工作場所奈米微粒的暴露研究

Abstract

本研究為評估不同工作場所內勞工對於PM10、PM2.5與PM 0.1微粒的暴露量，以及了解PM10、PM2.5與PM 0.1微粒濃度之間的關係，分別本研究為評估不同工作場所內勞工對於PM10、PM2.5與PM0.1微粒的暴露質量濃度，以及了解三種微粒之間的質量濃度關係，分別於鉛粉廠與鑄造廠中選取六個位置，以雙道採樣器(SA241 Dichotomous PM10/2.5 sampler, 簡稱Dichot, Thermo Fisher Sci. Inc., MA, USA.)、雷射粉塵計(TSI DustTrak, Model 8520, TSI Inc., St. Paul, MN, USA.)、慣性衝擊器(Micro-Orifice Uniform Deposit Impactor, MOUDI, Model 110, MSP Corp., St. Paul, USA)以及描瞄式電動度粒徑分析儀 (Scanning Mobility Particle Sizer, SMPS，Model 3936, TSI Inc., St. Paul, MN, USA)進行PM10、PM2.5與奈米微粒的濃度測量。將SMPS所量測到不同位置奈米微粒的數目濃度關係繪成等濃度曲線後，可得到奈米微粒的數目濃度分佈圖，從奈米微粒的數目濃度分佈圖中發現鉛粉廠中的奈米微粒數目濃度最高的地方為工作人員收集鉛粉的區域，奈米數目濃度範圍介於1.3×104 #/cm3至1.8×104 #/cm3，而整個廠區的奈米數目濃度範圍則介於7.76×103 #/cm3至4.65×104 #/cm3，平均數目濃度約為1.78×104 #/cm3，背景濃度約為5×103 #/cm3。鑄造廠中的奈米微粒數目濃度最高的地方為鐵粉回收區以及中週波融解爐融解廢鐵的區域，奈米數目濃度範圍分別介於4.6×104 #/cm3至1.04×105 #/cm3以及3.2×104 #/cm3至3.15×105 #/cm3，而整個廠區的奈米數目濃度範圍則介於2.82×104 #/cm3至3.15×105 #/cm3，平均數目濃度約為9.21×104 #/cm3，背景濃度約為1.5×104 #/cm3。 為瞭解工作場所中所發生的事件與微粒的質量濃度之間的關係性，本研究在定點使用DustTrak對於微粒的質量濃度進行長時間的及時監測，為了確認DustTrak數據的可信度，本研究以在同一時間相同地點使用Dichot所量測到的數據與DustTrak的數據進行相互比對，結果發現在鉛粉廠中"PM10,dusttrak= 2.09*PM10,dichot -6.47"(μg/m3)；"PM2.5,dusttrak= 2.56*PM2.5,dichot -12.01" (μg/m3)；在鑄造廠中"PM10,dusttrak= 1.20*PM10,dichot -6.90" (μg/m3)； "PM2.5,dusttrak= 1.66*PM2.5,dichot -35.16"，(μg/ m3)。在工作場所內的工作情況與暴露濃度息息相關，以DustTrak的測量結果發現在鉛粉廠中導致PM10與PM2.5微粒質量濃度上升的主要事件為工作人員更換鉛粉桶，瞬間最高濃度分別可達到7 mg/ m3 與4 mg/ m3，平均濃度分別約為244 μg/ m3 與171 μg/ m3，背景濃度分別約為166 μg/ m3 與110 μg/ m3。鑄造廠中導致PM10與PM2.5微粒質量濃度上升的主要事件為中週波融解爐的開啟，瞬間最高濃度分別可達到10 mg/ m3 與7 mg/ m3，平均濃度分別約為615 μg/ m3 與479μg/ m3，背景濃度分別約為84 μg/ m3 與61 μg/ m3。同時發現添加物種類對於PM10與PM2.5微粒質量濃度有著顯著的影響，在本研究所選擇的鑄造廠中對於PM10與PM2.5的質量濃度影響最大的是球化劑、其次為接種劑。 為了計算出奈米微粒的質量濃度以提供未來做為制定法規時的參考，本研究在定點放置MOUDI用以量測奈米微粒的質量濃度，並且結合SMPS與MOUDI計算出鑄造廠中奈米微粒的有效密度約為 3.0 g /cm3，再利用已知的奈米微粒有效密度搭配奈米微粒數目濃度分佈圖，可以繪出奈米微粒質量濃度分佈圖。為瞭解工作人員的質量暴露濃度，本研究在採樣的過程中利用人工的方式將工作人員的時間-活動模式加以記錄，結合此時間-活動模式以及奈米微粒質量濃度分佈圖，可以推估出工作人員的平均奈米微粒數目濃度與質量濃度暴露量，其中鑄造廠暴露濃度最高的工作人員為天車吊桶作業人員，其奈米微粒平均暴露數目濃度與暴露質量濃度分別為5.17x104 #/cm3、11.39μg /m3。

Abstract In this research, the exposure level of PM10, PM2.5 and PM0.1 mass concentrations to workers in different workplaces was assessed, and the relationship of mass concentrations between these three dust fractions was compared. Six locations in the lead powder and iron foundry plants were chosen for concentration mapping purpose. SA241 Dichotomous PM10/2.5 sampler (Dichot, Thermo Fisher Sci. Inc., MA, USA.), TSI DustTrak (Model 8520, TSI Inc., St. Paul, MN, USA.), Micro-Orifice Uniform Deposit Impactor (MOUDI, Model 110, MSP Corp., St. Paul, USA) and Scanning Mobility Particle Sizer (SMPS, Model 3936, TSI Inc., St. Paul, MN, USA) were used to measure the concentrations of PM10, PM2.5 and PM0.1. We used the nanoparticle number concentrations measured by SMPS for mapping the particle number concentrations. The highest nanoparticle number concentration in the lead powder plant was measured in the area where workers bagged the lead powder. This concentration was between 1.3×104 #/cm3 to 1.8×104 #/cm3. The nanoparticle number concentrations of the whole plant ranged between 7.76×103 #/cm3 to 4.65×104 #/cm3 with the average of about 1.78×104 #/cm3. The background nanoparticle number concentration was about 5×103 #/cm3. The highest nanoparticle number concentration in the iron foundry plant was measured in the area where the iron powder was recycled and where the iron was melted by the middle frequency furnace. The concentrations were between 4.6×104 #/cm3 to 1.04×105 #/cm3 and 3.2×104 #/cm3 to 3.15×105 #/cm3, respectively. The nanoparticle number concentrations of the whole plant ranged between 2.82×104 #/cm3 to 3.15×105 #/cm3 with the average of about 9.21×104 #/cm3. The background nanoparticle number concentration was about 1.5×104 #/cm3. In order to understand the relationship between particles mass concentrations and the work activities in the workplaces, the DustTrak was used to measure the real time particle mass concentrations during long duration in a stationary location. The Dichot was also used to measure the particle mass concentrations at the same time at the same location for comparing with the data obtained by the DustTrak. In the lead powder plant, the relationship is "PM10,dusttrak= 2.09*PM10,dichot -6.47"(μg/m3), and "PM2.5,dusttrak= 2.56*PM2.5,dichot -12.01"(μg/m3). In the iron foundry plant, the relationship is "PM10,dusttrak= 1.20*PM10,dichot -6.90" (μg/m3), and "PM2.5,dusttrak= 1.66*PM2.5,dichot -35.16"(μg/m3). In the lead powder plant, the results measured by DustTrak showed that when workers changed the barrel, the instantaneous PM10 and PM2.5 mass concentrations increased significantly to 7 mg/ m3 and 4 mg/ m3, respectively. The average concentration is 244 μg/ m3 and 171 μg/ m3, respectively, and the background concentration is 166 μg/ m3 and 110 μg/ m3, respectively. In the iron foundry plant, when the middle frequency furnace opened, the instantaneous PM10 and PM2.5 mass concentrations increased significantly to 10 mg/ m3 and 7 mg/ m3, respectively. The average concentration is 615 μg/ m3 and 479 μg/ m3, respectively, and the background concentration is 84 μg/ m3 and 61 μg/ m3, respectively. The PM10 and PM2.5 mass concentrations were found to be affected by the additives in the iron foundry plant. Nodulant affected PM10 and PM2.5 mass concentrations more than inoculant. For future regulation, nanoparticle personal exposure level was assessed in this research. The MOUDI was used to measure the nanoparticle mass concentrations in a stationary location of the iron foundry plant. Then the effective density of the nanoparticle was calculated from the SMPS and MOUDI data and found to be about 3.0 g/ cm3. The nanoparticle mass concentration mapping was made from the effective density and the number concentration mapping from the SMPS measurement. The time-activity of workers was recorded manually during sampling, and the average exposure levels of nanoparticle mass concentrations and nanoparticle number concentrations to workers were calculated from the time-activity pattern and the mapping data. In the iron foundry plant, the worker with the highest exposure level was the crane driver whose average exposure levels of nanoparticle number concentrations and nanoparticle mass concentrations were found to be 5.17x104 □/cm3 and 11.39 □g /m3, respectively.