Summer Aerosol and Trace Gas Observations in Houston, Texas, Using an Adaptable Mobile Facility

Abstract An aerosol container featuring a shared inlet system was deployed to Houston, Texas, in July 2022, enabling direct, high-time-resolution in situ measurements of aerosols and trace gases. The internal rack system and floorplan were designed for adaptable modularity to elucidate aerosol physicochemical processes at fine scales. The design allowed for the deployment of a core instrument suite and additional customized research grade instruments. A heterogeneous mixture of aerosols was observed during three regimes: 1) intermittent black carbon (BC) and diurnal variations in aerosol chemical composition, 2) observed particle growth associated with sulfur dioxide (SO 2 ), and 3) transported supermicron dust. The high variability of observed particles and gases in high time resolution indicated a complex urban area with multiple local and regional sources and processes. Particle growth rates of 7–16 nm h −1 were observed for submicron particles during periods when SO 2 was >0.5 ppbv. Two periods of multiday long-range transport events of dust from the African Sahara were observed in the supermicron and submicron particle modes with total mass concentrations up to 30 μ g m −3 . Aerosol scattering Ångström exponents and extinction coefficients B ext increased with humidity as a function of particle composition. The measurements demonstrate collaborative capabilities that can be used to increase observations of aerosol processing, microphysical and optical properties, internal mixing state, and supermicron aerosol that are not parameterized or missing in global Earth energy system models. Significance Statement A modular and adaptive field-deployable mobile facility for conducting atmospheric research was developed to sample aerosol and trace gases in real time and in high time resolution (on the order of seconds to minutes). The container includes an aerosol and trace gas inlet designed to minimize transmission loss, integrated instrumentation for aerosol properties and trace gas, and an adaptable space to tailor deployments for campaign-specific science goals. During this first field deployment in Houston, Texas, different aerosol regimes were isolated allowing for direct characterization of aerosol processes. The collaborative capabilities were designed to enable unique measurements of aerosol optical properties, water uptake, cloud formation potential, and chemical composition to understand how sources, aging, and mixing affect energy within the Earth systems.