B3: Comparing Volatile Organic Compound Concentrations in St. Louis and Chicago

Presenter(s)

Jamie Kamp

Abstract or Description

Volatile organic compounds (VOCs) originate from various biogenic and anthropogenic sources and are key precursors to tropospheric ozone, a hazardous pollutant linked to respiratory and circulatory issues. Understanding the VOCs present in a region is essential for classifying its ozone chemical regime, which in turn is critical for developing effective policies targeted to reducing ambient ozone concentrations. This study aimed to deepen our understanding of urban VOCs by analyzing ambient air samples from Chicago and St. Louis over a one-week period by using gas chromatography with a photoionization detector (GC-PID). I focused on three key VOCs: benzene, toluene, and isoprene, which are representative emissions from both biogenic and anthropogenic sources. Time series plots and diurnal trends revealed that isoprene exhibited an afternoon peak in both cities, with significantly higher concentrations and a more pronounced trend in St. Louis compared to Chicago. Additionally, benzene and toluene displayed strong peaks during morning and evening rush hours, with elevated levels often persisting into the night. Chicago generally had higher concentrations of these VOCs. Every city is unique, and there is no "one size fits all" method for reducing ambient ozone concentrations. In the face of climate change, an improved understanding of VOCs is essential for developing city-specific solutions.