Reactive Halogen Species (RHS) impact the levels of ozone and mercury in the atmosphere. However, their levels in the atmosphere are not yet fully understood due to a lack of observations and challenges in modeling their chemistry. The Bermuda Boundary Layer Experiment on the Atmospheric Chemistry of Halogens (BLEACH) aims to fill this observational gap and clarify the sources, chemistry, and impacts of halogens over the open ocean.

Wintertime air pollution affects the health of polar and mid-latitude urban populations. The unique combination of stagnant air at the surface, snow, and increased emissions due to heating lead to some of the highest pollution levels in the United States and around the world. Our participation in the ALaskan Pollution And Chemical Analysis (ALPACA) experiment in Winter 2022 aimed to understand the complex interaction of emissions and vertical mixing as well as the role snow plays during pollution events.

Wildfires are the area they burn are increasing as a consequence of climate change. They are also increasingly contributing to air pollution, even in large urban areas such as Los Angeles. It is thus essential to understand the processes the control the composition of biomass burning plumes. Our group participated in the 2019 NASA-NOAA Fire Influence on Regional to Global Environments and Air Quality (FIREX-AQ) experiment onboard NASA's DC8 aircraft. Using airborne remote sensing we studied emissions of the radical precursors HONO and HCHO, as well as the radiative transfer in the plumes.

The global carbon cycle plays an important role for modulating CO2 mixing ratios in the atmosphere. For many ecosystems it is, however, unclear how climate change will influence plant photosynthesis and carbon uptake. Our group uses novel remote sensing tools to study the carbon cycle in the boreal and tropical forest . We have developed, PhotoSpec, a unique instrument that measures Solar Induced Fluorescence (SIF) and various Vegetation Indices from towers in Costa Rica, Canada and Alaska.

Communities neighboring refineries are exposed to elevated levels of air toxics, such as benzene, ethyl-benzene, toluene, and xylenes (BTEX). To provide refineries and the surrounding neighborhoods with the tools to monitor BTEX, we develop new long-path DOAS instruments that allow accurate observation of BTEX compounds inside the facilities, at the fenceline, and in the neighborhood. Our Optical Tent is currently performing BTEX observations inside and at the fenceline of a refinery in the Los Angeles Basin