NOx and Ozone Measurement Group

The NO_x and Ozone measurement group, composed by Alessandro Franchin (PI), and Changmin Cho, (previously led by Andy Weinheimer) specializes in airborne measurements of NO, NO₂, and ozone at high time resolution (1 Hz) and at high precision. The measurements of these reactive species are fundamental for the interpretation of the processes in the atmosphere. Our NO_x instrumentation is currently based on chemiluminescence and is among the most sensitive technique available. We are also working on developing a new state-of-the-art instrument based on laser-induced fluorescence (LIF). Our community requestable instruments have been extensively employed since the mid 2000s on many NSF- and NASA-funded field campaigns, enabling the success of more than 25 measurement projects and a remarkable scientific output of more than 70 peer reviewed publications. Our scientific interests include investigating the effects of the Asian Summer Monsoon anticyclone on the chemical processes in the global upper troposphere and lower stratosphere, how its transport of chemicals affects ozone chemistry, short-lived climate forcers, and aerosols’ radiative impact (see ACCLIP web page); examining the composition and chemistry of smoke from wildfires and managed/agricultural burning to better understand the impact of smoke on partitioning of reactive nitrogen, and more broadly on air quality and climate (see FIREX-AQ and WE-CAN pages); studying the factors controlling air quality in urban areas and how human-made emissions (e.g., from power plants, cars, industry) interact with biogenic emissions downwind from forests and what is their chemical evolution (see KORUS-AQ and GOTHAAM pages).

	Photo 1. Taken from the NASA DC8 aircraft during the ASIA-AQ campaign in 2024. Photo credit: Alessandro Franchin
	Photo 2. Taken from the NSF/NCAR GV aircraft during the ACCLIP campaign in 2022. Photo credit: Alessandro Franchin
	Photo 3. Taken during the FIREX-AQ campaign from the N48 NOAA Twin Otter while measuring the emissions from the 204 Cow fire, close to the Idaho-Oregon border, on 25 August 2019.  Photo credit: Alessandro Franchin