Richard C. Flagan
Irma and Ross McCollum/William H. Corcoran Professor of Chemical Engineering
California Institute of Technology
Pasadena, California

QUANTIFYING AIRBORNE NANOPARTICLES AND ALLERGENS

While epidemiological studies reveal significant increases in cardiovascular disease and other adverse health effects with increasing fine particle mass concentration, they probably underestimate the importance of fine particles because mass is not an effective measure for fine particles. Recent studies reveal profound effects of nanoparticle exposure from diesel trucks - effects that diminish within several hundred meters from the roadway. These observations raise serious safety questions for the rapidly developing nanotechnology industry. At the other end of the aerosol size spectrum, pollen and fungal spores are often associated with asthma even though the particles are too large to penetrate into the lower airways where asthmatic responses originate. Mechanisms have been identified that release pollen allergens as aerosol particles that are small enough to penetrate into the lower airways and trigger asthma. Even though concentrations in the air are small, nanograms to picograms of allergen per cubic meter of air that contains micrograms per cubic meter of other particulate material, these fragments have been linked to asthma epidemics such as "thunderstorm asthma." The health impacts of the two types of particles are linked; some nanoparticles act as adjuvants that increase susceptibility to allergens. This seminar will examine advances in instrumentation that is being developed to quantify and understand these and other health impacts of airborne particles, including (i) a miniature aerosol classifier that uses electrophoretic mobility to probe the nanoparticle size distribution; and (ii) a microtoroidal optical resonator sensor enables antibody assays of unlabeled antigen at the single molecule level.