Constraints on instantaneous ozone production rates and regimes during DOMINO derived using in-situ OH reactivity measurements

Abstract. In this study air masses are characterized in terms of their total OH reactivity which is a robust measure of the "reactive air pollutant loading". The measurements were performed during the DOMINO campaign (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) held from 21/11/2008 to 08/12/2008 at the Atmospheric Sounding Station – El Arenosillo (37.1° N–6.7° W, 40 m a.s.l.). The site was frequently impacted by marine air masses (arriving at the site from the southerly sector) and air masses from the cities of Huelva (located NW of the site), Seville and Madrid (located NNE of the site). OH reactivity values showed strong wind sector dependence. North eastern "continental" air masses were characterized by the highest OH reactivities (average: 31.4 ± 4.5 s−1; range of average diel values: 21.3–40.5 s−1), followed by north western "industrial" air masses (average: 13.8 ± 4.4 s−1; range of average diel values: 7–23.4 s−1) and marine air masses (average: 6.3 ± 6.6 s−1; range of average diel values: below detection limit −21.7 s−1), respectively. The average OH reactivity for the entire campaign period was ~18 s−1 and no pronounced variation was discernible in the diel profiles with the exception of relatively high values from 09:00 to 11:00 UTC on occasions when air masses arrived from the north western and southern wind sectors. The measured OH reactivity was used to constrain both diel instantaneous ozone production potential rates and regimes. Gross ozone production rates at the site were generally limited by the availability of NOx with peak values of around 20 ppbV O3 h−1. Using the OH reactivity based approach, derived ozone production rates indicate that if NOx would no longer be the limiting factor in air masses arriving from the continental north eastern sector, peak ozone production rates could double. We suggest that the new combined approach of in-situ fast measurements of OH reactivity, nitrogen oxides and peroxy radicals for constraining instantaneous ozone production rates, could significantly improve analyses of upwind point sources and their impact on regional ozone levels.

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OH reactivity measurements in a coastal location in Southwestern Spain during DOMINO

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-12-4979-2012 ◽

2012 ◽

Vol 12 (2) ◽

pp. 4979-5014 ◽

Cited By ~ 7

Author(s):

V. Sinha ◽

J. Williams ◽

J. M. Diesch ◽

F. Drewnick ◽

M. Martinez ◽

...

Keyword(s):

Nitrogen Oxides ◽

Point Sources ◽

Air Pollutant ◽

Ozone Production ◽

Strong Wind ◽

Production Rates ◽

Air Masses ◽

North Eastern ◽

Marine Air ◽

North Western

Abstract. In this study air masses are characterized in terms of their total OH reactivity which is a robust measure of the "reactive air pollutant loading". The measurements were performed during the DOMINO campaign (Diel Oxidant Mechanisms In relation to Nitrogen Oxides) held from 21 November 2008 to 8 December 2008 at the Atmospheric Sounding Station – El Arenosillo (37.1° N–6.7° W, 40 m a.s.l.). The site was frequently impacted by marine air masses (arriving at the site from the southerly sector) and air masses from the cities of Huelva (located NW of the site), Seville and Madrid (located NNE of the site). OH reactivity values showed strong wind sector dependence. North eastern "continental" air masses were characterized by the highest OH reactivities (average: 31.4 ± 4.5 s−1; range of average diel values: 21.3–40.5 −1), followed by north western "industrial" air masses (average: 13.8 ± 4.4 s−1; range of average diel values: 7–23.4 s−1) and marine air masses (average: 6.3 ± 6.6 s−1; range of average diel values: below detection limit −21.7 s−1), respectively. The average OH reactivity for the entire campaign period was ~18 s−1 and no pronounced variation was discernible in the diel profiles with the exception of relatively high values from 09:00 to 11:00 UTC on occasions when air masses arrived from the north western and southern wind sectors. The measured OH reactivity was used to constrain both diel instantaneous ozone production potential rates and regimes. Gross ozone production rates at the site were generally limited by the availability of NOx with peak values of around 20 ppbV O3 h−1. Using the OH reactivity based approach, derived ozone production rates indicate that if NOx would no longer be the limiting factor in air masses arriving from the continental north eastern sector, peak ozone production rates could double. We suggest that the new combined approach of in-situ fast measurements of OH reactivity, nitrogen oxides and peroxy radicals for constraining instantaneous ozone production rates, could significantly improve analyses of upwind point sources and their impact on regional ozone levels.

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Diagnosis of Photochemical Ozone Production Rates and Limiting Factors in Continental Outflow Air Masses Reaching Fukue Island, Japan: Ozone-Control Implications

Aerosol and Air Quality Research ◽

10.4209/aaqr.2015.04.0220 ◽

2016 ◽

Vol 16 (2) ◽

pp. 430-441 ◽

Cited By ~ 9

Author(s):

Yugo Kanaya ◽

Hiroshi Tanimoto ◽

Yoko Yokouchi ◽

Fumikazu Taketani Fumikazu Taketani ◽

Yuichi Komazaki ◽

...

Keyword(s):

Ozone Production ◽

Limiting Factors ◽

Production Rates ◽

Air Masses ◽

Ozone Control ◽

Photochemical Ozone ◽

Continental Outflow

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Oxidation processes in the eastern Mediterranean atmosphere: evidence from the modelling of HO<sub><i>x</i></sub> measurements over Cyprus

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-10825-2018 ◽

2018 ◽

Vol 18 (14) ◽

pp. 10825-10847 ◽

Cited By ~ 9

Author(s):

Chinmay Mallik ◽

Laura Tomsche ◽

Efstratios Bourtsoukidis ◽

John N. Crowley ◽

Bettina Derstroff ◽

...

Keyword(s):

Eastern Mediterranean ◽

Early Morning ◽

Rate Coefficients ◽

Peroxy Radicals ◽

Air Masses ◽

Model Simulations ◽

Oxidation Processes ◽

The Mediterranean ◽

Marine Air

Abstract. The Mediterranean is a climatically sensitive region located at the crossroads of air masses from three continents: Europe, Africa, and Asia. The chemical processing of air masses over this region has implications not only for the air quality but also for the long-range transport of air pollution. To obtain a comprehensive understanding of oxidation processes over the Mediterranean, atmospheric concentrations of the hydroxyl radical (OH) and the hydroperoxyl radical (HO2) were measured during an intensive field campaign (CYprus PHotochemistry EXperiment, CYPHEX-2014) in the northwest of Cyprus in the summer of 2014. Very low local anthropogenic and biogenic emissions around the measurement location provided a vantage point to study the contrasts in atmospheric oxidation pathways under highly processed marine air masses and those influenced by relatively fresh emissions from mainland Europe.The CYPHEX measurements were used to evaluate OH and HO2 simulations using a photochemical box model (CAABA/MECCA) constrained with CYPHEX observations of O3, CO, NOx, hydrocarbons, peroxides, and other major HOx (OH + HO2) sources and sinks in a low-NOx environment (< 100 pptv of NO). The model simulations for OH agreed to within 10 % with in situ OH observations. Model simulations for HO2 agreed to within 17 % of the in situ observations. However, the model strongly under-predicted HO2 at high terpene concentrations, this under-prediction reaching up to 38 % at the highest terpene levels. Different schemes to improve the agreement between observed and modelled HO2, including changing the rate coefficients for the reactions of terpene-generated peroxy radicals (RO2) with NO and HO2 as well as the autoxidation of terpene-generated RO2 species, are explored in this work. The main source of OH in Cyprus was its primary production from O3 photolysis during the day and HONO photolysis during early morning. Recycling contributed about one-third of the total OH production, and the maximum recycling efficiency was about 0.7. CO, which was the largest OH sink, was also the largest HO2 source. The lowest HOx production and losses occurred when the air masses had higher residence time over the oceans.

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New determinations of tides on the north-western Ross Ice Shelf

Antarctic Science ◽

10.1017/s0954102020000498 ◽

2020 ◽

pp. 1-14

Author(s):

Richard D. Ray ◽

Kristine M. Larson ◽

Bruce J. Haines

Keyword(s):

Time Series ◽

Tide Gauge ◽

High Rate ◽

Ice Shelf ◽

Ross Ice Shelf ◽

The North ◽

Global Positioning ◽

North Western

Abstract New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2–3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

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A Review of Recently Discovered Remains of the Pleistocene Branchiopods (Anostraca, Notostraca) from NE Siberia and Arctic Canada

Water ◽

10.3390/w13030280 ◽

2021 ◽

Vol 13 (3) ◽

pp. 280

Author(s):

D. Christopher Rogers ◽

Anton A. Zharov ◽

Anna N. Neretina ◽

Svetlana A. Kuzmina ◽

Alexey A. Kotov

Keyword(s):

Western North America ◽

Temporary Wetlands ◽

Indicator Organisms ◽

Aquatic Habitats ◽

Eastern Asia ◽

Large Mammal ◽

Large Branchiopods ◽

North Eastern ◽

North Western ◽

Large Branchiopod

In this study, we examine, identify, and discuss fossil remains of large branchiopod crustaceans collected from six sites across the Beringian region (north-eastern Asia and north-western North America). Eggs and mandibles from Anostraca and Notostraca, as well as a notostracan telson fragment and a possible notostracan second maxilla, were collected from both paleosediment samples and also from large mammal hair. The remains of large branchiopods and other species that are limited to seasonally astatic aquatic habitats (temporary wetlands) could be useful indicator organisms of paleoecological conditions. Different recent large branchiopod species have very different ecological preferences, with each species limited to specific geochemical component tolerance ranges regarding various salinity, cation, and gypsum concentrations. Our purpose is to bring the potential usefulness of these common fossil organisms to the attention of paleoecologists.

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Airborne determination of the temporo-spatial distribution of benzene, toluene, nitrogen oxides and ozone in the boundary layer across Greater London, UK

Atmospheric Chemistry and Physics ◽

10.5194/acp-15-5083-2015 ◽

2015 ◽

Vol 15 (9) ◽

pp. 5083-5097 ◽

Cited By ~ 16

Author(s):

M. D. Shaw ◽

J. D. Lee ◽

B. Davison ◽

A. Vaughan ◽

R. M. Purvis ◽

...

Keyword(s):

Boundary Layer ◽

Nitrogen Oxides ◽

Linear Regression Analysis ◽

Proton Transfer Reaction ◽

Mixing Ratios ◽

Spatially Resolved ◽

Dual Channel ◽

Benzene Toluene

Abstract. Highly spatially resolved mixing ratios of benzene and toluene, nitrogen oxides (NOx) and ozone (O3) were measured in the atmospheric boundary layer above Greater London during the period 24 June to 9 July 2013 using a Dornier 228 aircraft. Toluene and benzene were determined in situ using a proton transfer reaction mass spectrometer (PTR-MS), NOx by dual-channel NOx chemiluminescence and O3 mixing ratios by UV absorption. Average mixing ratios observed over inner London at 360 ± 10 m a.g.l. were 0.20 ± 0.05, 0.28 ± 0.07, 13.2 ± 8.6, 21.0 ± 7.3 and 34.3 ± 15.2 ppbv for benzene, toluene, NO, NO2 and NOx respectively. Linear regression analysis between NO2, benzene and toluene mixing ratios yields a strong covariance, indicating that these compounds predominantly share the same or co-located sources within the city. Average mixing ratios measured at 360 ± 10 m a.g.l. over outer London were always lower than over inner London. Where traffic densities were highest, the toluene / benzene (T / B) concentration ratios were highest (average of 1.8 ± 0.5 ppbv ppbv-1), indicative of strong local sources. Daytime maxima in NOx, benzene and toluene mixing ratios were observed in the morning (~ 40 ppbv NOx, ~ 350 pptv toluene and ~ 200 pptv benzene) and in the mid-afternoon for ozone (~ 40 ppbv O3), all at 360 ± 10 m a.g.l.

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Cloud condensation nuclei as a real source of ice forming nuclei in continental and marine air masses

Atmospheric Research ◽

10.1016/0169-8095(95)00005-c ◽

1995 ◽

Vol 38 (1-4) ◽

pp. 351-359 ◽

Cited By ~ 16

Author(s):

J. Rosinski

Keyword(s):

Cloud Condensation Nuclei ◽

Condensation Nuclei ◽

Air Masses ◽

Marine Air

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Nine years of UV aerosol optical depth measurements at Thessaloniki, Greece

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-2091-2007 ◽

2007 ◽

Vol 7 (8) ◽

pp. 2091-2101 ◽

Cited By ~ 90

Author(s):

S. Kazadzis ◽

A. Bais ◽

V. Amiridis ◽

D. Balis ◽

C. Meleti ◽

...

Keyword(s):

Aerosol Optical Depth ◽

Optical Depth ◽

Back Trajectories ◽

Air Masses ◽

North Eastern ◽

Range Transport ◽

Air Quality Monitoring Stations ◽

Pm 10 ◽

The City

Abstract. Spectral measurements of the aerosol optical depth (AOD) and the Ångström coefficient were conducted at Thessaloniki, Greece (40.5° N, 22.9° E) between January 1997 and December 2005 with a Brewer MKIII double-monochromator spectroradiometer. The dataset was compared with collocated measurements of a second spectroradiometer (Brewer MKII) and a CIMEL sun-photometer, showing correlations of 0.93 and 0.98, respectively. A seasonal variation of the AOD was observed at Thessaloniki, with AOD values at 340 nm of 0.52 and 0.28 for August and December respectively. Back trajectories of air masses for up to 4 days were used to assess the influence of long-range transport from various regions to the aerosol load over Thessaloniki. It is shown that part of the observed seasonality can be attributed to air masses with high AOD originating from North-Eastern and Eastern directions during summertime. The analysis of the long-term record (9 years) of AOD showed a downward tendency. A similar decreasing tendency was found in the record of the PM$_{10}$ aerosol measurements, which are conducted near the surface at 4 air-quality monitoring stations in the area of the city of Thessaloniki.

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