The　emergency　response　to　the　COVID-19　pandemic　had　an　extreme　exogenous　impact　on　society　and　the　economy.　This　paper　aims　to　explore　the　impacts　of　the　national　emergency　response　and　the　subsequent　emergency　response　termination　on　air　quality　and　its　policy　implications　through　regression　discontinuity　design　(RDD)　estimation　by　employing　panel　data　on　daily　air　quality　from　January　1,　2019,　to　July　31,　2020,　for　290　cities　in　China.　The　empirical　results　showed　that　the　emergency　response　resulted　in　a　significant　decrease　in　most　of　the　major　pollutant　concentrations　within　a　short　time　frame,　and　the　average　air　quality　index　(AQI)　decreased　by　approximately　11.0%.　The　concentrations　of　PM2.5,　PM10,　SO2,　NO2,　and　CO　decreased　by　approximately　18.8%,　13.1%,　13.5%,　11.1%　and　6.7%,　respectively,　while　the　O3　concentration　did　not　change　significantly.　Further　causal　analysis　found　that　mandatory　traffic　restrictions　and　the　shutdown　of　industries　were　two　important　factors　that　contributed　greatly　to　air　quality　improvement.　Moreover,　since　the　process　of　returning　to　normal　daily　activities　and　promoting　the　economy　were　gradual,　the　results　showed　that　air　pollution　did　not　rebound　immediately　after　the　government　called　for　the　“resumption　of　production　and　work”　and　announced　the　“termination　of　the　emergency　response”.　Our　findings　suggest　that　to　achieve　a　substantial　and　sustainable　improvement　in　air　quality,　it　is　necessary　to　continuously　implement　strict　emission　control　routines　and　take　co-control　measures　for　various　VOCs　precursors　of　ozone.　©　2023　Elsevier　Ltd