exhaust gases 41 internal combustion motors 13 air pollution 11 cars 9 compression ignition engines 9 filtration 6 additives 6 more ... urethans 6 car motors 4 issues 4 environment protection 4 contaminants 4 spark-ignition engines 4 biofuels 3 imissions 3 fuels (transport) 3 technical standards 3 transport 2 emise znečišťujících látek 2 ethylalcohol 2 catalysts 2 air transport 2 air cleanness monitoring 2 diesel engines 2 personal cars 2 nitrogen oxides 2 road transport 2 simulation and modelling 2 greenhouse effect 2 combustion 2 less ...