Crystalline Silica and RSP Control Methods Effectiveness during Concrete Grinding

描述（由申请人提供）：混凝土表面研磨在建筑行业中产生最高水平的结晶二氧化硅粉尘之一，使混凝土研磨机暴露于与各种呼吸道疾病和其他疾病相关的这种剧毒化学品的不可接受水平。这项拟议的研究是我们最近完成的试点项目的后续行动，该项目由国家职业安全与健康研究所（NIOSH）通过保护工人权利中心资助，涵盖了多个NIOSH诺拉优先领域：干预有效性研究、慢性肺部疾病、控制技术和暴露评估。本研究的长期目标是表征/预防施工活动期间的二氧化硅粉尘暴露。其短期目标是确定其他可用粉尘控制方法的可行性、局限性和有效性，以增强混凝土研磨过程中现有的粉尘控制方法。我们的初步研究证实了以前的研究结果，包括我们在2002年的研究，即常用的方法不能将二氧化硅粉尘减少到可接受的水平。拟议的研究将展示主要相关影响因素的影响，并将揭示有效控制二氧化硅粉尘的这些因素的组合。本研究将在受控环境（现场实验室）中进行，以收集数据。硅石粉尘取样参数（因素）如下：（a）研磨技术：不受控制1（常规研磨），受控2（湿式研磨和通风研磨）;（B）研磨机直径尺寸：3（4.5 吋、7 吋及9 吋）;（c）一般通风位置：2（开、关）;（d）取样时间设定：3（常规磨5、15、25 min，湿磨30、45、60 min，通风磨45、60、90 min）;（e）控制方法流量：常规研磨1（0，无水或气流）、湿研磨水流量3 [0.2、0.4、0.8L/min/英寸直径]和通风研磨气流速率3（0.25、0.50、1.0L/min/英寸直径）。因此，（1 x 3 x 2 x 3 x 1）析因设计适用于不受控的常规研磨，（2 x 3 x 2 x 3 x 3）析因设计适用于湿研磨和通风研磨。在每个因子水平下，将采集2份个人样本（重复），并将其平均值报告为该因子水平的二氧化硅浓度。空气样本总数将为252个。对于质量控制，还将采集28份空白样品、30份背景样品和20份原液样品。将使用多重方差分析来分析数据，以找到所需的因素组合。

DESCRIPTION (provided by applicant): Concrete surface grinding generates one of the highest levels of crystalline silica dust in the construction industry, exposing concrete grinders to unacceptable levels of this highly toxic chemical linked to a variety of respiratory and other diseases. The proposed study, a follow up of our recently completed pilot project funded by the National Institute for Occupational Safety and Health (NIOSH) through the Center to Protect Workers' Rights, covers multiple NIOSH NORA priority areas: intervention effectiveness research, chronic pulmonary diseases, control technology and exposure assessment. This study's long-term goal is to characterize/prevent silica dust exposure during construction activities. It's short-term goal is to determine the feasibility, limitations and effectiveness of additional available dust control methods in enhancing existing dust control methods during concrete grinding. Our pilot study confirmed previous studies' findings, including our study in 2002, that the commonly used approaches do not reduce silica dust to acceptable levels. The proposed study will demonstrate the effects of major relevant influencing factors and will reveal the combinations of those factors that effectively control silica dust. The study will be performed in a controlled environment (a field laboratory) to collect data. Silica dust sampling parameters (factors) will be as follows: (a) grinding techniques: uncontrolled 1 (conventional-grinding), controlled 2 (wet-grinding and ventilated- grinding); (b) grinder diameter sizes: 3 (4.5-inch, 7-inch and 9-inch); (c) general ventilation position: 2 (on, off); (d) sampling time set up: 3 (conventional- grinding 5,15, 25 min, wet-grinding 30, 45, 60 min, ventilated- grinding 45, 60, 90 min); (e) control method flow-rate: conventional-grinding 1 (0, no water or airflow), wet- grinding water flow 3 [0.2, 0.4, 0.8 L/min/inch diameter], and ventilated-grinding airflow-rate 3 (0.25, 0.50, 1.0 L/min/inch diameter). Thus, the (1 x 3 x 2 x 3 x 1) factorial design applies to uncontrolled conventional- grinding and the (2 x 3 x 2 x 3 x 3) factorial design applies to wet-grinding and ventilated-grinding. At each factor level, 2 personal samples (replicate) will be collected and their average value will be reported as the silica concentration for that factor level. The total resulting number of air samples will be 252. For quality control, 28 blank, 30 background and 20 bulk samples will also be collected. Multiple analyses of variance will be used to analyze the data to find the desired combination of factors.