Pfeifer G D, Harrison R M, Lynam D R
Air Conservation, Department, Ethyl Corporation, Richmond, VA 23218, USA.
Sci Total Environ. 1999 Sep 1;235(1-3):253-60. doi: 10.1016/s0048-9697(99)00201-6.
In 1995, a petroleum marketer introduced a diesel fuel additive in the UK containing Mn as MMT (methylcyclopentadienyl manganese tricarbonyl). A small study of personal exposures to airborne Mn in London was conducted before and after introduction of the additive to identify any major impact of the additive on exposures. In 1995, personal exposures to Mn were measured in two groups, taxi drivers and office workers (10 subjects per group) for two consecutive 7-day periods. A similar study was carried out in 1996 to determine if exposures had changed. Samples were also analyzed for Ca, Al, Mg and Pb. In 1996, exposures to aerosol mass as total suspended particulates (TSP) and PM2.5 were measured in addition to the metals. Manganese exposures in this cohort did not increase as a result of introduction of the additive. However, a significant source of Mn exposure was discovered during the conduct of these tests. The mean exposure to Mn was higher among the office workers in both years than that of the taxi drivers. This was due to the fact that approximately half of the office workers commuted via the underground railway system where airborne dust and metal concentrations are significantly elevated over those in the general environment. Similar results have been noted in other cities having underground rail systems. Exposure to Mn, Pb, Ca, and Mg were not significantly different between the 2 years. Taxi drivers had higher exposures than office workers to Mg and Pb in both years. Commuting via the underground also had a significant impact on exposures to TSP, PM2.5, Al, and Ca, but had little effect on exposures to Mg. The aerosol in the underground was particularly enriched in Mn, approximately 10-fold, when compared to the aerosol in the general environment. There are several possible sources for this Mn, including mechanical wear of the steel wheels on the steel rais, vaporization of metal from sparking of the third rail, or brake wear.
1995年，一家石油营销商在英国推出了一种含锰的柴油燃料添加剂，锰以甲基环戊二烯三羰基锰（MMT）的形式存在。在该添加剂引入前后，针对伦敦地区个人空气中锰暴露情况开展了一项小型研究，以确定该添加剂对暴露情况的任何重大影响。1995年，对两组人员（出租车司机和办公室职员，每组10名受试者）连续两个7天期间的个人锰暴露情况进行了测量。1996年进行了类似研究，以确定暴露情况是否发生了变化。还对样本进行了钙、铝、镁和铅的分析。1996年，除了金属之外，还测量了作为总悬浮颗粒物（TSP）和气态细颗粒物（PM2.5）的气溶胶质量暴露情况。该队列中的锰暴露并未因添加剂的引入而增加。然而，在进行这些测试期间发现了一个重要的锰暴露源。在这两年中，办公室职员的平均锰暴露量均高于出租车司机。这是因为大约一半的办公室职员乘坐地铁通勤，地铁中的空气尘埃和金属浓度明显高于一般环境。在其他拥有地铁系统的城市也发现了类似结果。两年间锰、铅、钙和镁的暴露情况无显著差异。在这两年中，出租车司机的镁和铅暴露量均高于办公室职员。乘坐地铁通勤对TSP、PM2.5、铝和钙的暴露也有重大影响，但对镁的暴露影响较小。与一般环境中的气溶胶相比，地铁中的气溶胶锰含量特别高，约为10倍。这种锰有几种可能的来源，包括钢轮在钢轨上的机械磨损、第三轨火花产生的金属汽化或刹车磨损。
