Significant formation of water-insoluble secondary organic aerosols in semi-arid urban environment - Archive ouverte HAL
Article Dans Une Revue Geophysical Research Letters Année : 2008

Significant formation of water-insoluble secondary organic aerosols in semi-arid urban environment

Résumé

Diurnal variations of submicron elemental carbon (EC), water-soluble organic carbon (WSOC) and water-insoluble organic carbon (WIOC) were investigated at an urban background site in Cairo (Egypt) from 23 March to 14 April 2005. Well-marked diurnal patterns, with minima during the traffic-influenced morning period (6:00-9:00) and maxima during the intense photochemical period (12:00-15:00), were observed for the WSOC/EC ratio and, more surprisingly, for the WIOC/EC ratio. Such diurnal variations suggest significant formation of both water-soluble and waterinsoluble secondary organic aerosols during the afternoon. Applying the EC-tracer method, freshly-formed secondary organic carbon (fresh SOC) was found to possibly account for more than 50% of OC concentrations measured during the 12:00-15:00 period, and this fresh SOC was calculated to be mainly ($60%) composed of water-insoluble species. The latter (unexpected) result could be due to low ambient relative humidity as well as to the importance of anthropogenic volatile organic compounds in Cairo.
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Dates et versions

hal-03192780 , version 1 (09-04-2021)

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Olivier Favez, Jean Sciare, Hélène Cachier, Stéphane Alfaro, Magdy Abdelwahab. Significant formation of water-insoluble secondary organic aerosols in semi-arid urban environment. Geophysical Research Letters, 2008, 35 (15), pp.L15801. ⟨10.1029/2008GL034446⟩. ⟨hal-03192780⟩

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