Aluminum production is one source of atmospheric polycyclic aromatic hydrocarbons (PAHs), of which benzo[a]pyrene is the best-studied representative. Other high-priority PAHs are attracting increasing attention for differentiation of PAH emissions and sources. Monitoring of these compounds is difficult because PAHs are present in both the solid-phase and gas-phase emissions (with the solid phase containing condensed PAHs); the gas-phase concentration of these substances depends on the manufacturing process temperature and the temperature of the environment. Atmospheric PAH emissions primarily originate from the pot-room ventilation skylights and gas-treatment-unit smokestacks. Low-molecularweight compounds dominate the gas emissions from the pot-room ventilation skylights and posttreatment emissions, while higher molecular weight compounds dominate the gas/dust/air mixture received for treatment. The gas/dust/air mixture received from the pot rooms for treatment by the gas treatment unit and discharged into the atmosphere through the smokestacks shifts the distribution of PAHs present in the atmosphere in favor of light, volatile compounds. The PAHs are close to uniformly distributed between the gas and solid phases of the gas/dust/air mixture emitted from the pot-room skylights. Over 70 wt.% of the PAHs in the emissions downstream of the gas treatment unit are in the gas phase, while the majority of the PAHs entering the gas treatment unit are in the solid phase. The resulting PAH distribution data for the gas/air mixture must be taken into account when developing the techniques for sampling the industrial emissions from the skylights and the atmospheric emissions downstream of the gas treatment unit during aluminum production.

中文翻译：

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铝生产工业排放中气相和固相多环芳烃的浓度分析

铝生产是大气多环芳烃 (PAH) 的来源之一，其中苯并 [a] 芘是研究最多的代表。其他高优先级多环芳烃因区分多环芳烃排放和来源而受到越来越多的关注。监测这些化合物很困难，因为多环芳烃同时存在于固相和气相排放物中（固相含有凝聚的多环芳烃）；这些物质的气相浓度取决于制造过程温度和环境温度。大气多环芳烃排放主要来自罐房通风天窗和气体处理装置烟囱。低分子量化合物在电解室通风天窗的气体排放和后处理排放中占主导地位，而较高分子量的化合物在接受处理的气体/粉尘/空气混合物中占主导地位。从罐房接收的由气体处理装置处理并通过烟囱排放到大气中的气体/灰尘/空气混合物改变了大气中存在的多环芳烃的分布，有利于轻质挥发性化合物。PAHs 接近均匀地分布在从电解室天窗排放的气体/灰尘/空气混合物的气相和固相之间。气体处理单元下游排放物中超过 70 wt.% 的多环芳烃处于气相，而进入气体处理单元的大部分多环芳烃处于固相。