Pollution is the introduction of contaminants into the natural environment that cause adverse changes. Air pollution occurs when harmful substances affect the atmosphere, potentially causing health issues and environmental damage. Air pollutants come from natural sources like wildfires and volcanoes, or human sources such as vehicle emissions, industrial operations, and waste disposal. Air pollution has wide-ranging negative health effects and contributes to issues like acid rain, global warming, and ozone depletion. Efforts to reduce air pollution include emissions controls, land use planning, and environmental impact assessments.