Shapes in submicron ammonium sulfate particles after long-term exposure on tree leaves

Assessing the effects of air pollutants, including aerosols, on trees is important for protecting forests in the future. This study determined the adsorption of particles on trees after 1- or 2-year long-term exposure (for 1 or 2 h/day) to submicron-scale ammonium sulfate (AS) particles using a field-emission scanning electron microscope (FE-SEM). Energy-dispersive X-ray spectroscopy (EDX) was also used to distinguish particles resulting from exposure from those present on the leaves under natural conditions prior to the 1- or 2-year exposure. We found submicron-sized AS particles were deposited on the leaf surfaces of four tree species after long-term exposure in a growth chamber