Air pollution is defined as the contamination of indoor or outdoor environments by any chemical, physical, or biological agent that alters the natural characteristics of the atmosphere. WHO data show that 99% of the global population breathes air that exceeds its recommended guideline limits, with particularly high exposure levels in low- and middle-income countries.

According to the World Bank, air pollution is the leading environmental risk to human health, responsible for 7 million premature deaths annually. It also imposes significant medical and productivity costs, posing a serious threat to national development goals.

In Iran, air pollution, especially in major cities like Tehran, presents growing environmental, economic, and public health challenges. Key contributors include rapid urbanization, industrial emissions, and heavy traffic congestion.