A coupled atmospheric simulation chamber system for the production of realistic aerosols and preclinical model exposure

Abstract

Atmospheric simulation chambers can become valuable tools for studying the impact of different air pollutants and sources on preclinical models. We developed a novel experimental approach for the generation of realistic polluted atmospheres, by coupling, for the first time, two advanced chambers, the FORTH (Foundation for Research & Technology—Hellas) mobile simulation chamber and the CESAM (Chamber for Experimental Multiphase Atmospheric Simulation) chamber, to continuously generate air pollution levels that represent a variety of urban atmospheric conditions heavily influenced by biomass burning (BB). The combination of the two chambers enables the production of stable and representative aerosols, allowing for long-term exposure studies on preclinical models (i.e., healthy, and wild type mice) under controlled conditions. This work describes the coupling methodology, the operational conditions of the FORTH and CESAM chambers and the integration of the animal exposure devices to this dual chamber set-up. The protocols applied for the continuous production (here up to 72 h) of both fresh and aged BB emissions and several other pollutants are described. The range of aerosol concentrations, compositions, and properties achieved in these experiments are summarized. The aged BB aerosol had up to twice the oxidative potential (OP) of the fresh BB emissions. The study revealed significant changes in aerosol composition during the photochemical processing of the BB emissions, with the oxygen to carbon (O:C) ratio of aged BB increasing by 33% compared to the fresh. Notable volatile organic compounds (VOC) emissions, such as formaldehyde and acetonitrile, and their levels were also highlighted. The main objective of this work is to provide useful insights for the future development of robust protocols for effective long-term exposure (several days or weeks) of preclinical models under controlled and stable conditions.