Related by context. Frequent words. (Click for all words.) 60 sulfur dioxide nitrogen oxide 59 smokestack emissions 59 pollution 57 sulfur dioxide emissions 56 SO2 emissions 56 sulfur dioxide 55 coal fired 55 particulate matter emissions 55 gasifiers 55 selective catalytic reduction 55 pollutants emitted 55 pollutants 54 flue gases 54 nitrogen oxide emissions 54 cement kiln 54 air pollution 54 scrubbers 54 sulfur dioxide nitrogen oxides 53 sulfur dioxide SO2 53 nitrous oxides 53 scrubber 53 nitrogen oxides 52 polluted groundwater 52 CO -2 52 pollutant emissions 52 coal gasification 52 sulfur oxide 52 emmissions 52 SO2 52 emission 52 particulate emissions 52 Scrubbers 52 mercury emissions 52 particulate filters 51 emissions 51 coke ovens 51 cleaner burning 51 desulfurization 51 smog forming 51 nitrogen oxides NOx 51 polluting 50 mercury pollution 50 nitrogen oxide 50 nitrogen oxide NOx 50 coal combustion 50 diesel particulate filters 50 carbon dioxide 50 noxious odors 50 flyash 50 desulphurisation 50 combustion turbine 50 flue gas 49 Controlled burns 49 NOx 49 coal 49 Selective Catalytic Reduction SCR 49 acid rain 49 carbon dioxide emissions 49 combustion 49 noxious chemicals 49 NF3 49 methylene chloride 49 evaporation ponds 48 anaerobic digesters 48 baghouse 48 Sulfur dioxide 48 diesel particulate filter 48 greenhouse gases 48 harmful contaminants 48 particulate filter 48 perchlorethylene 48 combustion turbines 48 hydrogen chloride 48 steam boiler 48 dehumidifying 48 soot particles 48 air toxics 48 toxic chemicals 48 NOx emissions 48 incinerators 48 chemical solvents 47 Carbon sequestration 47 smokestacks 47 harmful pollutants 47 VOC emissions 47 CO2 47 fly ash 47 SF6 47 heat trapping gasses 47 Integrated Gasification Combined Cycle 47 fine particulate 47 gasoline vapors 47 diesel particulate matter 47 photovoltaic arrays 47 fluorescent lamp 47 pulverized coal 47 exhaust emission 47 contaminating groundwater 47 smog forming emissions 47 evaporative 47 boilers