Analysis of the Effect of Vegetation Types in Industrial Heat Source Radiation Areas on PM2.5 Concentration Reduction in the Beijing–Tianjin–Hebei Region

Industrial heat source (IHS) radiation areas are key accumulation zones for fine particulate matter with an aerodynamic diameter of 2.5 μm or less (PM2.5) in heavily industrialized regions, but PM2.5 concentration reduction rates by vegetation types have not been systematically assessed. A systematic analysis of PM2.5 concentration reduction rates by vegetation types using IHS, PM2.5, land-cover, and digital elevation model (DEM) data was conducted to assess PM2.5 concentration reduction rates by vegetation types within IHS radiation areas. First, this study adopted the published IHS radiation-area dataset developed by Xin Sui et al. to define the spatial extent of industrially influenced areas. Second, PM2.5 concentrations were extracted within IHS radiation areas and areas covered by different vegetation types to support the calculation of PM2.5 concentration reduction rates. Third, PM2.5 concentration reduction rates by vegetation types were evaluated through masking and regional statistical analysis. Results for Beijing–Tianjin–Hebei (BTH) in 2015 and 2020 show that: (1) the average PM2.5 decreased from 71.70 to 39.60 µg/m3, corresponding to an overall reduction of 44.8%; (2) PM2.5 concentration reduction rates varied substantially among vegetation types; open deciduous broadleaved forest showed the highest reduction rate of 39.08%, while rainfed and irrigated cropland showed negative reduction rates of −9.35% and −6.71%; (3) city-scale and case analyses show denser vegetation in radiation zones generally lowers PM2.5 even under ongoing industrial activity. The study supports vegetation greening, IHS control, regional air quality improvement, and sustainable industrial development strategies.