China　has　been　experiencing　and　suffering　in　a　serious　air　pollution　problem　these　years　and　has　brought　air　quality　into　spotlight.　Air　pollution　is　a　key　factor　of　indoor　air　quality　and　has　a　considerable　impact　on　the　public　health　and　indoor　occupants’　activities.　China　still　adopts　air　quality　index　(AQI)　and　primary　pollutant　for　assessing　the　degree　of　air　pollution,　which　ignore　the　effects　of　non-primary　pollutants　during　the　same　period　and　the　dynamic　characteristics　of　all　pollutants.　In　order　to　consider　the　comprehensive　impact　of　various　pollutants　on　air　quality,　the　total　air　quality　index　(TAQI)　is　proposed　as　an　indicator　to　measure　the　total　air　quality.　A　new　index,　contribution　rate　(IAQIP/TAQI),　is　further　proposed　as　the　contribution　of　a　pollutant　to　total　air　quality,　which　may　be　much　different　from　the　chief　pollutant.　In　this　study,　the　daily　average　values　of　six　pollutants’　concentrations　in　thirty-one　provincial　capital　nationwide　from　2014　to　2017　are　used　as　data　sources.　According　to　these　indexes,　the　dynamic　characteristic　of　local　air　pollutant　composition　is　studied　and　explored.　The　indexes　proposed　in　this　study　have　a　guiding　significance　for　improving　air　quality　evaluation　and　help　create　better　indoor　air　environment　in　different　regions.　©　2020,　Springer　Nature　Singapore　Pte　Ltd.