Keywords: Transportation pollution.svg Bar chart showing CO2 0 01 NOX and SO2 10 pollution in grams per tonne-kilometer of cargo from truck transport train transport and ship transportation Data taken from OECD The Environmental Effects of Freight http //www oecd org/dataoecd/14/3/2386636 pdf Pollution Transport Sulfur dioxide Railway Statistics 2005-12-04 own assumed Bertil~commonswiki |