北京市混凝土搅拌站风蚀扬尘排放特征

Emission Characteristics of Wind-Eroded Dust from Concrete Batching Plants in Beijing

混凝土搅拌站是北京市一类典型扬尘源,本研究以北京市2座混凝土搅拌站为例,采用美国沙漠所的便携式风洞(PISWERL)测试搅拌站料堆和道路风蚀扬尘排放特征,结合搅拌站料堆和道路表面扰动频次以及当地气象数据,建立搅拌站料堆和道路风蚀扬尘PM_(2.5)本地化排放因子.结果表明:(1)搅拌站骨料大棚进口、混凝土装载区、社会道路进口和搅拌站进口道路风蚀扬尘PM_(2.5)日均排放因子差异不明显,分别为0.45、0.41、0.31和0.30 kg·(hm^2·d)^(-1),降水对道路风蚀扬尘PM_(2.5)年排放因子的削减率仅为4%;(2)搅拌站粗石、细石、粗砂和细砂料堆风蚀扬尘PM_(2.5)日均排放因子分别为0.10、0.12、0.26和2.02 kg·(hm^2·d)^(-1),细砂料堆风蚀扬尘排放因子是粗石、细石和粗砂料堆的20.5、16.8和7.7倍,细砂料堆春季排放因子是夏秋冬季的6.4、3.4和1.3倍;(3)北京市搅拌站料堆和道路风蚀扬尘PM_(2.5)日均排放因子分别为1.13 kg·(hm^2·d)^(-1)和0.37 kg·(hm^2·d)^(-1),是AP-42文件(c11s12混凝土,1995年版)料堆风蚀扬尘排放因子推荐值的3.9和1.3倍,搅拌站风蚀扬尘排放因子的不确定性范围为34%~92%;(4)建议搅拌站加强道路洒水和清扫保洁,对料堆尤其细砂料堆实施全封闭储存和喷雾降尘.

Concrete batching plants are a typical source of fugitive dust in Beijing. In this study,two concrete batching plants in Beijing were used to test wind erosion of dust with a Portable In-suit Wind Erosion Laboratory（PI-SWERL） designed by the Desert Research Institute（DRI）. Sand and aggregate storage piles and paved roads in concrete batching plants were tested to determine the emission characteristics of wind eroded dust. Combining the frequencies of disturbance of storage piles and paved road surface with local meteorological data,localized wind erosion dust emission factors of PM_（2.5） were established. Results demonstrate that：（1）There are small differences in daily average emission factors for PM_（2.5） between the aggregate warehouse entrance area,concrete loading area,social road import area,and concrete batching plant entrance area,with these being 0. 45,0. 41,0. 31,and 0. 30 kg·（hm^2·d）^-1respectively.（2）Daily average emission factors for PM_（2.5） of coarse stone,fine stone,coarse sand,and fine sand storage piles are 0. 10,0. 12,0. 26,and 2. 02 kg·（hm^2·d）^-1respectively. Emission factors of fine sand storage piles are 20. 5,16. 8,and 7. 7 times greater than those of coarse stone,fine stone,and coarse sand,respectively,and spring emission factors are 6. 4,3. 4,and 1. 3 times greater than those of summer,autumn,and winter,respectively.（3）Daily average emission factors for PM_（2.5） of storage piles and paved roads are 1. 13 and 0. 37 kg·（hm^2·d）^-1respectively 3. 9 and 1. 3 times higher than the wind erosion factor from storage piles from AP-42 files（c11 s12 concrete batching,1995）; the uncertainty range of the emission factor is 34%-92%.（4） It is recommended to strengthen watering,sweeping,and cleaning of paved roads,and to ensure fully enclosed storage and use of spray water to reduce wind erosion of dust from storage piles,especially from fine sand piles.