Tropospheric Chemistry and Composition - Aerosols/Particles

Particles are ubiquitous in the atmosphere. The tropospheric aerosol is remarkably diverse in its composition, reflecting the wide range of particle sources in the atmosphere. Chemical components of tropospheric particles include inorganic materials such as sulfate, ammonium, nitrate, trace metals, and a wide array of carbonaceous compounds. Concentrations of airborne particles vary greatly over the globe, from the lowest concentrations in pristine areas to the highest levels in polluted urban centers. Atmospheric aerosols carry the chemical signature of the sources of direct particle emissions into the atmosphere as well as that of the conversion of gaseous molecules into particulate-phase species.