Natural and anthropogenic influences on the chemical compositions of marine boundary layer aerosols: A single particle perspective

For many years, the focus of interest in atmospheric chemistry has been the characterization of the physical-chemical properties of gas-phase species present in the atmosphere, and information on the aerosol particles was lacking. In the last decades, our understanding of the role of aerosol particles has deepened, in particular due to the general concern about their effect on climate.; Aerosol time-of-flight mass spectrometry (ATOFMS) is a unique method that allows for real-time measurement of single particle size and chemical composition. Exclusive information can be obtained from single particle mass spectrometry that cannot be obtained from bulk measurements, including information on the associations between chemical species in particles, and degree of reaction/aging. The combination of these desirable features makes an ATOFMS single particle approach for the study of atmospheric aerosols in the marine boundary layer (MBL) very valuable.; The focus of this work is on the ATOFMS on-line characterization of individual particles in different marine environments, such as the Indian Ocean and the Northwest Pacific region, highlighting anthropogenic and natural influences on the aerosol chemical composition, in particular during contrasting meteorological conditions. Special attention is given to the presence of sulfate associations and their consequences on climate change and model predictions. Differences in the outflow of pollutants, and the contribution of biomass burning and fossil fuel combustion to anthropogenic pollution in areas down-wind of South Asia are presented as well. Long range transport of iron-containing dust particles and a possible link with marine phytoplankton productivity and dimethyl sulphide (DMS) emission are discussed.; Results from ATOFMS single particle measurements are presented together with those from traditional standardized aerosol particle chemical analysis and fast-response gas phase analysis, allowing for proper characterization of the chemical properties of the atmospheric aerosol.