combustion products filtration of flue gases 6 filters of solid particles 6 flueways 6 diesel engines 6 car motors 5 air pollution 5 more ... carbon dioxide 4 gases 4 abstersion of flue gases 4 absorption spectroscopy 3 analysis of gases 3 photometry 3 simulation and modelling 3 automation 2 power station wastes 2 measurement 2 environment protection 2 reduction 2 internal combustion motors 2 civil engineering 2 technical standards 2 environmental pollution 2 cleaning 2 analysis 1 atmosphere (geophysics) 1 buildings (architecture) 1 difractometry 1 transport 1 nitrogen 1 less ...