AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Design Criteria and Development of the Next Generation of Butanol CPC’s
AXEL ZERRATH, Andrea Tiwari, Jacob Scheckman, Brian Osmondson, TSI Incorporated
Abstract Number: 379 Working Group: Instrumentation and Methods
Abstract For over four decades Butanol-based Condensation Particle Counters (CPCs) have contributed significantly to the understanding of nanometer-sized particles and their physical properties. As times and research requirements changed, the instrumentation has evolved as well. Again the needs of CPC users and their research activities are leading to new design criteria and the development of 4th generation Butanol-CPCs.
Specialized Butanol-CPCs serve specific research needs such as detecting low concentrations with high sensitivity; measuring high concentrations with accuracy; detecting the smallest, freshly formed particles at the 1 nm threshold; and performing in conjunction with a particle sizer to produce a size spectrum based on number concentration. Further specialization is needed for applications that involve regulations, e.g. the CEN/TS 16976 guideline that harmonizes the measurement of ultrafine particles in the atmosphere for regulatory purposes. This range of requirements resulted in a group of four new Butanol-CPCs being developed at TSI with a couple of focus points in mind:
1. Consistency of results over years of research is very important to get the most out of the data and to make sustainable conclusions. This requirement needs to be balanced with the need for improvements.
2. Various types of research need to cover different ranges of particle sizes. For example, lower (50%) counting efficiency for engine exhaust measurements (23 nm), regulated environmental monitoring (7 nm), particle nucleation process measurements (1 nm), or size distribution measurements using electrical mobility classification (typically between 5 and 10 nm) are all common uses of CPCs, but yet require different CPC models.
3. Field campaigns link laboratory results to applied research. Once the instrumentation is set up in the field, remote control frees up time for the researcher to focus on results instead of maintaining the deployed instruments via time-consuming visits.
4. Quality control also becomes increasingly important in the quantitative measurement of nanometer-sized particles. New enhancements, such as continuous monitoring of the particle-to-droplet growth process using pulse height will support users to ensure data quality.
The results of the characterization of the new set of instruments will be detailed.