粉尘采样几项影响因素的比较研究

Comparative study of aerosol sampling among influence factors

目的研究影响工作场所空气中粉尘采样的因素及其方法的局限性,从而改善采样方法。方法通过对造船厂电焊烟尘的现场采样及其他厂矿矿物粉尘采样数据的分析,比较性地研究空白样本、去静电称量、样本增重以及检出限(limit of detection,LOD)等项因素,强调它们对最终结果的影响。结果经现场空白校正,电焊烟尘样本浓度大多明显降低,变化范围为9.3%^-24.3%。相比之下,去静电影响较小,变化范围为1.0%^-2.1%。实验室空白校正使得样本浓度降低和升高各半,无明显变化趋势。厂矿269例美国呼尘样本最低检出限(LOD)符合率为17.3%,造船厂常规流量旋风器FSP2采集的呼尘其LOD符合率仅为12.2%。而在同一地点大流量旋风器FSP10采集的呼尘其LOD符合率升高至73.9%。粉尘浓度测定值在不同厂矿多呈正偏态分布。结论与静电效应和实验室空白相比,现场空白对最终结果的影响更大。LOD符合率过低,影响粉尘采样的可靠性,这可通过使用大流量采样器来改善。还讨论了数据分布及其合适的统计方法。

Objective To investigate the influence factors and methodological limitations of workplace aerosol sampling,in order to improve the sampling methods.Methods Through applying data from a field sampling in two shipyards and analyzing a large dust data from different industries,the influence factors such as blank setting,electrostatic effect,sample mass gain,limit of detection（LOD）were comparatively studied with emphasis on their effect to the final result.Results The present results showed that the filed blank calibration was the predominant factor which resulted in significant decrease in the welding fume concentration with variation until to-24.3%,in comparison to electrostatic effect（with a variation from 1.0% to-2.1%）and the laboratory blank（no definite change tendency）.The coincidence rate with LOD was only17.3%for American respirable dust from 269 samples in different industries and 12.2%for respirable fumes by normal flow cyclone FSP2 in the shipyard,the late increased to 73.9% by using high flow sampler of FSP10.Furthermore,the data on most concentration from the different industries were in positive skewed distribution,with only few exceptions.Conclusions It was suggested that filed blank calibration was the predominant factor,in comparison to electrostatic effect and the laboratory blank.The LOD coincidence rate was too low to be a reliable sampling methods,and might be improved by use of high flow samplers.