Jørgensen Rikke Bramming, Kero Ida Teresia, Blom Aleksander, Grove Esten Eide, Svendsen Kristin von Hirsch
Department of Industrial Economics and Technology Management, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
Department of Materials Production and Processing, SINTEF Industry, P.O. Box. 4760, NO-7465 Trondheim, Norway.
Nanomaterials (Basel). 2020 Dec 17;10(12):2546. doi: 10.3390/nano10122546.
It is difficult to assess workers' exposure to ultrafine particles (UFP) due to the lack of personal sampling equipment available for this particle fraction. The logbook method has been proposed as a general method for exposure assessment. This method measures the time and concentration components of the time-weighted average concentration separately and could be suitable for investigation of UFP exposure.
In this study, we have assessed workers' exposure to UFP in a ferrosilicon plant. The main tasks of the furnace workers were identified, and the logbook method was used in combination with stationary measurements of UFP taken as close to the identified task areas as possible. In order to verify the results, respirable particles were collected using stationary sampling in close proximity to the UFP measuring instrument, and personal full-shift sampling of respirable particles was performed simultaneously. Thus, exposure to respirable particles determined using the logbook method could be compared to the results of standard measurement.
The particle number concentration of ultrafine particles was determined using a NanoScan SMPS. Respirable particle concentration and exposure were determined using a sampling train consisting of a pump, filter, filter cassettes, and SKC Cyclone for the respirable fraction. Attendance times for workers at each work location were registered via thorough observations made by the research team.
The logbook method for exposure estimation based on stationary sampling equipment made it possible to calculate UFP exposure for workers operating the furnaces at a ferrosilicon plant. The mid-size furnace and the large furnace were evaluated separately. The workers operating the largest furnace were exposed to 1.47 × 10 particles/cm, while workers operating the mid-size furnace were exposed to 2.06 × 10 particles/cm, with a mean of 1.74 × 10 particles/cm. Substantial contributions from the casting area, ladle transport corridor, and both tapping areas were made. Exposure to respirable particles was 2.04 mg/m (logbook); 2.26 mg/m (personal sampling) for workers operating the large-sized furnace, 3.24 mg/m (logbook); 2.44 mg/m (personal sampling) for workers operating the medium-sized furnace, and 2.57 mg/m (logbook); 2.53 mg/m(personal sampling) on average of all tappers. The average ratio of these two methods' results was 1.02, which indicates that the logbook method could be used as a substitute for personal sampling when it is not possible to perform personal sampling, at least within this industry.
The logbook method is a useful supplement for exposure assessment of UFP, able to identify the most polluted areas of the workplace and the contribution of different work tasks to the total exposure of workers, enabling companies to take action to reduce exposure.
由于缺乏适用于该粒径颗粒的个人采样设备，很难评估工人接触超细颗粒（UFP）的情况。有人提出使用日志法作为暴露评估的通用方法。该方法分别测量时间加权平均浓度的时间和浓度成分，可能适用于超细颗粒暴露的调查。
在本研究中，我们评估了硅铁厂工人接触超细颗粒的情况。确定了炉前工人的主要任务，并将日志法与在尽可能靠近已确定任务区域的位置对超细颗粒进行的固定测量相结合。为了验证结果，在靠近超细颗粒测量仪器的位置使用固定采样收集可吸入颗粒物，并同时进行可吸入颗粒物的个人全时采样。这样，就可以将使用日志法确定的可吸入颗粒物暴露情况与标准测量结果进行比较。
使用NanoScan扫描迁移率粒径谱仪（SMPS）测定超细颗粒的颗粒数浓度。使用由泵、过滤器、滤膜盒和用于可吸入部分的SKC旋风分离器组成的采样系统测定可吸入颗粒物浓度和暴露情况。研究团队通过全面观察记录工人在每个工作地点的出勤时间。
基于固定采样设备的日志法暴露评估方法，使得计算硅铁厂操作熔炉的工人的超细颗粒暴露情况成为可能。分别对中型炉和大型炉进行了评估。操作最大熔炉的工人接触到1.47×10颗粒/cm，而操作中型熔炉的工人接触到2.06×10颗粒/cm，平均为1.74×10颗粒/cm。铸造区、钢包运输走廊和两个出铁区的贡献很大。操作大型熔炉的工人可吸入颗粒物暴露为2.04mg/m（日志法）；2.26mg/m（个人采样），操作中型熔炉的工人为3.24mg/m（日志法）；2.44mg/m（个人采样），所有出铁工人平均为2.57mg/m（日志法）；2.53mg/m（个人采样）。这两种方法结果的平均比值为1.02，这表明在无法进行个人采样时，至少在该行业内，日志法可作为个人采样的替代方法。
日志法是超细颗粒暴露评估的一种有用补充方法，能够识别工作场所污染最严重的区域以及不同工作任务对工人总暴露的贡献，使公司能够采取行动减少暴露。
