The　measurement　of　PM2.5　was　conducted　from　15(th)　August　to　17(th)　September,　2015　in　Shijiazhuang,　China,　covering　the　period　of　a　ceremonial　parade.　The　PM2.5　concentrations　and　the　major　chemical　components　were　analyzed.　The　concentrations　of　PM2.5　was　26.5　mu　g　m(-3)　during　control,　which　were　57.0%　and　51.1%　lower　compared　to　before　and　after　control,　respectively.　The　lowest　concentrations　of　elements　and　water-soluble　ions　were　also　found　during　control　with　a　decreasing　tread　of　31.1%-44.2%,　and　57.1%-64.2%,　respectively.　Two　typical　pollution　episodes　characterized　by　significantly　elevated　PM2.5　concentration　were　found　during　no　control　due　to　the　combination　of　no　emission-reduction　measures　and　unfavorable　weather　conditions.　The　mass　percentage　of　secondary　inorganic　ions　was　larger　during　no　control　(　38.1%-40.3%),　pointing　to　the　strong　contribution　of　atmospheric　chemical　processes.　The　NO3-/SO42-　ratios　were　0.85,　0.94,　and　0.85　before,　during,　and　after　control,　respectively,　and　the　elevated　ratios　during　control　indicate　a　greater　proportion　of　the　PM2.5　originated　from　vehicle　exhaust.　The　WRF-CMAQ　modeling　system　was　also　used　to　assess　the　effectively　of　emission　reduction　measures　and　weather　conditions.　The　results　indicated　that　the　PM2.5　concentration　increased　by　21.6%　and　32.1%　if　no　emission-reduction　measures　were　taken　and　weather　conditions　in　2014　were　used.