Dr. Ultman and his colleagues at Pennsylvania State University redesigned their first-generation analyzer that measures the dose of inhaled ozone to reduce electronic noise (interference) and improve the signal's stability. To do so, they adjusted each parameter that influenced the analyzer's performance: the flow of the air sample into the instrument, the pressure in the chamber where the air sample and the reactant gas mixed, the relative amounts of the reactant gas and air sample, and electronic variables (frequency and voltage).