Research in the Kahan lab focuses on four main topics.
Reactivity at ice surfaces
Organic pollutants such as polycyclic aromatic hydrocarbons (PAHs) are ubiquitous in the environment. They can be found in the air as well as in lakes and rivers, in snow, and on surfaces such as roads and buildings. Their reactions in the environment often lead to the formation of more toxic compounds. Recently it has been discovered that their reactivity in snow and ice can be significantly different from that in liquid water. We use spectroscopy and microscopy to measure reaction kinetics of pollutants in snow and ice.
Fate of pollutants in natural waters
Many natural such as oceans, lakes and rivers contain organic pollutants. These pollutants are considered to be one of the greatest dangers to underwater life including fish, mammals, and coral reefs. The products formed from reactions of organic pollutants in natural waters can be more toxic than the parent compounds
Natural waters can contain high concentrations of solutes such as salts and organic matter. This complex composition makes predicting the fate of pollutants in natural waters very difficult. We examine the effects of individual components of natural waters on reaction rates of organic pollutants and compare these to reaction rates measured in real waters in order to better understand and predict the fate of organic pollutants in oceans, lakes, and rivers.
Chemistry at urban surfaces
Surfaces such as roads and buildings are coated with collections of particles. Chemistry on these surfaces can be very different from that in the gas phase. We use spectroscopy, microscopy, and other tools of physical and analytical chemistry to investigate interactions between gas-phase molecules and urban surface coatings.
Most studies of atmospheric chemistry have focused on the outdoors, but people spend on average more than 90% of their time indoors. We investigate reactions that can be initiated by artificial light sources and sunlight filtered through windows to determine the effects of photochemistry on indoor air quality.