Causes of Air Pollution
Human Causes
Human activity and its resulting pollutants are the primary causes of air pollution today. Fossil fuels, heavy metals, waste accumulation, and modern agricultural practices are some of the major contributors. Below are the main human activities causing air pollution and their impact:
Fossil Fuel Emissions
Burning fossil fuels like oil and coal is one of the most significant causes of air pollution. Power plants, factories, waste incinerators, furnaces, and other facilities rely heavily on fossil fuel combustion. Devices like air conditioners and other appliances powered by electricity require substantial fuel consumption.
In the United States, the industrial sector is responsible for approximately 21% of greenhouse gas emissions, while electricity generation accounts for 31%. Studies from 2013 showed that transportation emitted over half of the carbon monoxide and nitrogen oxides in the air and about a quarter of the hydrocarbons released.
The 2014 IPCC Fifth Assessment Report revealed that the industrial sector contributes 21% of greenhouse gas emissions, electricity and heat production accounts for 25%, and transportation accounts for 14%.
Agricultural Emissions
Agricultural machinery used for plowing and harvesting, which depend on fossil fuels, significantly increases air pollutants. Additionally, large-scale livestock farming for food purposes releases methane gas, contributing to the greenhouse effect.
Waste
Burning waste in open areas and organic waste in landfills release large amounts of dioxins, furans, methane, and fine particles like black carbon into the atmosphere, exacerbating air pollution. Estimates suggest that about 40% of all waste is burned in open air globally.
In 166 out of 193 countries, open burning of municipal and agricultural waste is a widespread issue. Improving waste collection, separation, and disposal systems is essential to reducing the amount of waste burned and buried in landfills. Organic waste should be converted into compost or bioenergy to enhance soil fertility and provide alternative energy sources. Reducing food waste also plays a significant role in improving urban air quality.
Metal Smelting
Some industries, such as metal smelting, produce specific harmful air pollutants. Smelting, particularly lead production, significantly contributes to air pollution. The production of certain aviation fuels containing lead also exacerbates the problem.
Natural Causes
Although human activities are the primary cause of air pollution, some natural factors also contribute:
- Volcanic Activity: Releases toxic gases like sulfur and chlorine and particles like ash. However, these pollutants are usually confined to the region experiencing volcanic activity.
- Wind and Air Currents: Transport pollutants from land over vast areas.
- Wildfires: Produce carbon monoxide and fine particles containing organic pollutants like polycyclic aromatic hydrocarbons (PAHs). Although they can affect large regions, wildfires are often contained.
- Microbial Decomposition: Natural decomposition by microorganisms releases gases like methane.
- Radioactive Decay: Natural decay processes in the Earth’s crust release radon gas, which accumulates in enclosed spaces such as building basements.
- Rising Temperatures: Increase the volatilization of pollutants from contaminated soil and water into the air.
Effects of Air Pollution
Air pollution is responsible for approximately 7 million deaths annually worldwide. According to the World Health Organization (WHO), 9 out of 10 people breathe polluted air. Polluted air poses a severe threat to health and the climate, causing premature deaths due to stroke, heart disease, chronic obstructive pulmonary disease, lung cancer, and respiratory infections.
More than 80% of urban residents in monitored areas breathe air that exceeds WHO’s recommended pollution levels. Low- and middle-income cities experience higher levels of outdoor and indoor air pollution compared to wealthier areas.
For more information on atmospheric pollution, its types, remedies, and effects, refer to studies on air pollution. To learn more about environmental pollution, consult related articles.
