Shipborne measurements of ClNO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; in the Mediterranean Sea and around the Arabian Peninsula during summer

Eger, Philipp; Friedrich, Nils; Schuladen, Jan; Shenolikar, Justin; Fischer, H.; Tadić, Ivan; Harder, Hartwig; Martínez, Mònica; Rohloff, Roland; Tauer, Sebastian; Drewnick, Frank; Fachinger, Friederike; Brooks, James; Darbyshire, Eoghan; Sciare, Jean; Pikridas, Michael; Lelieveld, Jos; Crowley, John N.

doi:10.5194/acp-19-12121-2019

Cited by 25 publications

(24 citation statements)

References 75 publications

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“…also reported measurements of ClNO 2 in Leicester with a maximum value of 274 pptv in spring, 74.2 pptv in summer, and 248 pptv in winter, with a peak value at Penlee Point of 922 pptv. CMAQ predicted a maximum of 274 pptv in Leicester and 319 pptv at Penlee Point Eger et al (2019). conducted shipborne observations of ClNO 2 in the Mediterranean Sea and reported up to 600 pptv ClNO 2 during their campaign, which is similar to the prediction of the present study.…”

supporting

confidence: 89%

Impact of halogen chemistry on summertime air quality in coastal and continental Europe: application of the CMAQ model and implications for regulation

Borge

Sarwar

et al. 2019

Atmos. Chem. Phys.

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Abstract. Halogen (Cl, Br, and I) chemistry has been reported to influence the formation of secondary air pollutants. Previous studies mostly focused on the impact of chlorine species on air quality over large spatial scales. Very little attention has been paid to the effect of the combined halogen chemistry on air quality over Europe and its implications for control policy. In the present study, we apply a widely used regional model, the Community Multiscale Air Quality Modeling System (CMAQ), incorporated with the latest halogen sources and chemistry, to simulate the abundance of halogen species over Europe and to examine the role of halogens in the formation of secondary air pollution. The results suggest that the CMAQ model is able to reproduce the level of O3, NO2, and halogen species over Europe. Chlorine chemistry slightly increases the levels of OH, HO2, NO3, O3, and NO2 and substantially enhances the level of the Cl radical. Combined halogen chemistry induces complex effects on OH (ranging from −0.023 to 0.030 pptv) and HO2 (in the range of −3.7 to 0.73 pptv), significantly reduces the concentrations of NO3 (as much as 20 pptv) and O3 (as much as 10 ppbv), and decreases NO2 in highly polluted regions (as much as 1.7 ppbv); it increases NO2 (up to 0.20 ppbv) in other areas. The maximum effects of halogen chemistry occur over oceanic and coastal regions, but some noticeable impacts also occur over continental Europe. Halogen chemistry affects the number of days exceeding the European Union target threshold for the protection of human beings and vegetation from ambient O3. In light of the significant impact of halogen chemistry on air quality, we recommend that halogen chemistry be considered for inclusion in air quality policy assessments, particularly in coastal cities.

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supporting

confidence: 89%

Impact of halogen chemistry on summertime air quality in coastal and continental Europe: application of the CMAQ model and implications for regulation

Borge

Sarwar

et al. 2019

Atmos. Chem. Phys.

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“…In total, 20,000 km of the marine route was covered with an average speed of 3.4 ± 1.8 m s −1 over the course of 60 days. Further information on the AQABA ship campaign can be found elsewhere in the literature 16,17,57 .…”

Section: Methodsmentioning

confidence: 99%

The Red Sea Deep Water is a potent source of atmospheric ethane and propane

et al. 2020

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Non-methane hydrocarbons (NMHCs) such as ethane and propane are significant atmospheric pollutants and precursors of tropospheric ozone, while the Middle East is a global emission hotspot due to extensive oil and gas production. Here we compare in situ hydrocarbon measurements, performed around the Arabian Peninsula, with global model simulations that include current emission inventories (EDGAR) and state-of-the-art atmospheric circulation and chemistry mechanisms (EMAC model). While measurements of high mixing ratios over the Arabian Gulf are adequately simulated, strong underprediction by the model was found over the northern Red Sea. By examining the individual sources in the model and by utilizing air mass back-trajectory investigations and Positive Matrix Factorization (PMF) analysis, we deduce that Red Sea Deep Water (RSDW) is an unexpected, potent source of atmospheric NMHCs. This overlooked underwater source is comparable with total anthropogenic emissions from entire Middle Eastern countries, and significantly impacts the regional atmospheric chemistry.

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“…to high night-time temperatures and high reactivity of NO3 which reduce the interaction of N2O5 with chloride containing particles (Eger et al, 2019a). Elevated HONO mixing ratios (up to 0.3 ppbv) were observed in regions M3 and M6 where its contribution to NOz was 3.8 % and 4.2 %, respectively.…”

Section: Nozmentioning

confidence: 97%

Comment on acp-2021-42

2021

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We present ship-borne measurements of NOx (≡ NO + NO2) and NOy (≡ NOx + gas-and particle-phase organic and inorganic oxides of nitrogen) in summer 2017 as part of the expedition "Air Quality and climate change in the Arabian Basin" (AQABA). The NOx and NOz (≡ NOy -NOx) measurements, made with a thermal dissociation cavity-ringdown-spectrometer (TD-CRDS), were used to examine the chemical mechanisms involved in the processing of primary NOx emissions and their influence on the NOy budget in chemically distinct marine environments, including the Mediterranean Sea, the Red Sea, and the Arabian Gulf which were influenced to varying extents by emissions from shipping and oil and gas production. In all regions, we find that NOx is strongly connected to ship emissions, both via direct emission of NO and via the formation of HONO and its subsequent photolytic conversion to NO. Mean NO2 lifetimes were 3.9 hours in the Mediterranean Sea, 4.0 hours in the Arabian Gulf and 5.0 hours in the Red Sea area. The cumulative loss of NO2 during the night (reaction with O3) was more important than daytime losses (reaction with OH) over the Arabian Gulf (by a factor 2.8) and over the Red Sea (factor 2.9), whereas over the Mediterranean Sea, where OH levels were high, daytime losses dominated (factor 2.5). Regional ozone production efficiencies (OPE) ranged from 10.5 ± 0.9 to 19.1 ± 1.1. This metric quantifies the relative strength of photochemical O3 production from NOx, compared to the competing sequestering into NOz species. The largest values were found over the Arabian Gulf, consistent with high levels of O3 found in that region (10 -90 percentiles range: 23-108 ppbv).The fractional contribution of individual NOz species to NOy exhibited a large regional variability, with HNO3 generally the dominant component (on average 33 % of NOy) with significant contributions from organic nitrates (11 %) and particulate nitrates in the PM1 size range (8 %).

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Shipborne measurements of ClNO<sub>2</sub> in the Mediterranean Sea and around the Arabian Peninsula during summer

Cited by 25 publications

References 75 publications

Impact of halogen chemistry on summertime air quality in coastal and continental Europe: application of the CMAQ model and implications for regulation

Impact of halogen chemistry on summertime air quality in coastal and continental Europe: application of the CMAQ model and implications for regulation

The Red Sea Deep Water is a potent source of atmospheric ethane and propane

Comment on acp-2021-42

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