Estonia's air is among the cleanest in the world. However, we also have air pollution. Polluted air is a considerable environmental threat to human health. Most harmful are tiny particles from vehicle emissions, combustion processes and chemical reactions in the atmosphere. Statistics provide an overview of air emissions in Estonia and their origin, for example emissions of chemical and organic compounds and fine particles; emissions of gases caused by acid rain. The data on air pollutant emissions are used when drawing up development and action plans and for monitoring air quality.