Electronic　cigarettes　(E-cigarettes)　have　gained　significant　popularity　in　recent　years　as　a　substitute　for　combustible　cigarettes.　However,　there　is　growing　concern　regarding　the　safety　of　E-cigarette　products　for　both　the　users　and　those　exposed　passively　to　second-hand　emissions,　which　contain　nicotine　and　other　toxic　substances.　In　particular,　the　characteristics　of　second-hand　PM1　exposure　and　the　transmission　of　nicotine　from　E-cigarettes　remain　unclear.　In　this　study,　the　untrapped　mainstream　aerosols　from　the　E-cigarette　and　smoke　from　cigarettes　were　exhausted　by　the　smoking　machines　which　were　operated　under　standardized　puffing　regimes　to　simulate　second-hand　vapor　or　smoke　exposure.　The　concentrations　and　components　of　PM1　released　from　cigarettes　and　E-cigarettes　were　compared　under　varying　environmental　conditions　and　regulated　using　a　heating,　ventilation,　and　air　conditioning　(HVAC)　system.　Additionally,　the　ambient　nicotine　concentrations　and　the　size　distribution　of　the　generated　aerosols　were　determined　at　different　distances　from　the　release　source.　Results　showed　that　PM1　accounted　for　the　highest　proportion　(98　%)　of　the　released　particulate　matter　(PM1,　PM2.5,　and　PM10).　The　mass　median　aerodynamic　diameter　(MMAD)　of　cigarette　smoke　(0.5　&　PLUSMN;　0.01　&　mu;m,　geometric　standard　deviation　(GSD)　1.97　&　PLUSMN;　0.1)　was　smaller　than　that　of　E-cigarette　aerosols　(1.06　&　PLUSMN;　0.14　&　mu;m,　GSD　1.79　&　PLUSMN;　0.19).　The　PM1　concentrations　and　chemical　components　were　effectively　reduced　when　the　HVAC　system　was　utilized.　Nicotine　concentrations　in　E-cigarette　aerosols　were　comparable　to　those　of　combustible　cigarette　emissions　when　close　to　the　exposure　source　(0　m),　while　they　declined　more　rapidly　than　cigarette　smoke　emissions　with　increasing　distance　from　the　source.　Furthermore,　the　maximum　nicotine　concentrations　occurred　in　1　&　mu;m　and　0.5　&　mu;m　particles　in　E-cigarette　and　cigarette　emissions,　respectively.　These　results　provide　a　scientific　basis　for　the　assessment　of　E-cigarette　and　cigarette　aerosol　passive　exposure　risks,　guiding　the　development　of　environmental　and　human　health　control　measures　for　these　products.