air pollution 326 air cleanness monitoring 82 environment protection 42 health harmful substances 36 imissions 29 issues 28 contaminants 24 more ... environmental pollution 19 aerosols 18 atmosphere (biology) 17 environmental hygiene 16 environment 16 measurement 15 dust particles 15 combustion 15 atmosphere (geophysics) 12 internal climate 12 industrial air conditioning 10 exhaust gases 10 air cleaners 10 aromatic polycyclic hydrocarbons 9 climatic changes 9 Earth warming 9 internal combustion motors 9 water pollution 9 anthropogenic contamination of atmosphere 8 biofuels 8 mathematical models 8 carbon dioxide 8 simulation and modelling 8 less ...