Processing of aerosol particles within the Habshan pollution plume. Issue 5 (13th March 2015)

• Record Type: Journal Article
• Authors: Semeniuk, T. A.; Bruintjes, R.; Salazar, V.; Breed, D.; Jensen, T.; Buseck, P. R.
• Is Part Of: Journal of geophysical research. Volume 120:Issue 5(2015:Mar.)
• Page Start: 1996
• Page End: 2012
• Publication Date: 2015-03-13
• Subjects: mineral dust -- pollution -- internally mixed particle -- coated particle -- TEM study -- heterogeneous reactions; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2014JD022279
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: The Habshan industrial site in the United Arab Emirates produces a regional‐scale pollution plume associated with oil and gas processing, discharging high loadings of sulfates and chlorides into the atmosphere, which interact with the ambient aerosol population. Aerosol particles and trace gas chemistry at this site were studied on two flights in the summer of 2002. Measurements were collected along vertical plume profiles to show changes associated with atmospheric processing of particle and gas components. Close to the outlet stack, particle concentrations were over 10, 000 cm −3, dropping to <2000 cm −3 in more dilute plume around 1500 m above the stack. Particles collected close to the stack and within the dilute plume were individually measured for size, morphology, composition, and mixing state using transmission electron microscopy coupled with energy‐dispersive X‐ray spectroscopy. Close to the stack, most coarse particles consisted of mineral dust and NaCl crystals from burning oil brines, while sulfate droplets dominated the fine mode. In more dilute plume, at least 1500 m above the stack, the particle spectrum was more diverse, with a significant increase in internally mixed particle types. Dilute plume samples consisted of coarse NaCl/silicate aggregates or NaCl‐rich droplets, often with a sulfate component, while fine‐fraction particles were of mixed cation sulfates, also internally mixed with nanospherical soot or silicates. Thus, both chloride and sulfate components of the pollution plume rapidly reacted with ambient mineral dust to form coated and aggregate particles, enhancing particle size, hygroscopicity, and reactivity of the coarse mode. The fine‐fraction sulfate‐bearing particles formed in the plume contribute to regional transport of sulfates, while coarse sulfate‐bearing fractions locally reduced the SO2 loading through sedimentation. The chloride‐ and sulfate‐bearing internally mixed particles formed in the plume markedly changed the reflectivity and scattering properties of the ambient aerosol population, as well as its hygroscopic and ice nucleation properties. Key Points: Documents formation and aging of diverse internally mixed particles in the plume Uptake of non‐sea salts changes hygroscopic properties of ambient particles Uptake of sulfates changes aerosol properties, affecting regional sulfate load