Amir Naqwi — MSP Corporation
Francisco Romay — MSP Corporation
Category
General Topics – Aerosol
Description
Real-time cascade impactor; insets show the preliminary test results and the inside of a stage
Authors (in alphabetical order): Modi Chen, Lin Li, Virgil Marple, Amir Naqwi, Francisco Romay, James C. Wilson
Abstract:
This report covers research conducted under DOE sponsorship pertaining to atmospheric aerosols that play an important role in climate change. This project has been concerned with the development of instrumentation for airplane-based aerosol measurements. Applicant organization, MSP Corporation, has modified and upgraded its aerosol sampling instrument MOUDI to provide real-time measurements. This instrument consists of multiple stages, and at each stage, aerosols of a certain size class are deposited on an impaction plate. When used aboard an aerial vehicle, conventional MOUDI allowed determination of accumulated aerosol masses in each size class for the entire flight trajectory, because the aerosol mass was determined through laboratory analysis on the ground. Detailed information such as differences between the aerosol size distribution near and far from a cloud and the effect of altitude on the aerosol size distribution has not been available. Hence, the objective of the present research has been to investigate the feasibility of sensor technologies that would enable real-time mass measurements at each stage of a MOUDI-type instrument.
As shown in the attached image, quartz-crystal microbalances (QCM) are now mounted to Stage 6 - 13 of MOUDI that cover an aerosol size range of 10 - 600 nm, which is of most interest in several atmospheric applications (Stages 1 - 5 covering larger particles up to 18 micron are not included in the current design). The newly developed instrument is currently being tested. Our poster presentation will include the data of real-time measurements, which will be compared with off-line conventional analysis.
By the end of this project in April 2015, MSP expects to have a fully-functional flight-worthy instrument that will include a heater to heat the incoming air sample to 25 C, in order to measure the dry aerosol mass. It will also include a humidifier to study the hygroscopic properties of the collected sample.
