On the ionic composition of aerosol particles and related gas phase species at two sites during the SANA 2 campaign

Abstract

Aerosol particles have been sampled by impactors during the SANA 2 campaign (SANA: Sanitation of the atmosphere) at two sites in eastern Germany and have been analyzed for their ionic composition. The chemical composition of the accumulation mode particles showed a close relation to the diurnal cycles of the temperature and relative humidity. The mass mean radius of sulfate increased with the relative humidity. The presence of nitrate in the accumulation mode was found to be a function of the temperature: At temperatures less than 15°C, nitrate was mainly in accumulation mode particles, at temperatures larger than 20°C, nitrate was mainly in the gas phase as HNO3. Model calculations with the aerosol model MARS showed that the observed chemical composition of the accumulation mode particles agreed with the computed composition. The characteristic time scale to achieve equilibrium between the particles and the gas phase varied and mostly was smaller than ten minutes.

Keywords

• aerosol particles
• accumulation mode
• humidity
• gas phase
• nitrate
• eastern germany
• aerosolteilchen
• akkumulationsbereich
• feuchtigkeit
• gasphase
• nitrat
• ostdeutschland