Isoprene above the Eastern Mediterranean: Seasonal variation and contribution to the oxidation capacity of the atmosphere

Liakakou, Eleni; Vrekoussis, Mihalis; Bonsang, B.; Donousis, Ch.; Kanakidou, Maria; Mihalopoulos, N.

doi:10.1016/j.atmosenv.2006.09.034

Cited by 104 publications

(96 citation statements)

References 30 publications

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“…The median diel cycles of isoprene and the monoterpenes follow a roughly sinusoidal curve and were strongly light dependent. This finding is consistent with the literature concerning isoprene and monoterpene emissions and atmospheric mixing ratios in the Mediterranean area (Kesselmeier et al, 1998;Liakakou et al, 2007;Davison et al, 2009). Due to the light-dependent profiles, it was expected that isoprene levels would decrease to nearly zero at night, which is the case for the GC-MS signal (see Supplement S1, Fig.…”

Section: Biogenic Compoundssupporting

confidence: 83%

“…100 and 300 pptv respectively (Yassaa et al, 2012). The measured values in this study are consistent with levels reported previously from the Mediterranean areas (Liakakou et al, 2007;Davison et al, 2009). Comparable emission rates of isoprene and the sum of monoterpenes can be regarded as typical for the Mediterranean vegetation (Kesselmeier and Staudt, 1999).…”

Section: Biogenic Compoundssupporting

confidence: 81%

“…Moreover, it has been shown that the mixing ratios 1 http://data.worldbank.org/country/cyprus of many VOCs, especially OVOCs, in the Mediterranean strongly depend on long-distance transport and are periodically influenced by biomass burning (Salisbury et al, 2003;Holzinger et al, 2005). Reactive biogenic species such as isoprene have also been shown to be emitted from Mediterranean vegetation (Kesselmeier et al, 1996;Liakakou et al, 2007). To this end we have examined the behavior of an alcohol (methanol), a carbonyl (acetone) and an acid (acetic acid).…”

Section: Introductionmentioning

confidence: 99%

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Volatile organic compounds (VOCs) in photochemically aged air from the eastern and western Mediterranean

et al. 2017

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Abstract. During the summertime CYPHEX campaign (CYprus PHotochemical EXperiment 2014) in the eastern Mediterranean, multiple volatile organic compounds (VOCs) were measured from a 650 m hilltop site in western Cyprus (34 • 57 N/32 • 23 E). Periodic shifts in the northerly Etesian winds resulted in the site being alternately impacted by photochemically processed emissions from western (Spain, France, Italy) and eastern (Turkey, Greece) Europe. Furthermore, the site was situated within the residual layer/free troposphere during some nights which were characterized by high ozone and low relative humidity levels. In this study we examine the temporal variation of VOCs at the site. The sparse Mediterranean scrub vegetation generated diel cycles in the reactive biogenic hydrocarbon isoprene, from very low values at night to a diurnal median level of 80-100 pptv. In contrast, the oxygenated volatile organic compounds (OVOCs) methanol and acetone exhibited weak diel cycles and were approximately an order of magnitude higher in mixing ratio (ca. 2.5-3 ppbv median level by day, range: ca. 1-8 ppbv) than the locally emitted isoprene and aromatic compounds such as benzene and toluene. Acetic acid was present at mixing ratios between 0.05 and 4 ppbv with a median level of ca. 1.2 ppbv during the daytime. When data points directly affected by the residual layer/free troposphere were excluded, the acid followed a pronounced diel cycle, which was influenced by various local effects including photochemical production and loss, direct emission, dry deposition and scavenging from advecting air in fog banks. The Lagrangian model FLEXPART was used to determine transport patterns and photochemical processing times (between 12 h and several days) of air masses originating from eastern and western Europe. Ozone and many OVOC levels were ∼ 20 and ∼ 30-60 % higher, respectively, in air arriving from the east. Using the FLEXPART calculated transport time, the contribution of photochemical processing, sea surface contact and dilution was estimated. Methanol and acetone decreased with residence time in the marine boundary layer (MBL) with loss rate constants of 0.74 and 0.53 day −1 from eastern Europe and 0.70 and 0.34 day −1 from western Europe, respectively. Simulations using the EMAC model underestimate these loss rates. The missing sink in the calculation is most probably an oceanic uptake enhanced by microbial consumption of methanol and acetone, although the temporal and spatial variability in the source strength on the continents might play a role as well. Correlations between acetone and methanol were weaker in western air massesPublished by Copernicus Publications on behalf of the European Geosciences Union. = 0.68), but were stronger in air masses measured after the shorter transport time from the east (r 2 = 0.73).

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Section: Biogenic Compoundssupporting

confidence: 83%

Section: Biogenic Compoundssupporting

confidence: 81%

Section: Introductionmentioning

confidence: 99%

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Volatile organic compounds (VOCs) in photochemically aged air from the eastern and western Mediterranean

et al. 2017

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“…Several studies have shown that marine emissions of biogenic volatile organic compounds (BVOCs) and primary organic aerosols have the potential to affect coastal air quality (O'Dowd et al, 2004;Liakakou et al, 2007;Gantt et al, 2010). Observations of aerosol composition show that these emissions, which include both biogenic trace gases and parCorrespondence to: N. Meskhidze (nmeskhidze@ncsu.edu) ticles, are strongly tied to the seasonal cycles in ocean biology (O'Dowd et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

The contribution of marine organics to the air quality of the western United States

2010

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Abstract. The contribution of marine organic emissions to the air quality in coastal areas of the western United States is studied using the latest version of the US Environmental Protection Agency (EPA) regional-scale Community Multiscale Air Quality (CMAQv4.7) modeling system. Emissions of marine isoprene, monoterpenes, and primary organic matter (POM) from the ocean are implemented into the model to provide a comprehensive view of the connection between ocean biology and atmospheric chemistry and air pollution. Model simulations show that marine organics can increase the concentration of PM 2.5 by 0.1-0.3 µg m −3 (up to 5%) in some coastal cities such as San Francisco, CA. This increase in the PM 2.5 concentration is primarily attributed to the POM emissions, with small contributions from the marine isoprene and monoterpenes. When marine organic emissions are included, organic carbon (OC) concentrations over the remote ocean are increased by up to 50% (25% in coastal areas), values consistent with recent observational findings. This study is the first to quantify the air quality impacts from marine POM and monoterpenes for the United States, and it highlights the need for inclusion of marine organic emissions in air quality models.

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“…VOCs affect the formation of tropospheric ozone (Houwelling et al, 1998;Poisson et al, 2000), determine the oxidizing capacity of the atmosphere (Vrekoussis et al, 2004(Vrekoussis et al, , 2006Monks et al, 2005;Liakakou et al, 2007), contribute to the formation of secondary organic aerosols, SOA, (Kanakidou et al, 2005; and also to cloud condensation nuclei, CCN, production . In order to assess the significance of VOCs in controlling atmospheric chemistry it is important to improve our knowledge of the spatial distribution of their sources and their atmospheric removal.…”

Section: Introductionmentioning

confidence: 99%

GOME-2 observations of oxygenated VOCs: what can we learn from the ratio glyoxal to formaldehyde on a global scale?

et al. 2010

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Abstract. Collocated data sets of glyoxal (CHO.CHO) and formaldehyde (HCHO) were retrieved for the first time from measurements of the Global Ozone Monitoring Experiment-2 (GOME-2) during the first two years of operation in 2007 and 2008. Both oxygenated Volatile Organic Compounds, OVOC, are key intermediate species produced during the oxidation of precursor hydrocarbons. Their short lifetime of a few hours in the lower troposphere links them to emission sources and makes them useful tracers of photochemical activity. The global composite maps of GOME-2 HCHO and CHO.CHO have strong similarities confirming their common atmospheric and/or surface sources. The highest column amounts of these OVOCs are recorded over regions with enhance biogenic emissions (e.g. tropical forests in South America, Africa and Indonesia). Enhanced OVOC values are also present over areas of anthropogenic activity and biomass burning (e.g. over China, N. America, Europe and Australia). The ratio of CHO.CHO to HCHO, R GF , has been used, for the first time on a global scale, to classify the sources according to biogenic and/or anthropogenic emissions of the precursors; R GF between 0.040 to 0.060 point to the existence of biogenic emissions with the highest values being observed at the highest Enhanced Vegetation Index, EVI. R GF s below 0.040 are indicative of anthropogenic emissions and associated with high levels of NO 2 . This decreasing tendency of R GF with increasing NO 2 is also observed when analyzing data for individual large cities, indicating that it is a common feature. The results obtained for R GF from GOME-2 data are compared with the findings based on regional SCIA-MACHY observations showing good agreement. This is exCorrespondence to: M. Vrekoussis (vrekoussis@iup.physik.uni-bremen.de) plained by the excellent correlation of the global retrieved column amounts of CHO.CHO and HCHO from the GOME-2 and SCIAMACHY instruments for the period 2007-2008.

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Isoprene above the Eastern Mediterranean: Seasonal variation and contribution to the oxidation capacity of the atmosphere

Cited by 104 publications

References 30 publications

Volatile organic compounds (VOCs) in photochemically aged air from the eastern and western Mediterranean

Volatile organic compounds (VOCs) in photochemically aged air from the eastern and western Mediterranean

The contribution of marine organics to the air quality of the western United States

GOME-2 observations of oxygenated VOCs: what can we learn from the ratio glyoxal to formaldehyde on a global scale?

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