Air quality has a major impact on health, the environment, and the overall well-being of people. Two indicators are used to monitor air quality: Concentrations of fine particles in the air (particulate matter PM), and nitrogen dioxide (NO2). Both are considered by the World Health Organization (WHO) as major air pollutants with significant negative effects on respiratory and cardiovascular systems. Recent PM10 data for Europe show that across Eastern European countries, as well as Belgium, Greece, the Netherlands and Italy, a large share of population is exposed to elevated values of parti-culate matter above an annual average concentration of 20 μg/3. According to the WHO guidelines, the risk of adverse effects on health is very high above this threshold of annual average exposure ().