Submicron-sized airborne particulate matter (PM) is not collected well on regular quartz or glass fiber filter papers. We used a micro-orifice uniform deposit impactor (MOUDI) to fractionate PM into 6 size fractions and deposit it on specially designed high-purity thin aluminum disks. The MOUDI separated PM into fractions 56–100, 100–180, 180–320, 320–560, 560–1000, and 1000–1800 nm. Since the MOUDI has a low flow rate (30 L/min), it takes several days to collect sufficient carbon on 47-mm foil disks. The small carbon mass (20–200 μg C) and large aluminum substrate (∼25 mg Al) present several challenges to production of graphite targets for accelerator mass spectrometry (AMS) analysis. The Al foil consumes large amounts of oxygen as it is heated and tends to melt into quartz combustion tubes, causing gas leaks. We describe sample processing techniques to reliably produce graphitic targets for 14C AMS analysis of PM deposited on Al impact foils.

中文翻译：

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测量铝撞击盘上的亚微米级分馏颗粒物

常规石英或玻璃纤维滤纸无法很好地收集亚微米级空气悬浮颗粒物 (PM)。我们使用微孔均匀沉积冲击器 (MOUDI) 将 PM 分成 6 种尺寸的部分，并将其沉积在专门设计的高纯度薄铝盘上。MOUDI 将 PM 分离为 56–100、100–180、180–320、320–560、560–1000 和 1000–1800 nm 的部分。由于 MOUDI 的流速较低（30 L/min），因此需要几天时间才能在 47 毫米箔盘上收集足够的碳。小碳质量（20-200 μg C）和大铝基板（~25 mg Al）对生产用于加速器质谱（AMS）分析的石墨靶提出了一些挑战。铝箔在加热时会消耗大量氧气，并容易熔化成石英燃烧管，导致气体泄漏。14沉积在铝冲击箔上的 PM 的 C AMS 分析。