Air Pollution: Understanding The Root Causes

Air pollution is a pressing issue that poses significant risks to both human health and the planet. It refers to the contamination of indoor and outdoor environments by harmful gases and particles, which can have detrimental effects on the natural characteristics of the atmosphere. These pollutants, such as particulate matter, nitrogen oxides, and sulfur dioxide, are released into the air through various human activities and natural sources. Burning fossil fuels, vehicle exhaust fumes, industrial processes, and agricultural practices are among the primary human contributors to air pollution. Natural sources include wind-blown dust, wildfires, and volcanic activity. The health impacts of air pollution are extensive, ranging from respiratory issues to cardiovascular problems, cancers, and other health complications. According to the World Health Organization (WHO), air pollution is responsible for millions of premature deaths annually, with the majority of the global population breathing air that exceeds recommended guideline limits for pollutants. Addressing air pollution requires a combination of policies, interventions, and initiatives aimed at reducing emissions, improving energy efficiency, and transitioning to cleaner alternatives.

Burning fossil fuels

The combustion of fossil fuels also releases harmful gases such as nitrogen oxides, sulphur oxides, and carbon monoxide. These gases can combine with water droplets to become acidic and fall as acid rain, which is detrimental to human, animal, and plant life. Additionally, the release of certain chemicals during the burning of fossil fuels contributes to ground-level ozone, which is a major cause of air pollution in cities and harmful to human health.

The health impacts of air pollution from burning fossil fuels are significant. Fine particulate matter, known as PM 2.5, from the combustion of fossil fuels is easily inhaled and can penetrate deep into the lungs, entering the bloodstream and causing damage to multiple organs. Long-term exposure to air pollution has been linked to respiratory disorders, heart diseases, and an increased risk of cancers, particularly affecting children, older individuals, and those on low incomes.

According to a study by Harvard University, the University of Birmingham, and the University of Leicester, an estimated 8.7 million premature deaths each year are attributed to fossil fuel air pollution. This crisis has led to calls for a transition to renewable energy sources and efforts to reduce emissions from the burning of fossil fuels, such as fuel substitution and equipment modifications in industries.

Vehicle emissions

Carbon monoxide is a particularly harmful emission, with vehicles being the largest source of this toxic gas. In the United States, vehicles account for 56% of carbon monoxide emissions nationwide and up to 95% in cities. California's transportation sector is responsible for nearly 80% of the state's nitrogen oxide pollution and pollutants that cause smog. Diesel vehicles, in particular, contribute significantly to nitrogen oxide emissions, accounting for 60% of such emissions in the US.

Furthermore, volatile organic compounds (VOCs) found in vehicle emissions react with nitrogen oxides in the presence of sunlight to form ground-level ozone, a key ingredient in smog. While ozone in the upper atmosphere is beneficial, ground-level ozone irritates the respiratory system, causing coughing, choking, and reduced lung capacity. Smog, a mixture of particles and gases in the air, reduces visibility and makes breathing difficult, causing irritation to the eyes, nose, and throat.

To address vehicle emissions and improve air quality, various measures have been implemented. The United States' Clean Air Act and other regulations have led to newer vehicles emitting less pollution than older ones. The Environmental Protection Agency (EPA) in the US has set stringent emissions standards for passenger vehicles and heavy-duty diesel vehicles, such as tractor-trailers and buses. These standards include limits on sulfur content in gasoline, which enhances the effectiveness of emissions reduction technologies. The EPA also promotes investments in clean vehicle and engine technology, aiming to further reduce emissions and improve air quality.

Industrial processes

One of the key issues is the burning of fossil fuels for energy production and transportation, with coal, oil, and natural gas being the most significant contributors. The combustion of these fuels releases greenhouse gases, such as carbon dioxide and methane, which trap heat in the atmosphere, leading to global warming and climate change. Methane leaks are also common during oil and gas drilling and production. Additionally, the burning of crude oil and coal produces sulfur dioxide (SO2), a corrosive and acidic gas that contributes to acid rain and respiratory issues.

The manufacturing and construction sectors are major industrial polluters, especially in countries like China, where they contribute more than 50% of air pollution. This is due to high emission intensity and emission factors in the industrial structure. Mining activities also release numerous airborne pollutants, including PM2.5, silica dust, coal dust, and gases like methane, carbon monoxide, sulfur dioxide, and nitrogen oxides.

Petrochemical and steel plants are also significant sources of industrial air pollution. Petrochemical plants process hydrocarbons derived from crude oil and natural gas into petrochemicals used in everyday products like plastics, synthetic fibers, fertilizers, and pharmaceuticals. However, this process releases pollutants such as PM2.5, sulfur dioxide, nitrogen oxides, VOCs, carbon monoxide, and hazardous air pollutants (HAPs). Steel mills emit similar pollutants, including PM2.5, sulfur dioxide, nitrogen oxides, heavy metals like lead and mercury, and toxic substances like dioxins and furans.

To mitigate industrial air pollution, several strategies can be employed:

• Transition to renewable energy sources: Shifting to renewable energy sources, such as wind and solar power, can significantly reduce air pollution and the associated health risks.
• Pollution control technologies: Implementing technologies like scrubbers and catalysts can help remove pollutants like NOx and SO2 from industrial emissions.
• Sustainable manufacturing processes: Designing more sustainable manufacturing processes and products can reduce the environmental impact of industrial activities.
• Stringent environmental regulations: Enforcing strict environmental standards and regulations can deter industries from polluting and encourage the adoption of cleaner practices.
• Waste management: Properly disposing of hazardous waste and opposing waste incineration can prevent the release of toxic pollutants into the atmosphere.

Wildfires

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 health effects of inhaling wildfire smoke are well documented. Individuals at higher risk of adverse health consequences include those with cardiovascular or respiratory diseases, older adults, children under 18, pregnant women, outdoor workers, and those of lower socioeconomic status. When air quality deteriorates due to wildfire smoke, staying indoors with windows and doors closed is the most effective way to reduce exposure. If possible, it is recommended to use air conditioning or air filtration systems to improve indoor air quality.

It is worth noting that about 90% of wildfires are caused by anthropogenic factors, highlighting the role of human activities in this context. Additionally, burning stubble and farm residue significantly contribute to wildfires, leading to increased PM2.5 levels in the atmosphere.

Natural sources

Wildfires, often caused by anthropogenic actions, release smoke and toxic chemicals that can remain suspended in the air for several days. These chemicals can react with other particles, such as pollen, to create smog, a type of air pollution that reduces visibility and causes respiratory issues. Additionally, the burning of stubble and farm residue contributes to wildfires, increasing the levels of fine particulate matter (PM 2.5) in the air, which has been linked to various health issues.

While natural sources of air pollution are significant, they typically do not result in persistent air pollution problems compared to human-generated sources. The impact of natural sources can vary depending on the location and time of year. For example, wind can disperse air pollutants over short or long distances before they cause harmful effects, affecting areas downwind of pollution sources.

It is worth noting that natural sources of air pollution can interact with human activities to exacerbate the issue. For instance, the combination of aerosols with ozone, a gas commonly found in cities, forms smog. While ozone in the upper atmosphere protects us from harmful solar radiation, ground-level ozone, formed by the interaction of sunlight with emissions from burning fossil fuels, is detrimental to human health.

Frequently asked questions