airpollution

Air pollution is the contamination of the atmosphere by harmful substances released from natural or human sources. It encompasses outdoor air pollution, caused by emissions from industry, transportation, agriculture, and burning of fuels, as well as indoor air pollution from cooking, heating, building materials, and consumer products. Common pollutants include particulate matter (PM2.5 and PM10), ground-level ozone, nitrogen oxides, sulfur dioxide, carbon monoxide, and volatile organic compounds, along with metals and asbestos in some contexts. Some pollutants form as secondary pollutants after release, such as ozone and secondary organic aerosols, which can travel long distances.

Health and environmental effects are substantial. Exposure to polluted air is linked to respiratory and cardiovascular diseases, adverse birth outcomes, and premature death. It also affects the brain, ecosystems, crops, and climate by influencing atmospheric chemistry, radiation balance, and visibility.

Monitoring and policy focus on measuring pollutant concentrations and setting permissible limits. Air quality management often includes vehicle emission standards, cleaner fuels, industrial controls, and incentives for switching to cleaner energy sources. Indoor air quality is addressed through ventilation improvements, filtration, reducing combustion indoors, and controlling sources of moisture and allergens.

Global patterns vary, with higher pollution levels in densely populated and industrial regions. Transboundary pollution and climate change influence pollutant transport and behavior. International and national efforts seek to reduce emissions, protect public health, and promote sustainable development by balancing energy needs with environmental and health considerations.