6533b873fe1ef96bd12d59d2

RESEARCH PRODUCT

Surface modification of mineral dust particles by sulphuric acid processing: implications for CCN and IN abilities

subject

description

Abstract. The ability of coated mineral dust particles to act as cloud condensation nuclei (CCN) and ice nuclei (IN) was investigated at LACIS (Leipzig Aerosol Cloud Interaction Simulator) during the FROST1- and FROST2-campaigns (Freezing of dust). Sulphuric acid was condensed on the particles which afterwards were optionally humidified, treated with ammonia vapour and/or heat. By means of aerosol mass spectrometry we found evidence that processing of mineral dust particles with sulphuric acid leads to surface modifications of the particles. These surface modifications are responsible for the observed reduction of the IN activation of the particles. The observed particle mass spectra suggest that different treatments lead to different chemical reactions on the particle surface. Possible chemical reaction pathways and products are suggested and the implications on IN and CCN efficiency of the treated dust particles are discussed.