Development and evaluation of a low-cost aerosol generator for experimental inhalation exposure to particulate matter

To allow inhalation exposure studies, with control of particulate matter (PM) concentration/dose, a low-cost aerosol generator with real-time continual monitoring was developed and tested. This device can be used for comparing controlled laboratory experiments with resuspension of dry ambient PM or dry powders/particles to model atmospheric PM concentrations decoupling the PM sampling and the exposure. Dry powder disposed in a reservoir was resuspended using a generator that promoted the control of flow rates of clean air and containing-PM air for injection in a whole-body exposure chamber continuously monitored by a PM monitor allowing real-time control of PM concentration/dose. To quantify its ability to produce exposure conditions, the airflow dynamics within the exposure chamber with computational fluid dynamics was simulated. A study of PM size distribution and chemical composition was undertaken to compare the ambient and resuspended PM. Airflow circulation patterns show that no areas of stagnation were present; the exposure chamber allows enough dispersion and mixing for the exposure of the mice. While the aerosol generator produces more fine particles, which are a major health concern than coarse particles, it can adequately reproduce the atmosphere with target concentrations. The resuspension in aerosol generator does not cause significative variations in mass ratios of the chemical species that are similar in the ambient and resuspended PM. Overall, this low-cost exposure system can be used in different laboratories, making inhalation exposure techniques more accessible in order to replace more invasive/artificial exposure such as instillation techniques.