Abstract: Leaves of plants have a great effect on the removal of atmospheric particulate matter (PM). Likewise, the barks of plants have the similar function. In addition, previous research has already proved that particles deposited on the bark surface have a relatively slight influence on biological regulating function. This study investigated the adsorption capacity of barks of ten common plant species in Beijing. The PM adsorption mass per unit area of each species’ bark in different seasons was measured. Three fractions of PM were thus collected: 10-100 μm (large), 2.5-10 μm (coarse) and 0.2-2.5 μm (fine). Furthermore, the barks were classified according to adsorption capacity. The results showed that barks generally had great adsorption capacity of particulate matter with an average of 2182.07 μg·cm^-2. The mass of large particles accounted for 88% of the total, and the fine particles and coarse particles accounted for 6% respectively. The mass of large particles deposited on the barks changed significantly under different meteorological and pollution conditions, while the mass of small particles did not. In general, bark’s adsorption mass was high in the season with heavy haze and less rain or wind. However, adsorption mass was low in the windy and rainy season. For particles deposited on the bark, some of them would be suspended once again, some of them would be removed by rainfall, and the rest would continue to accumulate on the bark surface. In the same particle size range, bark’s adsorption capacity of particulate matter differed with species, affected by the surface structure and properties of the bark. They were divided into four categories: (1) rough bark with strong adsorption ability and low moisture and lipid; (2) smooth bark with weak adsorption capacity and high moisture and lipid; (3) bark with medium adsorption capacity and shallow or longitudinal crack; (4) split bark with differential adsorption capacity of different sized particles. This study proved the effect of bark on removing atmospheric particulate matter and provided theoretical foundation for urban green space planning system, which would decrease human exposure to atmospheric pollutants in the future.

Key words: yield, summer maize, nitrate nitrogen, winter wheat, nitrogen balance.