Air Pollution: Unnatural Sources And Their Impact

Air pollution is the presence of harmful substances in the air, which can be caused by both human and natural sources. While natural sources of air pollution include wildfires, dust storms, and volcanic eruptions, human sources such as the burning of fossil fuels, vehicle emissions, and industrial processes contribute significantly to the degradation of air quality. The impact of air pollution is evident in the approximately 7 to 8 million premature deaths it causes annually, making it a critical global health and environmental concern.

Wildfires

Particulate matter, or particle pollution, is a primary concern when it comes to wildfire-induced air pollution. Fine particles, those with a diameter of 2.5 micrometres (PM2.5) or smaller, are the main pollutant emitted by wildfires. These particles can remain suspended in the air and travel long distances, affecting areas far from the fire source. PM2.5 particles can aggravate asthma, trigger lung disease, cause heart attacks, and contribute to premature deaths. They are of particular concern due to their small size, which allows them to reach the bloodstream when inhaled.

Additionally, wildfires produce nitrogen oxides, particularly nitrogen dioxide (NO2), which is a reddish-brown toxic gas with a strong odour. Nitrogen oxides can form acid rain, cause haze, and lead to nutrient pollution in water bodies. They are formed through the burning of fossil fuels and biomass, as well as during lightning strikes.

The impact of wildfires on air quality can be long-lasting and far-reaching. Research has shown that wildfire smoke exposure increases the risk of both cardiovascular and respiratory health issues. The intensity of the smoke and the duration of exposure play a role in the severity of health effects. Wildfires can also reduce visibility, as the smoke and particulate matter create haze in the atmosphere.

Climate change and wildfires have a mutually exacerbating relationship. As global temperatures rise, conditions become more favourable for wildfires, leading to increased drought and stronger winds, resulting in hotter and longer fire seasons. At the same time, wildfires contribute to climate change by releasing large amounts of greenhouse gases and ravaging carbon-rich ecosystems, such as peatlands.

Volcanic eruptions

Volcanic ash is a primary pollutant, formed of solid particles and liquid droplets, that is dispersed and carried by gases into the earth's atmosphere. The size of the ash particles influences the reach of the ash cloud, with smaller particles allowing the cloud to extend further and disperse more widely. For example, the 1980 eruption of Mount St. Helens released an ash cloud that travelled across the United States in three days and reached the rest of the world in 15 days.

Volcanic gases, such as carbon dioxide, sulphur dioxide, and sulphuric acid, are also released during eruptions. These gases can have significant impacts on the environment and human health. Carbon dioxide, due to its weight, remains close to the Earth's surface, impacting the biosphere. Sulphur dioxide contributes to the formation of acid rain, which affects terrestrial ecosystems and human populations, causing irritation to the nose, throat, eyes, and skin.

The United States Geological Survey (USGS) has studied the health impacts of volcanic emissions, noting that the World Health Organization recommends a maximum exposure of 0.5 ppm of sulphuric acid over 24 hours. Higher concentrations can lead to immediate irritation of the nose, throat, eyes, and skin.

The effects of volcanic eruptions on air quality can be widespread and long-lasting. The 1986 eruption of Mt. Kilauea in Hawaii released about 2,000 tonnes of sulphur dioxide into the lower troposphere, resulting in persistent acid rain and air pollution issues downwind from the vent. Volcanic eruptions can also impact indoor air quality, as ash and gases can infiltrate homes and buildings, posing risks to human health, especially for those with respiratory issues.

Industrial processes

Refineries and Petrochemical Plants

Refineries and petrochemical plants process hydrocarbons, primarily from crude oil and natural gas, to produce fuels, chemicals, plastics, synthetic fibres, fertilizers, and pharmaceuticals. These facilities emit pollutants such as PM2.5, sulfur dioxide, nitrogen oxides, volatile organic compounds (VOCs), carbon monoxide, and hazardous air pollutants (HAPs) like benzene, toluene, and xylene.

Steel Making Plants

Steel making plants, or steel mills, produce steel from raw materials. They are a source of pollutants such as PM2.5, which can cause respiratory and cardiovascular issues, as well as contribute to smog and acid rain.

Mining Activities

Mining releases airborne pollutants including PM2.5, silica dust, coal dust, methane, carbon monoxide, sulfur dioxide, nitrogen oxides, heavy metals (e.g., mercury and lead), and VOCs from explosives and chemicals. These pollutants have severe health impacts, including silicosis, black lung disease, and toxic effects from heavy metals.

Power Plants

Power plants, particularly those burning fossil fuels, emit pollutants that contribute to air pollution. This includes the release of carbon dioxide, a major greenhouse gas contributing to climate change, as well as nitrogen oxides, which can form acid rain and haze.

Waste Management

The waste disposal industry can generate hazardous waste that requires proper disposal at specialized facilities. Inadequate waste management can lead to significant air pollution, especially through waste incineration.

Agriculture

Agricultural practices, including the burning of biomass and agro-waste, contribute to air pollution. This releases particulate matter, carbon dioxide, and other pollutants into the atmosphere, impacting air quality and human health.

The above industrial processes are significant contributors to air pollution, and efforts to mitigate their impact are crucial to improving air quality and protecting public health.

Fossil fuels

The burning of fossil fuels releases carbon dioxide, nitrogen oxides, and other greenhouse gases, contributing to global warming and climate change. According to the US Environmental Protection Agency, the combustion of fossil fuels is a significant source of nitrogen oxides, which form smog and acid rain. These emissions have detrimental effects on air quality and human health, with nitrogen oxides being particularly harmful.

Additionally, the extraction and infrastructure associated with fossil fuels contribute to pollution. For instance, thousands of oil spills occur annually in the United States, threatening ecosystems and human health. Leaks from natural gas plants, wells, and pipelines emit methane, a potent greenhouse gas. The practice of strip mining, prevalent in coal extraction, destroys ecosystems and releases vast amounts of carbon stored in the soil.

Furthermore, the combustion of fossil fuels contributes to particle pollution. Particulate matter, composed of microscopic solid particles or droplets suspended in a gas, poses significant health risks, especially the smaller particles that can reach the bloodstream. A 2017 study found that 17.6 million Americans are exposed daily to toxic air pollution from active oil and gas operations, including carcinogens and chemicals linked to blood disorders.

The transition away from fossil fuels is imperative to mitigate their harmful impacts. Embracing renewable energy sources, such as hydropower, wind, and solar power, can help reduce carbon emissions and improve air quality. Additionally, improving energy efficiency and transitioning to cleaner technologies are crucial steps toward a more sustainable and environmentally friendly energy system.

Vehicles

Cars, trucks, and buses produce air pollution throughout their life cycle, including pollution emitted during vehicle operation and fuel production. Additional emissions are associated with the refining and distribution of fuels and, to a lesser extent, manufacturing and disposal or recycling of the vehicle. The burning of gasoline in cars emits pollutants such as carbon monoxide, nitrogen oxides, and soot. These pollutants have significant risks for human health, especially for people who live near busy roads, and the environment. Exposure to pollution from vehicles is inequitable, disproportionately affecting Latinos, Blacks, and lower-income households.

Diesel exhaust is a major contributor to particulate matter (PM) pollution. PM pollution includes all airborne substances that are not gases, such as microscopic solid particles or droplets suspended in a gas. Smaller particles pose more risk to human health as they can reach the bloodstream. Fine particles from diesel exhaust are less than one-tenth the diameter of a human hair and can penetrate deep into the lungs, causing respiratory problems.

Volatile organic compounds (VOCs) emitted from cars, trucks, and buses are another type of pollutant linked to different types of cancer. These include toxic air pollutants such as benzene, acetaldehyde, and 1,3-butadiene. Furthermore, when VOCs react with nitrogen oxides in the presence of sunlight, they form ground-level ozone, a main ingredient in smog. While beneficial in the upper atmosphere, ground-level ozone irritates the respiratory system, causing coughing, choking, and reduced lung capacity.

To address vehicle emissions and reduce air pollution, the Environmental Protection Agency (EPA) has implemented various programs and standards. These include the Diesel Emissions Act Reduction program, which provides funding for projects that reduce harmful emissions from diesel engines. The EPA has also set standards for smog, soot, and other air pollutants, as well as created programs that lead to investments in clean vehicle and engine technology. By 2030, EPA air quality emissions standards for vehicles are projected to have a significant positive impact on air quality and public health.

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