A　study　was　conducted　on　aerosol-radiation　interactions　over　six　cities　in　this　region　within　the　2015–2019　period.　WRF-Chem　simulations　on　2017　showed　that　based　on　the　six-city　average,　the　aerosol　load　(PM2.5　concentrations)　of　121.9,　49.6,　43.3,　and　66.3　µg/m3　in　January,　April,　July,　and　October,　mainly　lowered　the　level　of　downward　shortwave　radiation　by　38.9,　24.0,　59.1,　and　24.4　W/m2　and　reduced　the　boundary　layer　height　by　79.9,　40.8,　87.4,　and　31.0　m,　via　scattering　and　absorbing　solar　radiation.　The　sensitivity　of　meteorological　changes　to　identical　aerosol　loads　varied　in　the　order　July　＞　January　＞　October　and　April.　Then,　the　cooling　and　stabilizing　effects　of　aerosols　further　led　to　increases　in　PM2.5,　by　23.0,　3.4,　4.6,　and　7.3　µg/m3　respectively　in　the　four　months.　The　sensitivity　of　the　effect　of　aerosols　on　PM2.5　was　greatest　in　January　rather　than　in　July,　contrary　to　the　effect　on　meteorology.　Moreover,　a　negative　linear　relation　was　observed　between　daily　BLH　reductions　and　aerosol　loads　in　fall　and　winter,　and　between　PM2.5　increases　and　aerosol　loads　in　all　seasons.　With　the　PM2.5　pollution　improvements　in　this　region,　the　aerosol　radiative　forcing　was　effectively　reduced.　This　should　result　in　daily　BLH　increases　of　10–24　m　in　fall　and　winter,　and　the　estimates　in　Beijing　agreed　well　with　the　corresponding　results　based　on　AMDAR　data.　Additionally,　the　reduction　in　aerosol　radiation　effects　brought　about　daily　PM2.5　decreases　of　1.6-2.8　µg/m3,　accounting　for　7.0%–17.7%　in　PM2.5　improvements.　©　2022