Harmful Gases: Air Pollution's Causes And Effects

Harmful gases are released into the air through human activities such as industry and transportation, as well as natural factors. These gases, including nitrogen oxide, carbon dioxide, sulphur oxide, and toxic chemicals like hydrogen sulfide and benzene, contribute to air pollution and pose risks to human health and the environment. The concentration of these gases in the atmosphere, measured in parts per million, can lead to undesirable effects on people and the planet. With climate change as a pressing concern, understanding the sources and impacts of harmful gases is crucial for mitigating their release and protecting our planet.

Poorly maintained appliances

Poor maintenance of appliances can lead to harmful gases being released into the air. This is particularly true of gas appliances, which can emit toxic compounds such as carbon monoxide, nitrogen oxides, and methane. These gases are known to have adverse effects on human health, including respiratory issues and, in extreme cases, death.

Gas cooktops and ovens have been found to negatively impact indoor air quality, with cooking on gas stoves releasing nitrogen dioxide and additional tiny airborne particles known as PM2.5. These pollutants are linked to an increased risk of asthma in children, with children living in households that cook with gas 42% more likely to develop the condition. Furthermore, gas appliances introduce other toxic chemicals into homes, with 21 hazardous air pollutants identified in unburned gas from stoves and pipelines in one study.

Heating devices and water heaters can also pose a danger when their toxic gases are drafted into the home instead of being vented outdoors. This can occur due to problems with ventilation, such as a blocked or poorly designed chimney, or when other ventilation fans are operating, reducing indoor air pressure. Incomplete combustion of fuel in a poorly maintained furnace or boiler burner can result in low burner temperatures and the release of harmful gases.

To mitigate these risks, it is crucial to properly maintain gas appliances and ensure adequate ventilation. Range hoods, for example, can help capture and vent out lighter gases, although they may struggle with heavier gases like nitrogen oxides. Regular maintenance checks can help identify and resolve any issues, such as leaks or blockages, that may lead to improper venting of combustion gases.

In the long term, transitioning from gas to electric appliances is recommended to improve indoor and outdoor air quality. Electric appliances do not rely on methane gas and can utilize renewable, clean energy sources, reducing the impact on the environment and human health.

Industrial and refinery emissions

Industrial emissions and refinery emissions are significant contributors to the presence of harmful gases in the air. The industrial sector, including manufacturing, food processing, mining, and construction, accounts for nearly 30% of U.S. greenhouse gas emissions. These emissions arise from diverse processes, such as the combustion of fossil fuels for heat and power, chemical reactions necessary for producing goods from raw materials, and the non-energy use of fossil fuels. Oil and gas production is the largest human-made source of methane in the United States.

Refineries, particularly oil refineries, are a notable source of atmospheric pollutants. The refining processes release gases such as carbon monoxide, a colorless and odorless gas that can be deadly; sulphur dioxide, which has an irritating effect on the respiratory system; nitrogen oxides, which are a significant contributor to air pollution and reduced air quality; and volatile organic compounds. Oil refineries also emit high concentrations of suspended particles, a combination of small chemicals in solid and liquid states, which can have detrimental effects on both nearby communities and distant ecosystems.

The combustion of oil, coal, and gasoline during refining processes produces over a hundred substances that contribute to air quality deterioration. These substances can combine with dust particles and react with sunlight and other airborne compounds, leading to various health issues. Prolonged exposure to the resulting polycyclic aromatic hydrocarbons (PAHs) can cause skin and eye problems, possess a high carcinogenic potential, and weaken the immune system.

To mitigate the environmental impact of industrial and refinery emissions, various strategies can be employed. These include improving energy efficiency, transitioning to renewable energy sources, implementing carbon capture and storage technologies, and enhancing the efficient use and recycling of materials. Regulatory approaches, such as the Clean Air Act and the EPA's methane emissions rule, also play a crucial role in reducing harmful emissions.

Fossil fuel combustion

Carbon dioxide, a greenhouse gas, is one of the primary emissions from fossil fuel combustion. It is the most significant human-produced climate-altering greenhouse gas. The Annual Greenhouse Gas Index, used to track the warming influence of long-lived climate-altering greenhouse gases, increased by 40% from 1990 to 2016, with the majority of this increase attributed to rising CO2 levels. CO2 levels in the atmosphere are currently at their highest in 800,000 years. Carbon dioxide emissions contribute to the greenhouse effect, which intensifies the re-radiation of heat in the atmosphere and increases the Earth's average air temperatures.

Sulfur dioxide and nitrogen oxides are also released into the atmosphere as a result of fossil fuel combustion. These gases react with water vapor, oxygen, and other chemicals to form acid rain. Acid rain can contaminate freshwater sources, leading to harmful algal blooms that reduce water oxygen levels and harm aquatic life. Additionally, acid rain increases the chemical weathering of rocks and man-made structures.

The burning of fossil fuels also emits an array of pollutants that reduce air quality and harm human health. These pollutants include nitrogen oxides, which are the main contributors to reduced air quality. Nitrogen oxides can cause eye, skin, and respiratory tract irritation and, in high enough concentrations, can be lethal. Fossil fuel combustion also releases airborne particles such as soot, which increase the reflectivity of the atmosphere and contribute to respiratory illnesses.

The combustion of fossil fuels has been identified as the dominant cause of global warming and climate change. In 2018, 89% of global CO2 emissions came from fossil fuels and industry. Coal is the most polluting fossil fuel, responsible for over 0.3 degrees Celsius of the 1-degree increase in global average temperatures. Oil releases a significant amount of carbon when burned, contributing to about a third of the world's total carbon emissions. Natural gas, while promoted as a cleaner alternative, is still a fossil fuel and accounts for a fifth of global carbon emissions.

Natural and chemical reactions

Natural Sources

Ozone (O3) is a toxic gas that occurs naturally in the upper atmosphere of the stratosphere. It is made up of three oxygen atoms and is often seen as widespread smog across cityscapes. While natural processes produce ozone, human activities can also contribute to its formation. Chemical reactions resulting from vehicle exhausts or gasoline vapors, for example, can lead to high concentrations of ozone at ground level. This gas is harmful to both plant life and humans, causing health issues such as decreased lung function, respiratory infections, UV overexposure, and skin cancer.

Volcanic activity is another natural source of harmful gas emissions. Volcanic eruptions release various gases, including sulfur dioxide (SO2), carbon dioxide (CO2), hydrogen sulfide (H2S), and hydrogen chloride (HCl). These gases can have detrimental effects on the environment and human health.

Chemical Reactions

Human activities involving chemical reactions are a significant source of harmful gas emissions. The burning of fossil fuels, such as in vehicles and power plants, releases gases like nitrogen oxides (NOx) and carbon monoxide (CO). Nitrogen oxides, including nitric oxide (NO) and nitrogen dioxide (NO2), are major contributors to air pollution and reduced air quality. They are emitted from vehicles, agricultural processes, and the combustion of fossil fuels.

In addition, certain industries and manufacturing processes emit toxic gases as byproducts. For example, hydrogen sulfide, a highly toxic gas with a "rotten egg" smell, is produced in various manufacturing processes, including pesticides, plastics, pharmaceuticals, and breweries. Inhalation of high concentrations of hydrogen sulfide can lead to irritation, unconsciousness, memory loss, and even death.

Chemical releases during accidents at industrial facilities or during the transport of hazardous materials can also result in the release of toxic gases into the atmosphere.

Transportation

Cars, trucks, and buses produce air pollution throughout their life cycle, including during vehicle operation and fuel production. The transportation sector emits more than half of the nitrogen oxides in our air and is a major source of heat-trapping emissions. Nitrogen oxides, along with particulate matter and volatile organic compounds, contribute to poor air quality, which negatively impacts the health and welfare of citizens. Pollutants from vehicle exhausts have been linked to adverse impacts on almost every organ system in the body, and exposure to this pollution disproportionately affects Latinos, Blacks, and lower-income households.

To combat these issues, the US Environmental Protection Agency (EPA) has implemented various strategies. The EPA has developed international carbon dioxide emissions standards for aircraft in collaboration with the Federal Aviation Agency and the United Nations' International Civil Aviation Organization. The EPA is also working towards setting domestic regulations under the Clean Air Act to address greenhouse gas emissions from specific engine classes used in aircraft. The Diesel Emissions Reduction Act program offers grants, rebates, and support for projects that improve air quality and protect human health by reducing harmful emissions from diesel engines. The EPA's Clean School Bus Program provides funding to replace existing school buses with zero-emission and low-emission models.

Furthermore, the EPA and the Department of Transportation (DOT) have issued joint regulations for fuel economy and greenhouse gas emissions for cars, light trucks, and heavy-duty trucks. These regulations are expected to significantly reduce greenhouse gas emissions and improve fuel efficiency. The EPA also provides information and resources to help states and local areas achieve their air quality and transportation goals, including emission reduction strategies, national policies, regulations, incentive-based programs, and funding sources.

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