Abstract
Organic aerosols are ubiquitous in the earth’s atmosphere. They have been extensively studied in urban, rural and marine environments. However, little is known about the fluorescence properties of water-soluble organic carbon (WSOC) or their transport to and distribution in the polar regions. Here, we present evidence that fluorescent WSOC is a substantial component of High Arctic aerosols. The ratios of fluorescence intensity of protein-like peak to humic-like peak generally increased from dark winter to early summer, indicating an enhanced contribution of protein-like organics from the ocean to Arctic aerosols after the polar sunrise. Such a seasonal pattern is in agreement with an increase of stable carbon isotope ratios of total carbon (δ13CTC) from −26.8‰ to −22.5‰. Our results suggest that Arctic aerosols are derived from a combination of the long-range transport of terrestrial organics and local sea-to-air emission of marine organics, with an estimated contribution from the latter of 8.7–77% (mean 45%).
Highlights
Organic aerosols are ubiquitous in the earth’s atmosphere
Our results suggest that Arctic aerosols are derived from a combination of the long-range transport of terrestrial organics and local sea-to-air emission of marine organics, with an estimated contribution from the latter of 8.7–77%
The objective of this study was to investigate the excitation-emission matrix (EEM) properties of water-soluble organic carbon (WSOC) in Arctic aerosols collected at Alert, in the Canadian High Arctic (Figure 1a), in order to understand the influence of marine organics to organic aerosols in the Arctic atmosphere
Summary
Organic aerosols are ubiquitous in the earth’s atmosphere. They have been extensively studied in urban, rural and marine environments. The ratios of fluorescence intensity of protein-like peak to humic-like peak generally increased from dark winter to early summer, indicating an enhanced contribution of protein-like organics from the ocean to Arctic aerosols after the polar sunrise. Fluorescence techniques (e.g. synchronous scan and excitation-emission matrix spectroscopy) have been widely used to investigate the sources and optical properties of dissolved organic matter (DOM) or humic substances in aquatic environments[12,13,14,15]. Such techniques are widely applied to study the sources and chemical nature of chromophoric DOM (CDOM) in oceans[16,17]. Little is known about the changes in optical characteristics and sources of bulk organic aerosols before and after polar sunrise
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