Related by context. Frequent words. (Click for all words.) 68 nitrogen oxide NOx emissions 62 sulfur dioxide SO2 62 nitrous oxides 61 smog forming pollutants 61 nitrogen oxides NOx 61 nitrogen NOx 61 smog forming nitrogen oxides 60 nitrogen oxide NOx 60 sulfur dioxide nitrogen oxide 59 particulate matter emissions 59 sulfur oxide 58 greenhouse gases GHG 58 particulate matter PM 58 particulate emissions 58 nitrogen oxide emissions 58 CO ² emissions 58 8 CYL 58 NOx emissions 57 sulfur hexafluoride 57 nitrogen oxide 57 Selective Catalytic Reduction SCR 56 Nitrogen oxides 56 pollutants emitted 56 particulate filters 56 NOx 55 sulfur dioxide nitrogen oxides 55 smog forming 55 SO2 emissions 55 emmissions 55 diesel particulate filter 55 exhaust emissions 54 6 CYL 54 CO2 emissions 54 Particulate Matter 54 pollutant emissions 54 nitrogen trifluoride 54 heat trapping gases emitted 54 particulate filter 53 gas recirculation 53 carbon dioxide emissions 53 Diesel exhaust 53 nitrogen oxides 53 diesel particulate matter 52 carbon dioxide emission 52 conventional internal combustion 52 greenhouse gases GHGs 52 exhaust emission 52 emission 52 nitrous oxide emissions 51 CO2 emission 51 EMISSIONS 51 gas recirculation EGR 51 GHG emission 51 Emitting 51 mpg city/# highway 51 potent greenhouse gas 51 NF3 51 greenhouse gasses 51 carbon dioxide CO2 51 Co2 emissions 51 #g/km CO2 [001] 51 CO2 Emissions 51 fluorocarbons 51 emissions 50 sulfur oxides 50 diesel particulate filters 50 carbon dioxide methane nitrous 50 co2 50 Emissions Reduction 50 CO -2 50 CO2 50 B# biodiesel [002] 50 SF6 50 reducing CO2 emissions 50 SOx 50 greenhouses gases 50 luminous flux 50 Ti VCT 50 evaporative emissions 50 selective catalytic reduction 50 Carbon dioxide emissions 49 CO ² 49 Particulates 49 variable valve 49 BlueTec 49 Dual Fuel 49 reduce carbon emissions 49 AMD PowerNow 49 tailpipe emissions 49 adipic acid 49 turbodiesel engine 49 produces #bhp 49 atmospheric pollutants 49 gaseous emissions 49 heat trapping carbon dioxide 49 C# emissions 49 greenhouse gases 49 carbon dioxide CO2 emissions 49 absorbs carbon dioxide 49 Emission Reduction 49 Oxides