The Air We Breathe: Pollution Sources

Air pollution is a major threat to global health and prosperity, causing over 6.5 million deaths each year. It is caused by solid and liquid particles, known as aerosols, and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes, and wildfires. Mobile sources such as cars, buses, planes, trucks, and trains, as well as stationary sources such as power plants, oil refineries, industrial facilities, and factories, are major contributors to air pollution. In addition, agricultural areas, cities, and wood-burning fireplaces also emit pollutants into the air.

Burning fossil fuels

The combustion of fossil fuels is a major source of smog and soot, which are types of air pollution. Smog, or ground-level ozone, occurs when emissions from burning fossil fuels react with sunlight. Soot is made up of tiny particles of chemicals, soil, smoke, dust, or allergens that are carried in the air. Cars, trucks, factories, power plants, and anything that burns fossil fuels contribute to smog and soot pollution.

The health impacts of air pollution from burning fossil fuels are significant. Fine particulate matter, known as PM 2.5, is of particular concern. These tiny particles can be inhaled deeply into the lungs and contribute to serious health problems, including respiratory issues, asthma, cardiac problems, and even cancer. They can also enter the bloodstream and damage multiple organs. Vulnerable populations, including children, older individuals, low-income communities, and people of color, are often disproportionately affected by the health impacts of air pollution, due to various social and environmental factors.

Additionally, the combustion of fossil fuels contributes to the global climate crisis. The increased levels of greenhouse gases in the atmosphere have already led to a global temperature rise of 1°C, with temperatures surpassing 1.5°C in 2024. This warming has resulted in extreme weather events, biodiversity loss, species extinction, food scarcity, and worsening health and poverty for millions worldwide.

To address the issue of air pollution from burning fossil fuels, a transition to renewable energy sources is imperative. While fossil fuel companies continue to produce and sell these products, it is essential to advocate for progressive climate policies and increase public awareness about the true impact of fossil fuels on our health and the environment.

Industrial processes

Refineries, mills, mines, and manufacturing plants emit dangerous airborne pollutants, including particulate matter (PM), which can have severe respiratory and cardiovascular health impacts. PM2.5, for example, is a subset of fine particulate matter that is 30 times thinner than a human hair and can be inhaled deep into the lungs, leading to serious health issues.

The natural gas, plastic, chemical, electric generation, and waste disposal industries are also responsible for generating hazardous waste. Improper disposal methods, such as waste incineration, can introduce harmful substances into the atmosphere, including toxic gases and pollutants that contribute to smog and acid rain.

Mining activities, in particular, release numerous airborne pollutants, including silica dust, coal dust, methane, carbon monoxide, sulfur dioxide, nitrogen oxides, and heavy metals such as mercury and lead. These pollutants have severe health consequences, including respiratory issues, neurological problems, and even lung diseases like silicosis and black lung disease.

Petrochemical plants, which process hydrocarbons derived from crude oil and natural gas, emit several airborne pollutants, including PM2.5, sulfur dioxide, nitrogen oxides, volatile organic compounds (VOCs), and hazardous air pollutants (HAPs).

Additionally, fracking-related infrastructure, steel-making plants, and hazardous waste sites contribute significantly to industrial air pollution, negatively impacting public health and exacerbating climate change.

To mitigate the impact of industrial processes on air quality, it is essential to focus on industrial process upgrades, energy efficiency improvements, waste management, and the adoption of applicable technologies for reducing emissions.

Transport

The health effects of mobile source air pollution are significant, affecting millions of people, especially those who live near busy roads. Pollutants from vehicle exhaust have been linked to adverse impacts on nearly every organ system in the body, with exposure disproportionately affecting Latinos, Blacks, and lower-income households. Fine particulate matter, or PM2.5, is of particular concern as it can be inhaled deeply into the lungs, contributing to serious health problems, including respiratory issues, asthma, and cardiac problems.

Tailpipe emissions from cars, trucks, and buses account for over one-fifth of the United States' total global warming pollution. Heavy-duty vehicles, which make up about 10% of all vehicles on the road, produce more than 25% of global warming emissions, 45% of NOx emissions, and nearly 60% of direct PM2.5 emissions from on-road vehicles. These emissions have economic impacts as well, with residents in polluted areas experiencing increased medical costs and missed workdays.

Freight transportation is a significant contributor to air pollution and climate change. The challenge of reducing emissions from this sector is growing as the United States moves more freight each year. However, there are efforts to address this issue, such as the SmartWay Program, which aims to improve supply chain efficiency and reduce air pollution from freight operations.

The US Environmental Protection Agency (EPA) has implemented national programs and standards to reduce air pollution from transportation sources, including the Diesel Emissions Act Reduction program, which provides funding to reduce harmful emissions from diesel engines, and the Clean School Bus Program, which aims to replace existing school buses with zero- and low-emission models. These programs have resulted in significant improvements in air quality and the health of Americans. By 2030, EPA air quality emissions standards for vehicles are projected to prevent thousands of premature deaths and reduce respiratory symptoms for millions of people.

Wildfires

Air pollution is a mix of hazardous substances from both human-made and natural sources. Mobile sources, such as cars, buses, planes, trucks, and trains, account for more than half of all air pollution in the United States. However, natural sources, such as wildfires, can also contribute significantly to air pollution.

The health effects of exposure to wildfire smoke have been well documented. Fine particulate matter from wildfire smoke has been linked to similar health effects as those attributed to fine particles from other sources, such as vehicles and industrial emissions. The association between PM2.5 and heart and lung health issues is also supported by scientific literature. Exposure to wildfire smoke can aggravate existing health problems and increase the risk of heart attack, stroke, and other cardiovascular and respiratory outcomes.

When air quality deteriorates due to wildfire smoke, staying indoors with windows and doors closed is recommended to reduce exposure. Using air conditioning with the recirculate setting turned on can also help filter out particle pollution. For those with asthma or respiratory conditions, having inhalers and medication on hand is essential. In some cases, evacuating to an area with better air quality may be necessary, especially when the Air Quality Index (AQI) reaches hazardous levels.

Agriculture

Agricultural air pollution comes mainly in the form of ammonia, which enters the air as a gas from heavily fertilized fields and livestock waste. Ammonia emissions from livestock manure and chemicals comprise 95% of ammonia emissions, which account for 58% of the particulate matter air pollution in European cities. In addition, emissions from cattle, pig, and chicken operations release methane, nitrous oxide, and ammonia into the air. These gases can impact the environment and pose a danger to human health.

Fertilizer production has skyrocketed from about 20 million tons in 1950 to nearly 190 million tons today, with about a third of them being nitrogen-based. The production of artificial fertilizers is expected to keep growing to meet the demands of the increasing human population. While fertilizers are necessary for food production, they contribute significantly to air pollution. Excess fertilizers wash off fields each year, polluting huge watersheds.

Agricultural air pollution is not limited to the areas where crops are grown. Chemical drift with pesticides, herbicides, and fertilizers can occur as these compounds reach nearby lands or neighborhoods, contributing to poor air quality elsewhere. Furthermore, emissions from tractors and farm vehicles also add to the air pollution caused by agricultural activities.

The impacts of air pollution on agriculture are also significant. Air pollution and climate change can damage agriculture by reducing crop yields, damaging crops, and threatening food security. According to the UN Food and Agriculture Organization, crop yields of staples like rice, maize, and wheat will decrease by up to 10% per degree Celsius of global warming.

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