Windbreak efficiency in controlling wind erosion and particulate matter concentrations from farmlands

•Windbreaks can effectively reduce wind erosion on agricultural fields by 20 %.•Windbreaks can attenuate the spike of PM concentrations.•The dispersion of PM10 to downwind areas could be reduced by windbreaks.•Windbreak have little impacts on dispersion of PM2.5 and PM1 concentrations. Particulate matter (PM) emissions from farmlands due to wind erosion have resulted in serious land degradation, air pollution, and human health problems. Although windbreaks have been traditionally planted on farmlands to reduce soil erosion, only a few studies examining wind erosion and PM emissions on farmlands utilizing windbreaks have been undertaken. In our study, the performance of windbreak patches and strips used for mitigating wind erosion and PM pollution were examined in-situ between 2017 and 2019. Soil loss and PM emissions from farmlands with and without windbreaks were measured using sediment traps, dust monitors and samplers during high wind events in a non-foliage period. Results indicated that soil loss in windbreak patches was 20 % lower than that on farmlands; compared to farmland, windbreak patches resulted in wind speed reductions of 27 % and 30 % at heights of 0.2 m and 2 m, respectively. The use of windbreak strips resulted in a reduction of PM10 dispersion in downwind areas, recording a steeper decline of PM10 concentrations in the open transect than in the vegetated transect. For PM2.5 and PM1, the rate of decline was similar between the two transects. Windbreak strips were also recorded to reduce vertical PM10 flux, with average values of 0.68 and -2.81 μg m−2 s-1 on the windward and leeward side, respectively. Shelter effects of windbreaks were highest when windbreak porosities were between 40 %–60 %, during which the shelter distance was between 7–9 times tree height. Results from this study can be used to assess wind erosion and PM emissions from farmlands with windbreaks, enabling suitable positioning of the windbreaks to maximize their effects.