Year	PM2.5	PM10	O3	NO2
2000		30.5	17.7	21.4
2001		27.9	30.0	18.4
2002		29.1	19.2	20.9
2003		41.3	58.2	27.2
2004		25.5	20.2	19.7
2005		32.8	23.6	20.3
2006	13.4	38.2	45.2	17.7
2007	4.2	28.4	21.0	19.4
2008	7.5	22.9	15.4	11.8
2009	7.4	23.9	15.0	14.9
2010	9.6	24.9	16.7	13.1
2011	13.9	30.2	14.7	11.9
2012	11.0	21.5	14.2	8.0