In　this　study,　the　24-h　PM2.5　(i.e.,　the　fine　particles　with　aerodynamic　diameter　of　＜=　2.5　mu　m)　samples　were　collected　at　two　different　functional　subdivisions　in　the　city　of　Tangshan　during　the　period　of　July　2012　to　April　2013.　The　months　of　July,　October,　January,　and　April　were　chosen　to　represent　four　different　typical　seasons.　The　total　PM2.5　mass　was　measured.　PM2.5　samples　were　used　for　the　analysis　of　inorganic　elements,　ions,　Organic　Carbon　(OC)　and　Elemental　Carbon　(EC).　PM2.5　concentration　in　the　industrial　subdivision　were　generally　higher　than　those　in　the　residential　subdivision.　The　annual　mean　PM2.5　concentrations　were　196　mu　g　m(-3)　for　the　industrial　subdivision　and　116　mu　g　m(-3)　for　the　residential　subdivision.　The　coefficients　of　divergence　(CD)　calculated　for　spring,　summer,　autumn　and　winter　were　0.67,　0.35,　0.65,　and　0.33,　respectively.　The　Enrichment　Factor　Method　(EFM)　was　used　to　help　determine　the　original　sources　of　these　inorganic　elements.　Secondary　water-soluble　ions　(SO42-,　NO3-,　and　NH4+)　were　the　major　water　soluble　ions　in　the　PM2.5　of　Tangshan,　and　they　are　present　in　the　atmosphere　as　(NH4)(2)SO4　and　NH4NO3.　The　Sulfur　Oxidation　Ratio　(SOR)　and　Nitrogen　Oxidation　Ratio　(NOR)　show　that　the　precursor　conversion　ratio　was　highest　in　summer.　At　both　subdivisions,　winter　had　the　highest　monthly　average　OM　concentration　while　summer　had　the　lowest.