AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
An Aerosol Particle Monitor for Use in Micro-Gravity Cabin Exposure Studies
NATHAN KREISBERG, Steven Spielman, Gregory Lewis, Susanne Hering, Tim Gordon, Gavin McMeeking, Aerosol Dynamics Inc
Abstract Number: 750 Working Group: Instrumentation and Methods
Abstract Given the majority of personal exposure to airborne particulates occurs indoors, instrumental methods are needed tailored to different indoor environments. One novel environment is micro-gravity aerospace cabins such as the International Space Station (ISS) that impose operational constraints and significant limits on size, power, and permissible materials. Despite active filtration measures in place, little is known about potential human exposure to particulates including concentration and size. The absence of gravitational settling greatly extends the range of interest for particle size. A real-time monitor is needed to correlate human activity believed to be the primary source of particle generation. Here we describe the adaptation of two traditional particle measurement technologies, condensation particle counting and light scattering particle sizing, into an aerosol particle monitor (APM) for use on the ISS.
In a compact, integrated package the APM incorporates a modified water condensation particle counter (WCPC) and a modified commercially available portable optical particle spectrometer (POPS). To avoid water handling or use of a reservoir, a water recycling system was developed for the WCPC enabling startup from a dry state (i.e. liquid-free launch) by harvesting moisture from the cabin. A virtual impactor stage, designed using numerical modeling, was built into the inlet to compensate for the low flow of the spectrometer while coupling them was facilitated through conversion of the POPS to use a re-circulating sheath flow. Additionally, the size range of the POS was modified to extend particle sizing from the original 0.2-3 µm to 1-10 µm to complement the fine aerosol concentration measured by the WCPC. This shift in range is fully reversible so that the original POPS size range can be easily recovered. The benefits of long term, unattended operation of the APM design extend to other environments needing real-time, continuous particle monitoring.