Development of a Novel Aerosol Electrical-Mobility Analyzer for Large-Scale Air Quality Monitoring

To understand and characterize the impact of aerosol particles on human health, climate, and the environment, accurate measurement of particle properties, particular particle size distribution, is required at high spatial and temporal resolution. While high resolution measurements are possible with commercially available instruments, their high cost, power requirements, and robustness restrict our ability to deploy them for large-scale field measurements. Towards addressing these challenges, an innovative aerosol mobility analyzer that can be deployed as a part of a distributed, telemetric sensing network in urban areas was designed and developed. The design is based on the theory of Miniature Electrical Aerosol Spectrometer (MEAS), a compact mobility sensor previously developed in our group. The MEAS classifies particles based on their electrical mobility and detects the concentration of classified particles by measuring the electric current resulting from the collection of classified particles on individual collection plates. In this thesis, the design of the MEAS was revisited and revised to result in a novel, compact-sized instrument that is ready for field-deployment.;The new instrument, called the printed MEAS (p-MEAS), was specifically designed to ensure its easy manufacturability, low-cost, and compact size. The instrument was designed such that it can be 3D printed and a new particle collector-detector system was incorporated in the instrument to ensure its portability. A new highly sensitive printed electrometer was designed using industry's latest technology on low-level current measurements. An array of these electrometers was integrated with multiple printed collection plates to minimize cost and size of the instrument. To extend the measurement range of particles, a radial geometry for the particle classifier was used. The performance of the integrated instrument design was predicted theoretically and numerically, and the predictions were verified experimentally. The experimental results suggest that the new p-MEAS can measure concentrations of particles in the size range of 10 nm to 1000 nm with a lower concentration detection limit of ~ 105 cm-3.