A Chamber-Based Experimental Framework for Comprehensive Mechanistic Studies of Ageing-Driven Changes in Biomass-Burning Aerosol Properties

Abstract. Biomass burning (BB) aerosol particles can significantly impact climate, air quality, and human health. While studies have advanced our understanding of the impact-related properties of the particles, detailed investigations of both driving factors and mechanisms under controlled conditions of dark aging or photooxidation remain limited, especially across fuel types and burn phases. Here, we describe a BB aerosol facility at the University of Manchester that couples an Esse 175F commercial wood-burning stove, housed in a mobile unit outside the main laboratory and supplied with ambient combustion air, to the 18 m³ Manchester Aerosol Chamber. The facility enables batch-mode experiments under controlled dilution, temperature, relative humidity, oxidant exposure, target initial particle mass loading, and dark or illuminated aging conditions. Its batch configuration uses moderate, rather than high, continuous dilution, thereby limiting rapid dilution-induced perturbations while maintaining stable conditions and particle concentrations suitable for filter-based analyses, long-term parallel continuous measurements, and slow-response instruments that are difficult to deploy in short-residence-time flow systems. Measurements include particle size distribution, chemical composition, black carbon, volatility, hygroscopic growth, cloud condensation nuclei activity, optical properties, ice-nucleating ability, and gases. This facility, therefore, provides a repeatable, flexible system and platform for mechanistic and multiparameter investigation of fresh and aged BB aerosol. Experiments conducted in April and September 2022 demonstrated those capabilities across fuel types and combustion phases. They also characterized the facility, showing low background PM levels (<1 µg/m³), with primary gases and PM concentrations typically stabilizing within no more than 10–30 min after smoke injection.