PM2.5　air　pollution　in　metropolises　as　well　as　some　medium-sized　cities　in　the　North　China　Plain　have　aroused　many　researchers＇　interest,　but　less　attention　has　been　paid　to　the　rural　areas　of　this　region.　In　this　study,　four　months　of　daily　PM2.5　samples　were　collected　from　a　rural　site　in　Lingcheng　(a　district　of　Dezhou　City　in　Shandong　Province)　during　different　seasons　in　2013　and　2014.　Analysis　of　the　samples　indicates　that　the　PM2.5　air　pollution　was　severe　over　this　area　with　the　four-month　average　concentration　of　105.9　mu　g/m(3),　three　times　higher　than　China＇s　guideline　for　this　pollutant　(35　mu　g/m(3)).　In　winter,　the　monthly　average　concentration　was　as　high　as　1512　mu　g/m(3).　In　order　to　identify　the　potential　source　regions,　the　Integrated　Source　Apportionment　Method　within　Community　Multiscale　Air　Quality　model　(CMAQ-ISAM)　was　applied　during　the　wintertime.　The　regional　source　apportionment　results　show　that　local　emissions　in　Lingcheng　only　contributed　15.4%　to　PM2.5　concentrations,　with　12.6%　and　28.1%　from　its　circumjacent　areas　in　Dezhou　City　and　the　six　surrounding　cities,　respectively.　Regional　transport　from　areas　farther　away　and　the　boundaries　account　for　31.6%　and　11.1%,　respectively.　This　indicates　that　the　ambient　PM2.5　at　Lingcheng　is　not　affected　only　by　emissions　from　local　and　circumjacent　areas;　regional　and　long-range　transport　should　also　be　considered.　Further　analysis　indicated　that　with　increasing　degrees　of　pollution,　the　contributions　from　local　and　circumjacent　regions　showed　a　clear　downward　trend,　while　the　contributions　from　northern　and　southwestern　areas,　which　most　of　the　trajectories　passed　through　during　periods　of　heavy　haze,　showed　an　obvious　upward　trend.　(C)　2017　Elsevier　B.V.　All　rights　reserved.