Abstract
A low-flow miniature differential mobility analyzer (mDMA) has been developed for compact field-portable mobility spectrometers to classify the submicrometer aerosol. The mDMA was designed for an ultra-low aerosol flow rate of 0.05 L/min. At a sheath flow rate of 0.2 L/min, the mDMA's upper size limit was estimated to be about 921 nm. The mDMA has a classification zone of 2.54 cm long, an outer diameter of 2.54 cm, and an inner diameter of 1.778 cm. The design allows low-cost fabrication and easy assembly. Tandem DMA (TDMA) measurements were carried out to evaluate the performance of the mDMA. Its transfer function was described using Stolzenburg's model. The experimentally measured transfer function shows close agreement with the theory. The transmission efficiency was comparable to that of the Knutson-Whitby DMA for particles in the range of 10-1000 nm. The mobility resolution was comparable to that of the TSI 3085 nanoDMA at the same aerosol flow rate. The design features and performance of the mDMA make it suitable for compact field portable mobility size spectrometers for measurement of nanoparticles and submicrometer aerosol.
Highlights
Recent growth in broad applications of nanotechnology has led to increase in industrial production of engineered nanomaterials
Several direct-reading instruments are available for workplace aerosol monitoring, that include hand-held condensation particle counters (CPCs), photometers, and surface area monitors, scanning mobility particle sizers, and electrical impactors (Methner et al 2010; NIOSH 2013; Ramachandran et al 2011)
We describe development of a compact, hand-portable, battery-operated mobility spectrometer that is suitable for aerosol size distribution measurement for personal, mobile, or distributed sampling applications
Summary
Recent growth in broad applications of nanotechnology has led to increase in industrial production of engineered nanomaterials. Larger mobility spectrometers provide number-weighted particle size distribution, which can be used to obtain an estimation of all three exposure metrics in a single measurement. These instruments are not suitable for routine field use due to high cost, large weight or high complexity of use. Other field-portable instruments, such as the NanoID (Particle Measuring Systems), NanoScan (TSI Inc.) and a hand-held particle size spectrometer (Qi and Kulkarni 2012) have been developed to measure the mobility size distribution These instruments use a unipolar charger for charge-conditioning, which can introduce large measurement uncertainties for aerosols with preexisting charges (Qi et al, 2009) and limit the measurement size range (Qi and Kulkarni 2012). Key design features of each component are briefly described below
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Aerosol science and technology : the journal of the American Association for Aerosol Research
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
