Jet exhaust at the airport: HRTEM and XPS analyses

Few studies of aircraft and ground support equipment on airport and regional air quality exist. Transmission electron microscopy (TEM) of jet exhaust particulate matter can provide a direct measure of particle size and their change with respect to engine power. Of particular concern are the innumerable small particles, consisting of organic carbon produced at idle conditions. These likely arise as secondary organic aerosols as a result of volatile condensation. Such particles of < 20 nm size can easily reach the deepest recesses of the lung, the alveoli. As the power changes, so too does the particle black carbon content. Complementing TEM for particle physical size and nanostructure characterization is X-ray Photoelectron Spectroscopy (XPS) for measuring particle surface chemistry, specifically oxygen functional groups such as phenolic (-OH), carbonyl (-C=O) and carboxylic (-COOH). XPS has also revealed a surprising content of heteroelements including Ti, Ba, Co, Fe etc. at levels of tenths of atomic percent and higher in the PM exhaust from some aircraft. Particle size, carbon type and elemental composition each bear health implications for exposure to aircraft generated PM at airports and surrounding neighborhoods.