Bioaerosols　released　from　municipal　wastewater　treatment　plants　(MWWTPs)　contain　pathogenic　microorganisms,　if　dispersed　into　the　atmosphere,　which　pose　potential　health　risks　to　humans.　In　this　study,　the　concentrations　and　size　distribution　of　bioaerosol,　factors　on　the　bioaerosol　emission,　exposure　risk,　and　microbial　composition　in　different　treatment　units　of　a　MWWTP　were　investigated.　The　results　showed　that　bioaerosol　was　released　to　different　degrees　in　each　treatment　unit,　with　the　concentrations　of　bioaerosol　varied　widely,　ranging　from　978　to　3710　CFU/m3.　FG　and　PST　were　primary　bioaerosol　emission　sources　in　MWWTP.　COD　concentration,　wind　speed　(WS)　and　relative　humidity　(RH)　significantly　influenced　bioaerosol　concentrations.　The　proportion　of　inhalable　particles　(＜　4.7　μm)　ranged　from　51.35　%　to　83.33　%,　and　bioaerosol　emitted　from　WWTP　caused　a　non-carcinogenic　risk　to　children　by　the　exposure　risk　assessment　(HI　＞　1),　which　need　to　be　paid　more　attention.　Bacterial,　fungal　and　actinomycete　aerosols　were　detected　in　each　treatment　unit　of　MWWTP.　Among　these　bioaerosols,　bacterial　aerosol　was　dominant.　Importantly,　several　pathogenic　bacteria　including　Sphingobium,　Brevundimonas,　Romboutsia,　Arcobacter,　Acinetobacter,　and　Mycobacterium　were　identified　within　the　airborne　bacteria　population,　most　of　which　originated　from　wastewater　or　sludge,　particularly　in　the　ambient　air　of　AeT.　Pathogenic　bacteria　from　MWWTP　should　be　studied　further　to　determine　their　long-term　behavior　and　possible　health　risks.　©　2024　Elsevier　B.V.