Human Activities: The Air Polluters

Air pollution is a major threat to global health and prosperity, causing more than 6.5 million deaths each year. It is caused by the release of pollutants into the atmosphere, which are detrimental to human health and the planet. Burning fossil fuels, including coal, natural gas, and oil, is the primary source of air pollution. This happens through vehicle emissions, fuel oils, and natural gases used to heat homes, as well as by-products of manufacturing and power generation. Other sources include cigarette smoke, construction materials, and indoor activities like cooking, dry cleaning, and painting. These activities release harmful gases and particles, such as carbon dioxide, nitrogen oxides, sulfur dioxide, and particulate matter, into the atmosphere, leading to smog, acid rain, and global warming.

Burning fossil fuels for transport, electricity and industry

Burning fossil fuels for transport, electricity, and industry is a major source of air pollution. Fossil fuels include coal, natural gas, and oil. When these fuels are burned, they release harmful chemicals and gases into the atmosphere, such as carbon dioxide (CO2), nitrous oxide (N2O), and sulfur dioxide. These gases can remain in the atmosphere for decades to centuries, intensifying the greenhouse effect and increasing the Earth's average air temperatures.

Transportation, such as cars, trucks, airplanes, and ships, relies heavily on fossil fuels. Vehicles with internal combustion engines, particularly those running on diesel, emit fine particulate matter, which includes toxic pollutants such as benzene, formaldehyde, and polycyclic aromatic hydrocarbons (PAHs). These pollutants have been linked to various health issues, including childhood leukemia, blood disorders, and respiratory illnesses.

The burning of fossil fuels for electricity generation, such as in power plants, also contributes significantly to air pollution. Coal-fired power plants, in particular, release pollutants such as sulfur dioxide, nitrogen oxides, and soot. These emissions reduce air quality and have harmful effects on human health, including respiratory diseases and cardiovascular problems.

Industries, including factories and manufacturing facilities, often use fossil fuels for energy and in their production processes. The combustion of fossil fuels in these settings releases harmful pollutants into the atmosphere, contributing to smog formation. Smog, a mixture of smoke and fog, irritates the eyes and throat and damages the lungs, especially in vulnerable individuals such as children and the elderly.

Additionally, the extraction and production of fossil fuels contribute to air pollution. Mining operations, such as coal mining, can release toxic runoff into waterways and generate enormous volumes of wastewater containing pollutants. Oil spills and leaks during extraction or transport can also contaminate drinking water sources and ecosystems.

The transition to sustainable and renewable energy sources for transport, electricity generation, and industry is crucial to mitigating the environmental and health impacts of burning fossil fuels. This includes adopting clean technologies, improving energy efficiency, and utilizing renewable power sources such as solar, wind, or hydropower.

Vehicle emissions

Carbon monoxide is a significant concern, with vehicle emissions being the largest source of this pollutant across the United States. In cities, this figure rises even higher, with up to 95% of carbon monoxide emissions attributed to transportation. Similarly, the transportation sector is responsible for 45% of nitrogen oxide pollution nationwide, with California's transportation sector contributing nearly 80% of nitrogen oxide pollution and smog-causing pollutants. Diesel vehicles are a notable contributor, responsible for 60% of nitrogen oxide emissions in the US.

Benzene, a known carcinogen, is also predominantly emitted by vehicles. Exposure to benzene has been linked to leukemia, blood disorders, infertility, asthma, and increased risks of heart and lung disease. It is particularly harmful to children, with links to developmental delays and adverse effects on academic performance. Living near busy roads or commuting long distances further exacerbates these health risks.

Overall, vehicle emissions have severe impacts on human health and the environment. With approximately 17,000 to 20,000 deaths attributed to vehicle pollution each year in the US, it is crucial to address this issue through regulatory measures, fuel efficiency improvements, and the adoption of cleaner vehicle technologies.

Industrial processes

Mining activities, for instance, release numerous airborne pollutants, including PM2.5, silica dust, coal dust, methane, carbon monoxide, sulfur dioxide, nitrogen oxides, heavy metals, and volatile organic compounds (VOCs). These pollutants have detrimental effects on both the environment and human health.

Petrochemical plants, which process hydrocarbons derived from crude oil and natural gas into petrochemicals used in everyday products, emit pollutants such as PM2.5, sulfur dioxide, nitrogen oxides, VOCs, carbon monoxide, and hazardous air pollutants (HAPs). Refineries, which transform raw materials into fuels, chemicals, and other materials, release similar pollutants, including respiratory irritants and carcinogens like benzene.

Other industrial processes, such as iron, steel, and rubber manufacturing, as well as power generation, produce polycyclic aromatic hydrocarbons (PAHs) as by-products. Nitrogen oxides, a component of motor vehicle emissions and industrial processes, have been linked to an increased risk of hemorrhagic stroke in women.

The burning of fossil fuels for electricity, heat, and transportation increases greenhouse gases, such as carbon dioxide, nitrous oxide, and methane, contributing to global warming and climate change. In addition, industrial activities often involve the use of chemicals and the generation of waste, which, if not properly managed, can result in soil and water contamination, further impacting air quality.

To mitigate the impact of industrial processes on air pollution, measures such as industrial process upgradation, energy efficiency improvements, and the adoption of cleaner technologies are necessary. Stringent laws and regulations to control emissions and waste, as well as collective and individual efforts, are crucial to reducing the air pollution caused by industrial activities.

Natural sources

Volcanoes, for instance, emit massive amounts of sulphur dioxide into the atmosphere, and were once the primary source of this atmospheric pollutant. Similarly, wildfires produce smoke that carries dangerous particulate matter, which can enter the lungs, travel through the bloodstream, and affect major organs. Prolonged exposure to such smoke can lead to serious illness and even death.

Livestock is another natural source of air pollution, as animals like cows and sheep release methane through belching and flatulence. Methane is a colourless gas produced in their stomachs when bacteria break down the food they eat. Livestock is the biggest source of methane globally, and it is the second most significant greenhouse gas, capable of causing climate change.

Indoor air pollution

Humans are increasingly spending more time indoors, in their homes, workplaces, and educational institutions. Therefore, maintaining good air quality indoors is essential to ensure good health. The World Health Organization (WHO) defines indoor air pollution as the use of inefficient and polluting fuels and technologies in and around the home, which contain a range of health-damaging pollutants, including small particles that penetrate deep into the lungs and enter the bloodstream.

Sources of Indoor Air Pollution

One of the main sources of indoor air pollution is the use of polluting fuels for cooking and heating. Around 2.1 billion people worldwide cook using open fires or inefficient stoves fuelled by kerosene, biomass (wood, animal dung, and crop waste), and coal. This generates harmful household air pollution, which was responsible for an estimated 3.2 million deaths per year in 2020, including over 237,000 children under the age of five. In developing countries, solid fuels such as wood, coal, and dung are often burned indoors for cooking and heating. Exposure to high levels of particulate matter (PM) from indoor cooking stoves has been linked to respiratory infections, asthma, heart disease, and cancer.

Tobacco smoke is another significant source of indoor air pollution, causing ten times more air pollution than diesel car exhaust. Secondhand smoke from cigarettes can increase the risk of lung cancer. Additionally, the chemicals in cleaning products can release toxic fumes, which can be harmful when inhaled and have been linked to respiratory infections, asthma, and cancer.

Indoor dust can also contain traces of heavy metals from outdoor dust, furniture, and cigarette smoke. Reducing dust levels can improve lung health and minimize exposure to harmful indoor air pollutants. Pet dander, found in animals' fur, skin, and saliva, is another source of indoor air pollution, as it can cause respiratory problems, including asthma attacks, hay fever, and allergies when inhaled.

Preventing Indoor Air Pollution

To address indoor air pollution, the WHO has developed guidelines for indoor air quality and household fuel combustion, recommending clean fuels and technologies such as solar, electricity, biogas, liquefied petroleum gas (LPG), natural gas, and alcohol fuels. Proper ventilation is crucial in removing polluted indoor air and replacing it with fresh, clean air from outside. Keeping indoor spaces clean, dry, and well-maintained can also help reduce indoor air pollution by preventing the growth of mould and mildew.

Frequently asked questions