A　sea　breeze　is　a　local　circulation　that　occurs　in　coastal　regions　from　the　poles　to　the　equator.　The　adverse　influence　of　ship　emissions　on　air　quality　in　coastal　areas　may　be　aggravated　by　the　onshore　flow　of　sea　breeze　circulation.　However,　our　knowledge　regarding　the　evolution　of　ship-emitted　pollutants　during　a　specific　sea　breeze　episode　is　still　limited.　To　address　this　knowledge　gap,　this　study　investigated　the　evolution　of　ship　emissions　during　a　sea　breeze　episode　that　occurred　on　29　June,　2014　in　Tangshan　port　in　China　by　employing　the　WRF/Chem　model.　NO2,　one　of　the　primary　pollutants　emitted　by　ships,　was　selected　as　the　target　pollutant　for　investigation.　The　results　indicate　that　the　ground　level　NO2　concentration　was　considerably　affected　by　sea　breeze　circulation.　Although　the　onset　of　the　sea　breeze　was　delayed　until　nearly　midday　due　to　offshore　synoptic　winds,　ship-emitted　NO2　was　transported　to　more　than　100　km　inland　with　the　penetration　of　the　sea　breeze.　Further　investigation　found　that　the　averaged　concentration　of　ship-contributed　NO2　during　the　episode　showed　an　evident　downward　trend　as　the　distance　from　the　coastline　increased.　Vertically,　the　shallow　atmospheric　boundary　layer　(ABL)　on　the　sea　limited　the　vertical　dispersion　of　ship　emissions,　and　the　pollutant　was　transported　shoreward　by　the　sea　breeze　within　this　shallow　ABL.　The　height　of　the　ABLs　is　lowered　in　coastal　regions　due　to　the　cooling　effect　of　sea　breezes　which　brings　the　cool　marine　air　to　the　hot　land　surface.　Ship-contributed　NO2　was　mostly　trapped　in　the　shallow　ABL;　thereby,　its　concentration　increased.