PURPOSES : A pilot experimental study on the formation of fine particulate matter through photochemical reactions using precursor gas species (volatile organic compounds (VOCs), NH3, SO2, and NOx) was conducted to evaluate the large-scale environment chamber for investigating the pathway of aerosol formation and the subsequent assessment techniques used for reducing fine particulate matter. Two small-scale environment chambers (one experimental group and one control group), each with a width, depth, and height of 3 m, 2 m, and 2.3 m, respectively, were constructed using ethylene tetrafluoroethylene (ETFE) films. METHODS : The initial conditions of the fine particles and precursor gases (NOx and VOCs) for the small-scale environment chamber were set up by injecting diesel vehicle exhaust. NH3 and H2O2 were added to the small-scale environment chamber for the photochemical reaction to form organic and inorganic aerosols. The gas phase of the VOCs and the chemical compositions of aerosols were investigated using a proton transfer reaction time-of-flight mass spectrometer and the aerodyne high-resolution time-of-flight aerosol mass spectrometer at 1 and 10 s time resolutions, respectively. Gas phases of NO and NO2 were measured using Serinus 40 NOx at a 20 s time resolution. RESULTS : The small-scale environment chambers built using ETFE films were proved to supply sufficient natural sunlight for the photochemical reaction in the environment chambers at an average of approximately 89% natural sunlight transmission at 300–1000 nm. When the intermediates of NH3 and H2O2 for the atmospheric chemical reaction were injected for the initial condition of the small-scale environment chamber, nitrate and ammonium in the experimental group increased to 4747% and 1837%, respectively, compared to the initial concentrations (5.4 μg/m3 of nitrate and 5.2 μg/m3 of ammonium), indicating the formation of secondary inorganic aerosols of ammonium nitrate (NH4NO3). This implies that it is necessary to inject intermediates (NH3 and H2O2) for the formation of fine particulate matter when simulating the atmospheric photochemical reaction for assessing the environment chamber. CONCLUSIONS : This study has shown that small-scale environment chambers can simulate the atmospheric photochemical reaction for the reduction of fine particulate matter and the formation of the aerosol pathway. The results of this study can be applied to prevent time and economic losses that may be incurred in a full-scale environment chamber.