"Figure 19: Acid rain precursor emissions: by type of gas, 1990 to 2012","" "United Kingdom","" "","" "Notes","1. Excluding natural world" "Unit","Million tonnes of sulphur dioxide equivalent" "","" "Acid rain precursor","Sulphur dioxide","Nitrogen oxide(1)","Ammonia(1)","Total(1)" "1990","4.0","2.3","0.6","6.9" "1991","3.8","2.2","0.7","6.7" "1992","3.7","2.2","0.6","6.5" "1993","3.4","2.0","0.6","6.0" "1994","2.9","2.0","0.6","5.5" "1995","2.6","1.9","0.6","5.1" "1996","2.3","1.9","0.6","4.8" "1997","1.9","1.7","0.6","4.3" "1998","1.9","1.7","0.6","4.2" "1999","1.5","1.6","0.6","3.7" "2000","1.4","1.5","0.6","3.6" "2001","1.4","1.6","0.6","3.6" "2002","1.3","1.5","0.6","3.4" "2003","1.3","1.5","0.6","3.4" "2004","1.2","1.5","0.6","3.3" "2005","1.1","1.5","0.6","3.2" "2006","0.9","1.4","0.6","2.8" "2007","0.9","1.3","0.5","2.7" "2008","0.7","1.2","0.5","2.4" "2009","0.6","1.0","0.5","2.1" "2010","0.6","1.0","0.5","2.1" "2011","0.5","1.0","0.5","2.1" "2012","0.5","1.0","0.5","2.0"