Revised estimates of total global anthropogenic mercury emissions to air ( tonnes ) from ` by-product ' and ` intentional-use ' emission sectors in 1990 , 1995 , 2000 and 2005 . ( WD = Waste Disposal , CSP = Caustic Soda Production ) ( Source : AMAP , 2010 ) In the left bar for each year shows the revised estimates of ` by-product ' emissions for the respective years .