Adsorbed non-polar organic species on inhalable gamma-alumina particles

Alumina refining is a multi-billion-dollar industry in Western Australia (WA) where residents living in close proximity to the alumina refineries have raised concerns regarding health issues related to refinery emissions. Traditionally, alumina refinery gaseous or particulate matter emission levels are measured separately and do not include the combination of both, such as organics adsorbed on to particles. The adsorption and desorption of volatile organic compounds (VOCs) including n-hexane, benzene, toluene and o-, m-, p-xylene on/from gamma-alumina particles was investigated using thermal desorption gas chromatography mass spectrometry (TD-GCMS). Results from both adsorption and desorption studies show that these VOCs, found in alumina refinery emissions, adsorb and concentrate on gamma-alumina particles and then desorb when the humidity is raised. Consequently, a new approach to determining exposure standards of inhaled air pollutants particles with adsorbed organic compounds may be required.