空氣中無機酸實務採樣與模擬採樣之探討

無機酸在工業上廣泛被使用，如:表面處理業、金屬製品業、機械零件製造業及電子半導體業。以金屬表面處理為例，在電鍍及陽極處理製程常使用硫酸、鹽酸及硝酸等進行酸性脫脂、酸洗除鏽，電解液中也常添加磷酸、硫酸。由於其用途廣泛，因此許多勞工在工作上無法避免接觸到這些物質，而長期暴露此類物質，輕則刺激皮膚、呼吸道或出現咳嗽、胸悶，重則可能引發氣管炎、肺炎及肺水腫等呼吸系統疾病。由於過往無機酸採樣皆發現現場酸霧嚴重，但使用 CLA 2901 採樣時皆僅有低量的無機酸暴露，為瞭解造成此現象之原因，本研究擬以模擬及實務無機酸採樣來探討造成此狀況之原因，以正確掌握勞工作業環境暴露實態，保護勞工身心健康。本研究於實驗室進行模擬採樣，並挑選四家金屬表面處理工廠對無機酸進行空氣採樣，並皆使用我國勞動部建議採樣方法 CLA 2901 及美國公布的NIOSH 7907、NIOSH 7908 進行，以比較三種採樣方法於實務與模擬結果，並探討其捕集效果差異之原因。於實驗室進行定濃度模擬採樣，結果發現，以矽膠管作為採樣介質時，除了鹽酸作為發散源，採集之樣本有分析到濃度，其他三種酸之採集樣本皆小於偵測極限，同樣發散源，使用石英濾紙作為介質時，捕集效率明顯較矽膠管好。為了更一步瞭解兩種方法於實務上的採樣情形，而在四間工廠進行空氣採樣，分析結果顯示無機酸之濃度均無超過法定規範之標準，但有一些區域有監測到無機酸暴露，像是:B 廠樣本 6 (鹽酸濃度 6.91E-02 ppm)、C 廠樣本 8 (鹽酸濃度 5.52E-01 ppm)及 D 廠樣本 6 (硝酸濃度 8.15E-02 ppm)等，人員於該區進行作業時，仍須注意；結果發現位於同一位置進行採樣，使用 CLA 2901 採集之樣本大部分均小於偵測極限，而 NIOSH 7907 及 NIOSH 7908 之採集樣本，則有測得濃度。在採樣分析方法比較，發現精密度在 NIOSH 7907、NIOSH 7908和 CLA 2901 的差異不大，但準確度 NIOSH 7907、NIOSH 7908 較 CLA 2901高。這結果顯示以矽膠管採樣時，由於採樣幫浦持續抽氣，無機酸無法被持續吸附在矽膠管內，有出現脫附現象，造成以 CLA 2901 採樣時，樣本濃度偏低，甚至低於偵測極限。碳酸鈉在濾紙上，會因為酸鹼中和之原因形成鹽類，雖然採樣幫浦持續抽氣，但不會出現脫附現象，因此採用 NIOSH 7907 捕集鹽酸與硝酸時，效率較 CLA 2901 為佳；而濾紙相較於矽膠管，對於粒狀污染物捕及效率較好，因此，使用 NIOSH 7908 採集硫酸與磷酸時，效率又較 CLA 2901 為佳。我國現行對無機酸作業場所進行作業環境監測時，大部分還是參考 CLA 2901 方法進行，基於捕集效率問題，建議修改標準參考分析方法，採用較佳之NIOSH 7907 與 NIOSH 7908 之採樣方法，以增加作業環境監測的準確性，而後續也可以研究將濾紙浸敷碳酸鈉作為採樣介質，探討與未浸敷碳酸鈉濾紙之硫酸與磷酸捕集效率，確保勞工健康與安全。

關鍵字

無機酸；表面處理；空氣採樣； CLA 2901 ； NIOSH 7907 ； NIOSH 7908

並列摘要

Inorganic acids are widely used in industry, such as surface treatment, metal products,mechanical parts manufacturing and electronic semiconductor. Taking metal surface treatment as an example, sulfuric acid, hydrochloric acid and nitric acid are often used for acid degreasing, pickling and rust removal in electroplating and anodizing processes. Phosphoric acid and sulfuric acid are often added to the electrolyte. Due to its wide rangeof uses, many workers cannot avoid exposuring themselves into those substances at work.Long-term exposure to such substances may irritate the skin, respiratory tract, cough and chest tightness, and may cause bronchitis, pneumonia, and pulmonary edema. Since the previous inorganic acid sampling was found severe acid fog on site, but only a low amount of inorganic acid exposure was found when using CLA 2901 for sampling. The reasons for the situation, to correctly grasping the actual situation of exposure of labor working environment, to protecting the physical and mental health of labor. In this study, simulated sampling was carried out in the laboratory, and four metal surface treatment plants were selected to conduct air sampling for inorganic acids, and they were all conducted using the sampling method CLA 2901 recommended by the Ministry of Labor of our country and NIOSH 7907 , NIOSH 7908 published in the United States to compare the three sampling methods. The method is based on the actual and simulated results, and the reasons for the difference in the capture effect are discussed. Simulated sampling at constant concentration was carried out in the laboratory. It was found that when the silicone tube was used as the sampling medium, except for hydrochloric acid as the emission source, the collected samples had the analyzed concentrations. When using quartz filter paper as the medium, the capture efficiency is significantly better than that of the silicone tube. In order to further understand the sampling situation of the two methods in practice, air sampling was carried out in four factories. The analysis results showed that the concentration of inorganic acid did not exceed the legal standard. However, in some areas, mineral acid exposure was monitored, such as Yes: Sample 6 of Factory B (concentration of hydrochloric acid 6.91E-02 ppm), Sample 8 of Factory C (concentration of hydrochloric acid 5.52E-01 ppm) and Sample 6 of Factory D (concentration of nitric acid 8.15E-02 ppm). It is still necessary to pay attention during operation; it was found that the samples were collected at the same location, and most of the samples collected with CLA 2901 were below the detection limit, while the collected samples of NIOSH 7907 and NIOSH 7908 had measured concentrations. In the comparison of sampling and analysis methods, it is found that the precision of NIOSH 7907, NIOSH 7908 and CLA 2901 has little difference, but the accuracy of NIOSH 7907 and NIOSH 7908 is higher than that of CLA 2901. This result shows that when sampling with a silicone tube, due to the continuous pumping of the sampling pump, the inorganic acid cannot be continuously adsorbed in the silicone tube, and desorption occurs. As a result, when sampling with CLA 2901, the sample concentration is low, even lower than the detection limit. Sodium carbonate on the filter paper will form salts due to the neutralization of acid and alkali. Although the sampling pump continues to pump, there will be no desorption phenomenon. Therefore, when using NIOSH 7907 to capture hydrochloric acid and nitric acid, the efficiency is lower than that of CLA 2901. Compared with silica gel tubes, filter paper has better capture efficiency for particulate pollutants. Therefore, when using NIOSH 7908 to collect sulfuric acid and phosphoric acid, the efficiency is better than CLA 2901. Most of the current monitoring of the working environment of inorganic acid workplaces in our country is carried out with reference to the CLA 2901 method. Based on the problem of capture efficiency, it is recommended to revise the standard reference analysis method and use the better sampling methods of NIOSH 7907 and NIOSH 7908 to increase the number of operations. The accuracy of environmental monitoring, and the follow-up can also study the use of filter paper impregnated with sodium carbonate as a sampling medium to explore the capture efficiency of sulfuric acid and phosphoric acid with and without sodium carbonate filter paper to ensure labor health and safety.

並列關鍵字

Inorganic acids ； surface treatment ； air sampling ； CLA 2901 ； NIOSH 7907 ； NIOSH 7908

參考文獻

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