Air Pollution: A Complex Solid, Liquid, And Gas Issue

Air pollution is a pressing issue that affects the health of people around the world. It can take the form of gases, such as carbon monoxide, or particulate matter, which is a mixture of tiny solids or liquid droplets that includes smoke, soot, dirt, and dust floating in the air. These pollutants can have serious health impacts, including respiratory diseases, strokes, heart disease, and lung cancer. With almost all of the global population (99%) breathing air that exceeds the recommended limits, it is important to understand the state of matter of air pollution to address this issue effectively.

Particulate matter

Air pollution can be in the form of gases, such as carbon monoxide, or particulate matter. Particulate matter (PM) is a mixture of tiny solids or liquid droplets that includes smoke, soot, dirt, and dust floating in the air. PM is a common proxy indicator for air pollution, and there is strong evidence for the negative health impacts associated with exposure to this pollutant. The major components of PM are sulfates, nitrates, ammonia, sodium chloride, black carbon, mineral dust and water.

PM is produced by the combustion of fossil fuels, such as coal, gasoline, or natural gas. Sources of PM include cars and trucks, factories, power plants, incinerators, and engines. When we breathe, our nose or sinuses capture many of the particles in the air before they get to our lungs. However, smaller particles may escape these defences and move deeper into our lungs, causing health problems.

Outdoor air pollution in both cities and rural areas is causing fine PM, which results in strokes, heart diseases, lung cancer, and acute and chronic respiratory diseases. Additionally, around 2.4 billion people are exposed to dangerous levels of household air pollution, such as from open fires or simple stoves for cooking fuelled by kerosene, biomass (wood, animal dung, and crop waste), and coal. The combined effects of ambient air pollution and household air pollution are associated with 7 million premature deaths annually.

PM is monitored by organisations such as the Washington State Department of Ecology, which keeps track of two specific size ranges of small particles. Despite these efforts, WHO data show that almost all of the global population (99%) breathe air that exceeds WHO guideline limits and contains high levels of pollutants, with low- and middle-income countries suffering from the highest exposures.

Carbon monoxide

Air pollution can be a gas or particulate matter. Gaseous air pollutants include carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide. Particulate matter is a mixture of tiny solids or liquid droplets that includes smoke, soot, dirt, and dust floating in the air.

CO is also released by a variety of items in the home, such as unvented kerosene and gas space heaters, leaking chimneys and furnaces, and gas stoves. The highest levels of CO typically occur during the colder months of the year when inversion conditions (when the air pollution becomes trapped near the ground beneath a layer of warm air) are more frequent.

Breathing air with a high concentration of CO reduces the amount of oxygen that can be transported in the blood stream to critical organs like the heart and brain. Exposure to lower levels of CO is most serious for those who suffer from heart disease, and can cause chest pain, reduce the ability to exercise, or—with repeated exposures—may contribute to other cardiovascular effects.

Ozone

Air pollution can be in the form of gases, such as carbon monoxide, or particulate matter, which is a mixture of tiny solids or liquid droplets.

The health effects of ozone are primarily related to its impact on the respiratory system. When inhaled, ozone can irritate the airways and lungs, leading to coughing, throat irritation, and chest pain. It can also worsen pre-existing respiratory conditions, such as asthma, and increase the risk of respiratory infections. Prolonged exposure to high levels of ozone can cause more severe health issues, including reduced lung function, inflammation of the lungs, and even permanent lung damage.

Nitrogen dioxide

Air pollution can be in the form of gases, such as carbon monoxide, or particulate matter, such as smoke, soot, dirt, and dust.

Sulfur dioxide

Sources of sulfur dioxide emissions include power plants, metals processing and smelting facilities, and vehicles. Diesel vehicles and equipment were a major source of sulfur dioxide, but federal regulations to reduce the sulfur in diesel fuels have significantly lowered emissions.

Frequently asked questions