道路扬尘评估方法的建立和比较

建立了降尘法和AP-42法2种道路扬尘评估方法，它们分别以减去背景降尘的道路自身降尘（ΔDFr）和道路扬尘排放强度（EIr）作为评估指标. 通过对这2种方法评估结果的比较与分析发现:①ΔDFr和EIr有很好的正相关关系，相关系数（R2）为0.708；②ΔDFr能同时反映车辆激发扬尘和路面风蚀扬尘，而EIr只反映车辆激发扬尘；③积尘负荷大小不代表评估道路扬尘污染程度，但适用于定量评价道路清扫保洁质量. 降尘法相比AP-42法，其实施安全、简单易行、误差小，但不能满足快速评估要求，而且评估成本略高. 2种评估方法均表明《奥运保障措施》控制道路扬尘的效果明显，2008年北京奥运会期间与2007年同期相比，快速路、主干路、次干路和支路ΔDFr分别下降了65%，55%，65%和84%. 

Establishment and Comparison of Evaluation Methods for Fugitive Road Dust

In this article,we set up two methods for evaluation of fugitive road dust: the dust fall method and the AP-42 method.The two methods use relative road dust fall after subtracting background dust fall(ΔDFr) and the emission intensity of fugitive road dust(EIr) as the evaluation indices.Three conclusions have been drawn through comparing evaluation results of these two methods.First,ΔDFr and EIr are positively correlated,with a correlation coefficient R2 of 0.708.Second,ΔDFr can simultaneously measure the fugitive dust generated by vehicles and wind erosion of the road surface silt,while EIr can only measure fugitive dust generated by vehicles.Third,the single index of silt loading(sL) does not reflect the degree of pollution from fugitive road dust,but can be applied to quantitatively evaluate the quality of city road sweeping and cleaning.Compared with the AP-42 method,the dust fall method is safer and easier to use with only small errors,but it does not provide fast results and has slightly higher costs.The two methods both indicate that the policies of Guaranteeing Measures of the 2008 Olympic Games had an obvious effect on controlling fugitive road dust.Comparing the period of the 2008 Olympic Games with the same period in 2007 shows that ΔDFr on freeways,major arterial,minor arterial and collector roads was reduced by 65%,55%,65% and 84%,respectively.