Related by context. Frequent words. (Click for all words.) 73 particulate emissions 68 emissions 68 NOx emissions 68 emission 67 tailpipe emissions 63 CO2 emissions 63 NOx 62 CO2 emission 60 diesel engines 60 Emissions 59 diesels 58 carbon dioxide emissions 58 nitrogen oxides 57 carbon dioxide emission 57 pollution 56 nitrogen oxide emissions 56 air pollution 56 pollutants 56 Emission 56 nitrogen oxide 55 particulates 55 exhaust fumes 55 VOCs 55 particulate matter 55 greenhouse gas emissions 55 carbon emission 55 greenhouse gas emission 55 greenhouse emissions 55 diesel 55 greenhouse gasses 54 diesel powered 54 carbon emissions 54 GHGs 53 combustion engine 53 carbon dioxide CO2 emissions 53 GHG emissions 53 reducing CO2 emissions 53 exhaust gases 52 CO2 52 emission reduction 52 driveability 52 greenhouse gases 51 zero emission 51 diesel exhaust 51 particulate 51 greenhouse gas 51 diesel engine 51 internal combustion engine 50 volatile organic compounds 50 catalytic converters 50 particulate pollution 50 drivability 50 pollutant 50 internal combustion engines 49 combustion 49 g km 49 mileage 49 greenhouse gas GHG emissions 49 combustion engines 48 polluting 48 carbon dioxide CO2 48 CARB 48 #g/km [002] 48 CAFE standards 47 nitrogen dioxide 47 VOC 47 emission reductions 47 catalytic converter 47 tailpipe 47 hybrid powertrain 46 emission norms 46 SO2 46 emitting 46 global warming gases 46 Clean Diesel 46 reduce carbon emissions 46 carbon emitting 46 tailpipes 45 mpg 45 cleaner fuels 45 carbon dioxide 45 GHG 45 mercury emissions 45 reducing carbon emissions 45 #mpg [002] 45 sulfur dioxide emissions 44 electric hybrids 44 fuel injectors 44 smog 44 powertrains 44 environmental friendliness 44 Pollution 44 hybrid electric 44 DPF 44 internal combustion 44 diesel fumes 43 carbon dioxide emitted 43 carbon footprints 43 turbocharging 43 cleaner burning 43 electric motor