Piston powered aircraft burning leaded gasoline contribute ~70% of the lead in the atmosphere in the US. The physical size, composition, and structure of aircraft exhaust particles containing lead dibromide are poorly understood and heretofore have not been examined directly by electron microscopy (EM), in particular when captured from an aircraft in flight. To accomplish this, exhaust samples were trapped on EM supports within 10–15 ms of exiting the aircraft exhaust pipe. High angle annular detector dark field scanning EM revealed irregular particles with a mean diameter of 13 nm consisting of a 4 nm microcrystal of lead dibromide surrounded by a halo of hydrocarbons. In contrast, exhaust particles from an automobile burning leaded fuel averaged 35 nm in diameter and contained 5–10, 4 nm lead beads. Of significant concern, the smaller aircraft particles could penetrate mucosal barriers in the lung and be readily taken up by epithelial cells.

燃烧含铅汽油的活塞动力飞机贡献了美国大气中约 70% 的铅。对含有二溴化铅的飞机尾气颗粒的物理尺寸、成分和结构知之甚少，迄今尚未通过电子显微镜 (EM) 直接检查，尤其是从飞行中的飞机上捕获时。为了实现这一点，排气样品在离开飞机排气管后 10-15 毫秒内被捕获在 EM 支架上。高角度环形探测器暗场扫描 EM 显示平均直径为 13 nm 的不规则颗粒，由 4 nm 的二溴化铅微晶组成，周围环绕着一圈碳氢化合物。相比之下，燃烧含铅燃料的汽车排出的废气颗粒平均直径为 35 纳米，含有 5-10, 4 纳米的铅珠。值得关注的是，