Urban VOC emissions contribute to smog through formation of ozone and secondary organic aerosol (SOA). Quantifying urban VOC sources is a major challenge of importance for air quality and for understanding the reactive carbon cycle. This project will help address this challenge by directly quantifying the urban flux of reactive carbon flux by eddy covariance. Specifically, the project applies two complimentary time-of-flight chemical ionization mass spectrometers to measure fluxes, gradients, and concentrations of an expansive suite of reactive VOCs from a tower in metropolitan New York as part of AEROMMA. The measurements will make a key contribution to the broader AEROMMA campaign by sampling a predominantly residential footprint that represents a critical component of the diverse NY landscape. The project provides significant broader impacts to the scientific community and to the general public through: i) enhanced VOC understanding for improving atmospheric models, ii) better source apportionment for more accurate air quality predictions, and iii) unique opportunities for public engagement around the science of air pollution.