title: Aerosol chemical composition in cloud events by high resolution time-of-flight aerosol mass spectrometry.
abstract: This study presents results of direct observations of aerosol chemical composition in clouds. A high-resolution time-of-flight aerosol mass spectrometer was used to make measurements of cloud interstitial particles (INT) and mixed cloud interstitial and droplet residual particles (TOT). The differences between these two are the cloud droplet residuals (RES). Positive matrix factorization analysis of high-resolution mass spectral data sets and theoretical calculations were performed to yield distributions of chemical composition of the INT and RES particles. We observed that less oxidized hydrocarbon-like organic aerosols (HOA) were mainly distributed into the INT particles, whereas more oxidized low-volatile oxygenated OA (LVOOA) mainly in the RES particles. Nitrates existed as organic nitrate and in chemical form of NH(4)NO(3). Organic nitrates accounted for 45% of total nitrates in the INT particles, in clear contrast to 26% in the RES particles. Meanwhile, sulfates coexist in forms of acidic NH(4)HSO(4) and neutralized (NH(4))(2)SO(4). Acidic sulfate made up 64.8% of total sulfates in the INT particles, much higher than 10.7% in the RES particles. The results indicate a possible joint effect of activation ability of aerosol particles, cloud processing, and particle size effects on cloud formation.
authors: Department of Applied Physics, University of Eastern Finland, Kuopio 70211, Finland. hao.liqing@uef.fi
authors: Liqing
authors: L
authors: Hao
authors: Sami
authors: S
authors: Romakkaniemi
authors: Aki
authors: A
authors: Kortelainen
authors: Antti
authors: A
authors: Jaatinen
authors: Harri
authors: H
authors: Portin
authors: Pasi
authors: P
authors: Miettinen
authors: Mika
authors: M
authors: Komppula
authors: Ari
authors: A
authors: Leskinen
authors: Annele
authors: A
authors: Virtanen
authors: James N
authors: JN
authors: Smith
authors: Donna
authors: D
authors: Sueper
authors: Douglas R
authors: DR
authors: Worsnop
authors: Kari E J
authors: KE
authors: Lehtinen
authors: Ari
authors: A
authors: Laaksonen
mesh_terms: D000143:Acids / Q000032:analysis; D000336:Aerosols / Q000737:chemistry*; D001272:Atmosphere; D013058:Mass Spectrometry / Q000379:methods*; D009566:Nitrates / Q000032:analysis; D010316:Particle Size; D013431:Sulfates / Q000032:analysis
chemical_list: D000143:Acids; D000336:Aerosols; D009566:Nitrates; D013431:Sulfates