Air Pollution: Understanding The Toxic Air We Breathe

Air pollution is the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. It is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mould spores, volcanoes, and wildfires. The solid and liquid particles suspended in the air are called aerosols. NASA uses satellites to monitor these aerosols and their impact on the environment and human health.

Natural sources of air pollution, e.g., wildfires, dust storms, and volcanic eruptions

Air pollution is the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. While human activity is a major contributor to air pollution, natural sources such as wildfires, dust storms, and volcanic eruptions also play a significant role.

Wildfires, often started by lightning strikes or human activity, release smoke and particulate matter into the atmosphere. These particles can include toxic chemicals such as carbon monoxide, volatile organic compounds, and hazardous pollutants that have serious health effects. Wildfires can burn large areas of land, leading to significant air pollution that can spread over vast distances.

Dust storms are another natural source of air pollution. These storms pick up and carry large amounts of dust and sand, which are then suspended in the air. Dust storms are particularly common in arid and semi-arid regions, where strong winds can lift fine particles from the earth's surface. The airborne dust can reduce visibility and cause respiratory issues, especially for individuals with pre-existing health conditions.

Volcanic eruptions can also contribute significantly to air pollution. Volcanoes emit ash, gases, and particulate matter during eruptions, which can reach the upper atmosphere and spread across vast distances. The release of toxic gases, such as sulfur dioxide, and fine ash particles can have immediate and long-term impacts on air quality. Volcanic emissions have been linked to respiratory issues and climate change, with the potential to affect global temperatures and weather patterns.

While natural sources of air pollution are significant, they do not usually create ongoing pollution problems compared to human-generated sources. However, these natural occurrences can have severe short-term impacts on air quality and public health, especially when they occur in close proximity to populated areas.

Health effects of air pollution, e.g., respiratory issues, heart disease, and cancer

Air pollution is the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. It can cause a plethora of health issues, including respiratory issues, heart disease, and cancer.

Respiratory Issues

Particle pollution exposure is linked to a variety of respiratory health effects. These include respiratory symptoms such as coughing, phlegm, and wheezing. It can also cause acute, reversible decrements in pulmonary function, inflammation of the airways and lungs, bronchial hyperreactivity, acute phase reactions, respiratory infections, respiratory emergency department visits, respiratory hospitalizations, decreased lung function growth in children, chronic loss of pulmonary function in adults, asthma development, and premature mortality in people with chronic lung disease. Older adults are more susceptible to these issues due to a higher prevalence of pre-existing respiratory and cardiovascular disease, as well as the gradual decline in physiological defenses that occur with age. Children, people with diabetes, and people of lower socioeconomic status are also at greater risk of particle pollution-related respiratory issues.

Heart Disease

Air pollution can lead to a higher risk of heart attack, irregular heartbeat (arrhythmia), heart failure, and stroke. Fine particulate matter can increase the risk of cardiovascular events, especially for those with pre-existing heart conditions. People who live near busy streets or factories are at greater risk. Even short-term exposure can be harmful.

Cancer

Exposure to air pollution can lead to lung cancer, with air pollution causing up to 29% of all lung cancer deaths. The actions taken to reduce air pollution, such as increased green spaces and cleaner energy sources, can also lead to a range of health benefits that may reduce the likelihood of developing other cancers.

Air pollution from vehicles

Air pollution is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mould spores, volcanoes and wildfires. The solid and liquid particles suspended in our air are called aerosols.

Vehicles are a major source of air pollution. The major cause of vehicle pollution is the rapid increase in the number of vehicles. In 2020, the global vehicle population was about 1.4 billion. The combustion of fossil fuels by vehicles emits a large amount of sulphur dioxide, especially from diesel fuel. Sulphur dioxide can react in the atmosphere to form fine particles, which pose the largest health risk to young children and asthmatics.

Another major pollutant emitted by vehicles is carbon monoxide, a poisonous gas formed by the combustion of fossil fuels. When inhaled, carbon monoxide blocks oxygen from the brain, heart, and other vital organs. Carbon monoxide is also a greenhouse gas, contributing to global warming and climate change.

Vehicle exhaust also emits particulate matter, which includes soot and ultrafine particles. These particles are less than one-tenth the diameter of a human hair and can penetrate deep into the lungs. They can also be formed from chemical reactions with other pollutants in the atmosphere. Exposure to particulate matter is inequitable, with Asian Americans and Black people experiencing higher concentrations than the average person in the US.

Volatile Organic Compounds (VOCs) are also emitted from vehicles and can form ground-level ozone in the presence of sunlight, a main ingredient in smog. VOCs are linked to respiratory issues and an increased risk of cancer.

Air pollution from industrial processes, e.g., burning fossil fuels

Air pollution is the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. Industrial processes, such as burning fossil fuels, are a major source of air pollution.

The combustion of fossil fuels releases a large amount of sulphur dioxide and carbon monoxide, which are major pollutants of public health concern. Fossil fuels include coal, gasoline, and diesel, which produce significant quantities of fine particulate matter, or PM 2.5, including soot. Exposure to PM 2.5 from burning fossil fuels was responsible for about 8.7 million deaths globally in 2018, according to a peer-reviewed study published in Environmental Research. This is more than twice the previous estimate of 4.2 million annual deaths from a 2015 study by the Global Burden of Disease.

In addition to the health impacts, air pollution from burning fossil fuels contributes to global warming and the depletion of the ozone layer. The ozone layer is important for preventing harmful ultraviolet rays from reaching the Earth's surface, which can cause skin diseases and eye problems. The combustion of fossil fuels also results in the formation of acid rain, which is atmospheric precipitation in the form of rain, snow, fog, or frost that contains high quantities of carbon dioxide.

To reduce air pollution from industrial processes, collective and individual contributions are necessary. This includes the implementation of technologies such as CO2 sequestering, industrial energy efficiency, and improving combustion processes. Policies that support sustainable land use, cleaner energy, and transport, as well as better waste management, can also help reduce air pollution from industrial sources.

Monitoring and measuring air pollution, e.g., using satellites and drones to track pollutants

Air pollution is the contamination of the indoor or outdoor environment by any chemical, physical, or biological agent that modifies the natural characteristics of the atmosphere. It can be caused by household combustion devices, motor vehicles, industrial facilities, and forest fires, among other sources. The effects of air pollution are detrimental, causing respiratory and other diseases and contributing to morbidity and mortality.

To effectively address this pressing issue, monitoring and measuring air pollution are crucial. Satellites and drones are increasingly being utilized to track pollutants and enhance our understanding of air quality.

Satellite remote sensing has emerged as a powerful tool for monitoring air pollution, providing data on criteria air pollutants such as PM2.5 and NO2, and greenhouse gases like CH4 and CO2. Satellites fill in the spatial gaps of ground monitoring, offering valuable information in areas without ground monitors. For example, NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depth (AOD) data has been used to estimate ambient PM2.5 concentrations, enhancing our understanding of its spatial distribution.

The use of drones in air quality testing is a relatively new development. The US Environmental Protection Agency (EPA), in collaboration with various partners, has been utilizing drones to collect real-time data on air quality, emissions, and meteorological parameters. The Alaska Kolibri experiment, for instance, involved flying a drone with a Kolibri sensor over a controlled oil fire to measure emission concentrations. Drones provide unique, high-resolution information about the vertical and horizontal structure of the dispersing plume, improving the accuracy of dispersion models.

By leveraging the capabilities of satellites and drones, researchers can better monitor and measure air pollution, identify hotspots, study health effects, and develop strategies to mitigate the impacts of air pollution on human health and the environment. These technologies disrupt the traditional paradigm of ground-based monitoring, expanding our capabilities for understanding and addressing this global challenge.

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