killing people with COVID-19. Still, the pollution particles are likely factors that aggravate the disease.
Current information highlights how little we know about the effects of air pollution and particulate matter on human health. Governments are responsible for setting limits on hazardous air pollutants to protect the public. Still, it is hard to determine the line for acceptable risk without adequate information. We know that methods for monitoring and estimating air toxins aren’t sufficient enough to determine the risks to human health, and more research needs to be done on the long- and short-term impacts. Attention must be paid to the separation of causal factors, as the combinations of hazardous air pollutants could have cascading effects and cause different outcomes.
