Quantitative effect evaluation on dust control measures of construction sites

With the urban planning and construction, large-scale construction projects have produced amounts of atmospheric pollutants represented by coarse particulate matter (PM₁₀) in the process of foundation excavation, main construction and exterior wall decoration. In order to minimize PM₁₀ caused by dust at construction sites, relevant departments require to take dust suppression measures at construction sites such as bare soil covering, stereoscopic spraying and enclosure isolation. The dust suppression effect of each measure was explored based on the on-site dust suppression measure controlled experiments and high-precision numerical wind tunnel experiments. The results showed that PM₁₀ concentration decreased by 5.1% when only using enclosure spraying, the concentration decreased by 12.3% when only using construction spraying, and when both measures were used, the concentration decreased by 11.4%. When the wind speed was high, the dust suppression effect of bare soil cover was more significant than that of low wind, and the mean PM₁₀ concentration of bare soil cover under third-level wind (>2 m/s) was 10.7% lower than that without bare soil cover. PM₁₀ concentration of bare soil spray decreased by 21.3% compared with that of no spray. On the whole, the dust reduction rates during the foundation excavation stage were 3.6%, 10.5%, 18.4% and 29.0% for enclosure heights of 2, 3, 4 and 5 m, respectively. In the main construction stage, the influence distance of dust diffusion gradually decreased with the increase of emission source. When the source height was 10 m, the maximum influence distance was 75 m outside the construction site; when the source height was 30m, the maximum influence distance was 50 m. When the source height was 50 and 90 m, the dust dissipation rate was less than 10% as soon as the dust source left the site, which means that the impact outside the site could be ignored.