'Smoging kills' - Effects of air pollution on human respiratory system.

Atmospheric pollution suspended in humid air is popularly known as 'smog'. It is composed of dust particles of different sizes, as well as non-metal oxides, organic compounds, and heavy metals. Exposure to harmful substances suspended in the air - apart from, for example - smoking cigarettes, one of the modifiable factors leading to the development of respiratory diseases. There are six types of substances present in the air that have a negative impact on public health and result in significant consequences: ozone, particulate matter (PM) of different diameters - PM2.5µ, PM2.5‒10 µ, PM10 µ, nitrogen dioxide, sulphur dioxide, carbon monoxide and lead. Particular attention is given to small dust particles (PM10 and PM2.5) because they can penetrate into the lower respiratory tract. Apart from describing the composition of smog and sources of air pollution, the article also discusses the impact of atmospheric pollutants on both development and aggravation of the symptoms of such respiratory tract diseases as asthma, chronic obstructive pulmonary disease, respiratory infections and lung cancer. Some of legal measures applied in different countries aimed at reducing exposure to noxious air pollutants are reviewed. The authors believe that the increased focus on risks arising from inhaling toxic air pollution may be a first step for developing systemic solutions aimed at resolving or, at least, decreasing those risks.