GOTHAAM

Why It Matters - Understanding how chemical processes change throughout the diel cycle improves air-quality forecasts and guides smarter strategies to reduce ozone and harmful airborne particles in urban areas. 

GOTHAAM investigated how atmospheric chemical oxidation processes unfold over the diel cycle in the Greater New York City region during summer.

The objectives included:

• identifying and quantifying the contributions of volatile organic compounds from consumer products (VCPs), fossil fuel-derived sources (VOCff), and natural plant emissions (BVOC) to OH reactivity, ozone formation, and secondary organic aerosol (SOA) formation during different meteorological conditions;
• determining the relative importance of different oxidation pathways that drive VOC processing and SOA evolution during daytime;
• quantifying nighttime oxidation processes, including the role and partitioning of reservoir species such as ClNO2, and assessing how nighttime chemistry influences next morning chemical reactions and aerosol loading;
• providing a rigorous evaluation of chemical mechanisms in state-of-the-art chemistry transport models.