Jong-sang Youn

Environmental Health Sciences / College of Public Health

On the Nature of Aerosol Physicochemical Properties and Health Effects in the Southern Arizona
Aerosol particles are a highly relevant component in the Earth’s atmosphere. They have effects on air quality, human health, the planet’s energy balance, and the hydrological cycle. Quantifying these aerosol effects is difficult due to limited understanding of aerosol particle properties and how such properties translate into interactions with solar radiation and water vapor. To improve forecasting of aerosol effects, more aerosol measurements are needed that can inform model parameterizations. An excellent natural laboratory to conduct such an investigation is Southern Arizona, which includes the city of Tucson. This is a rapidly growing urban area potentially moving towards a more arid regime due to hotter, drier conditions, which will result in increased atmospheric dust emission and frequency of wildfires. This area is also characterized by a high density of mining emissions, which leads to enhanced levels of toxic metals and metalloids in the air that can harm a large vulnerable population. The proposed work is focused on advancing knowledge of aerosol physicochemical properties, specifically composition characteristics and water-uptake behavior (i.e. hygroscopicity), the latter of which is critical to understanding how particles swell upon inhalation in living beings and where they deposit in the respiratory system. Measurement data will be coupled to a model to predict deposition behavior upon inhalation. The main topics of this research include the following: (1) Characterization of the factors governing the temporal distribution of carbonaceous aerosol components in southern Arizona; (2) characterization of the hygroscopic behavior of aerosol in southern Arizona and its health effects as predicted by a model.