Related by context. Frequent words. (Click for all words.) 51 fossil fuels 51 fossil fuel 49 nitrous oxides 48 polluting 48 dioxide 48 cleaner burning 47 cleaner fuels 47 nitrogen fertilizers 46 greenhouses gases 46 coal fired 46 smog 46 air pollution 46 greenhouse gases 45 Fossil fuels 45 greenhouse gasses 45 greenhouse gas 45 pollution 45 emissions 45 emission 45 carbon emitters 44 pollutant emissions 44 carbon dioxide emission 44 curbing greenhouse gases 44 burning fossil fuels 44 Carbon dioxide emissions 43 greenhouse emissions 43 biomass fuels 43 carbon emitting 43 Longannet 43 absorbing carbon dioxide 43 coal 43 heat trapping carbon dioxide 43 greenhouse gas emitting 42 Greenhouse gases 42 renewable energies 42 greenhouse gas emission 42 electricity 42 greenhouse gas emissions 42 particulate matter emissions 42 GHGs 42 smokestack emissions 42 nonpolluting 42 carbon dioxide emissions 42 carbon emission 42 tailpipe emissions 41 renewables 41 greenhouse gas emitters 41 hydrocarbon fuels 41 E.On s 41 soot particles 41 polluters 41 smog forming emissions 41 sulfur dioxide 41 diesel 41 carbon emissions 41 reducing carbon emissions 41 natural gas 41 carbon dioxide 41 global warming 40 emit carbon dioxide 40 GHG emission 40 greenhouse gas emitter 40 Sulfur dioxide 40 exhaust emissions 40 nitrogen oxide emissions 40 pollutant 40 fuels 40 nitrogen oxides NOx 40 NGVs 40 asthma bronchitis 40 polluting industries 40 exhaust emission 40 ozone depleting chemicals 40 nitrogen oxide NOx 40 energy 40 lignite coal 40 nitrous oxide emissions 40 carbon emitter 39 warming gases 39 methyl tertiary butyl ether 39 global warming gases 39 particulate emissions 39 biofuel crops 39 CO2 emission 39 CO2 39 HCFC 39 alternative fuels 39 internal combustion engines 39 CO2 emissions 39 reformulated gasoline 39 combustion engine 39 fuel 39 harmful gases 39 reducing CO2 emissions 39 SO2 39 atomic reactors 39 emitting 39 carbons 39 electricity grids 39 emitters 39 biofuels