A Miniature Monitor for Time-Resolved Airborne Particle Chemistry

DESCRIPTION (provided by applicant): A miniature "growth tube collector" will be developed to provide the concentrated collection of multiple, sequential airborne particle samples directly onto a "collection wafer". This instrument will encapsulate individual particles within micrometer-diameter water droplets that are collected by impaction. This condensational enlargement is achieved using a new technology developed for our water-based condensation particle counters whereby particles as small as a few nanometers are enlarged to a size of several micrometers in a thermally diffusive, laminar flow. Once enlarged the particles are readily collected onto the "wafer" by inertial means. Sequential samples will be collected on the same wafer to provide time resolution. The collection wafer will be tailored to readily interface with laboratory-on-a-chip or standard ion chromatography methods to permit cost-effective chemical analysis with minimal sample handling. This approach will permit time-resolved chemical characterization of airborne fine particles in homes, schools, buses, offices, industrial work places and as a personal monitor. Small, airborne particles are associated with adverse health effects, with visibility degradation, and climate change. Proposed is a miniature, cost-effective collector for determining hourly concentrations of the major chemical constituents found in these particles.