Mineral and anthropogenic aerosols in Arabian Sea–atmospheric boundary layer: Sources and spatial variability

To characterize the spatial variations in size segregated aerosols, samples were collected over the Indian and Southern oceans (7°N to 68°S) during the Indian expedition to Southern Ocean (January-February 2010). The chemical and mass concentrations of ions were measured in nine size classes (0.4-> 10 µm) of aerosols through ion-exchange chromatographic system and gravimetric estimates, respectively. Mass concentrations of coarse aerosols increase towards the Antarctic coast which is well correlated with the increasing humidity suggesting growth of particles. The study area was found to be predominately impacted by sea salt aerosols with a sea salt load of 91%. F -, Cl -and NO 3 -reflected anthropogenic impact within the fine mode aerosols but the marine influence dominated the coarse mode. Methanesulphonic (MSA) was predominantly of biogenic origin but a substantially low MSA/nssSO 4 2-ratio suggested that DMS contribution to the total nssSO 4 2-concentration was low. NH 4 + concentrations showed a shift from fine to coarse particles, with a trimodal distribution over the Southern Ocean. Our study reports a significant Cl -depletion in the aerosols and the degree of Cl -deficit was size-dependent, increasing with decreasing particle sizes. The neutralization ratios suggested differential behavior of ions with respect to the prevailing meteorological conditions. The coarse mode aerosols were neutralized by ammonia leading to the formation of NH 4 NO 3 particles. The fine modes were predominately composed of NH 4 HSO 4 and its formation is favored by the high humidity and foggy conditions over the study area. Factor analysis support that the Southern Indian Ocean (10°S to 59°S) had the highest loading of anthropogenic and sea salt aerosols, which lead to the formation of secondary aerosols through gas to particle transformations. The rocky Antarctic coastline, act as a source of coarse crustal aerosols over the Southern Ocean (60°S to 65°S).

Section: Latitudinal Variations In Aerosol Composition and Processes contrasting

confidence: 39%

Section: Latitudinal Variations In Aerosol Composition and Processes mentioning

confidence: 99%

Latitudinal and Size Segregated Compositional Variability of Aerosols over the Indian and Southern Ocean during 2010 Austral Summer

Thakur

Thamban

2014

“…It is known that the spatial variability of Na + and Cl -in atmospheric aerosols are mainly derived from the marine source, more commonly referred to as sea-salts (Quinn et al, 2004;Kumar et al, 2008). This indicates that all the sites experienced a certain marine influence.…”

Section: Chemical Composition Of Pm 10 and Pm 25mentioning

confidence: 99%

Investigation of Desert Dust Contribution to Source Apportionment of PM10 and PM2.5 from a Southern Mediterranean Coast

Kchih

Perrino

Cherif

2015

In order to identify the source apportionment of particulate matter PM 10 and PM 2.5 in the southern Mediterranean coast of Tunis (Tunisia), three different sites characterized respectively by traffic, industries and being an urban background area are studied. The chemical characterization included a gravimetric determination of atmospheric particles mass concentration, measurements of the major anions (SO 4 2-, NO 3 -, Cl -) and cations (Ca 2+ , Mg 2+ , K + , NH 4 + ) concentrations in the aerosol samples by ion chromatography and analysis of 18 elements by energy dispersion X-ray fluorescence. Aerosol ion balance of various PM 10 constituents are used to identify possible sources of the particulate matters. Thanks to these analysis, the particulate masses were reconstructed from the main possible constituents: crustal matter, primary and secondary pollutants, marine aerosols and organic matter. Wherever PM 10 and PM 2.5 were studied, PM 10 crustal elements and sea salt aerosols were mainly associated with the coarse fraction whereas primary and secondary anthropogenic pollutants as well as organic matter rather compose PM 2.5 fraction. In all the sites, PM 10 mass was mainly composed of crustal matter (41-50%) and poorly of sea salt (3-4%). And so aerosols chemical composition is heavily affected by dust winds from Sahara desert, with some contribution of local traffic and industries and only a slight direct impact of the nearby Mediterranean sea.

“…5(b between the regular days and the period after the ADE. The results indicated that oceanic spray was a dominant factor with increasing wind speeds due to strong winds blown by the outflow circulation of Typhoon Doksuri during the period of ADE (Kumar et al, 2008;. This study estimated the amounts of sea-salt particles (SSPs) by using Eq.…”

Section: Spatiotemporal Variation Of Pm 10 Concentration On Regular Dmentioning

confidence: 99%

How Aeolian Dust Deteriorate Ambient Particulate Air Quality along an Expansive River Valley in Southern Taiwan? A Case Study of Typhoon Doksuri

Yuan

2017

Aeolian dust episodes (ADEs) frequently occurred at the bare lands of the riverbeds in Kaoping River are emerging disasters in Southern Taiwan in the past few years. However, their influences on ambient particulate air quality due to the outflow circulation of typhoons have not been addressed in such a subtropical region. This study aims to investigate the association between typhoons and ADEs and their influences on the ambient particulate air quality, which might occur in East Asia. Four sites along the Kaoping River were selected to collect PM 10 with high-volume samplers during and after the ADE accompanying with Typhoon Doksuri on June 29, 2012. During the ADE, PM 10 concentration rose as high as 30-40 folds higher than those on regular days. Chemical composition of PM 10 was further analyzed to verify several valuable indicators including the molar ratios of [Cl -]/[Na + ] (0.95-1.02), the mass ratios of Fe/Cd (211.6-3957), and the mass ratios of OC/EC (1.18-1.35). Nevertheless, the chloride deficit phenomenon was not favorable during the ADE. Moreover, CMB receptor modeling results showed that aeolian dust and sea-salts were major contributors of PM 10 during the ADE. Along the Kaoping River, the contribution of aeolian dust to PM 10 ranged from 11.5 to 33.1% during the ADE, and reduced to 7.2-23.0% after the ADE. However, a small amount of finer aeolian dust could be still suspended in the ambient air after the ADE. Moreover, integrating SURFER software and WRF model was appropriate to locate the hot spots influenced by the ADE.