Tropospheric Reaction Chemistry

Akimoto, Hajime

doi:10.1007/978-4-431-55870-5_7

Cited by 3 publications

(5 citation statements)

References 260 publications

(281 reference statements)

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“…At the same time, ozone is depleted by the NO emissions in the fresh ship plumes (NO + O 3 → NO 2 + O 2 , Sillman, 1999). This effect is seen when an emission source co-emitting NO x and VOCs is very close (Akimoto, 2016), as ozone values recover rapidly downwind through NO 2 photolysis and mixing. The ozone titration effect has similarly been observed in negative ozone-CO correlations (Parrish et al, 1998).…”

Section: Oh Reactivity/ozone Correlationsmentioning

confidence: 99%

“…As a secondary pollutant and being suppressed by NO, ozone can often be elevated at a distance from the pollution sources (Sudo and Akimoto, 2007). Large quantities of ozone can be produced during long-range transport under sunlight influence (Parrish et al, 1998;Akimoto, 2016;Moradzadeh et al, 2019). Consequently, in the seaways around the Arabian Peninsula, ozone mixing ratios were mostly between 50 and 80 ppb, which is the range of daytime values in polluted Beijing (Williams et al, 2016;Yang et al, 2017).…”

Section: Oh Reactivity/ozone Correlationsmentioning

confidence: 99%

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Shipborne measurements of total OH reactivity around the Arabian Peninsula and its role in ozone chemistry

et al. 2019

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Abstract. The Arabian Peninsula is characterized by high and increasing levels of photochemical air pollution. Strong solar irradiation, high temperatures and large anthropogenic emissions of reactive trace gases result in intense photochemical activity, especially during the summer months. However, air chemistry measurements in the region are scarce. In order to assess regional pollution sources and oxidation rates, the first ship-based direct measurements of total OH reactivity were performed in summer 2017 from a vessel traveling around the peninsula during the AQABA (Air Quality and Climate Change in the Arabian Basin) campaign. Total OH reactivity is the total loss frequency of OH radicals due to all reactive compounds present in air and defines the local lifetime of OH, the most important oxidant in the troposphere. During the AQABA campaign, the total OH reactivity ranged from below the detection limit (5.4 s−1) over the northwestern Indian Ocean (Arabian Sea) to a maximum of 32.8±9.6 s−1 over the Arabian Gulf (also known as Persian Gulf) when air originated from large petroleum extraction/processing facilities in Iraq and Kuwait. In the polluted marine regions, OH reactivity was broadly comparable to highly populated urban centers in intensity and composition. The permanent influence of heavy maritime traffic over the seaways of the Red Sea, Gulf of Aden and Gulf of Oman resulted in median OH sinks of 7.9–8.5 s−1. Due to the rapid oxidation of direct volatile organic compound (VOC) emissions, oxygenated volatile organic compounds (OVOCs) were observed to be the main contributor to OH reactivity around the Arabian Peninsula (9 %–35 % by region). Over the Arabian Gulf, alkanes and alkenes from the petroleum extraction and processing industry were an important OH sink with ∼9 % of total OH reactivity each, whereas NOx and aromatic hydrocarbons (∼10 % each) played a larger role in the Suez Canal, which is influenced more by ship traffic and urban emissions. We investigated the number and identity of chemical species necessary to explain the total OH sink. Taking into account ∼100 individually measured chemical species, the observed total OH reactivity can typically be accounted for within the measurement uncertainty (50 %), with 10 dominant trace gases accounting for 20 %–39 % of regional total OH reactivity. The chemical regimes causing the intense ozone pollution around the Arabian Peninsula were investigated using total OH reactivity measurements. Ozone vs. OH reactivity relationships were found to be a useful tool for differentiating between ozone titration in fresh emissions and photochemically aged air masses. Our results show that the ratio of NOx- and VOC-attributed OH reactivity was favorable for ozone formation almost all around the Arabian Peninsula, which is due to NOx and VOCs from ship exhausts and, often, oil/gas production. Therewith, total OH reactivity measurements help to elucidate the chemical processes underlying the extreme tropospheric ozone concentrations observed in summer over the Arabian Basin.

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Section: Oh Reactivity/ozone Correlationsmentioning

confidence: 99%

Section: Oh Reactivity/ozone Correlationsmentioning

confidence: 99%

Shipborne measurements of total OH reactivity around the Arabian Peninsula and its role in ozone chemistry

et al. 2019

View full text Add to dashboard Cite

show abstract

“…At the same time, ozone is 5 depleted by the NO emissions in the fresh ship plumes (NO + O 3 → NO 2 + O 2 , Sillman, 1999). This effect is seen when an emission source co-emitting NO x and VOCs is very close (Akimoto, 2016), as ozone values recover rapidly downwind through NO 2 photolysis and mixing. The ozone titration effect has similarly been observed in negative ozone-CO correlations (Parrish et al, 1998).…”

Section: Oh Reactivity/ozone Correlations 30mentioning

confidence: 99%

“…As a secondary pollutant and being suppressed by NO, ozone can often be elevated at distance to the pollution sources (Sudo and Akimoto, 2007). Large quantities of ozone can be produced during long-range transport under sunlight influence (Parrish et al, 1998;Akimoto, 2016;Moradzadeh et al, 2019). Consequently, in the 15 seaways around the Arabian Peninsula, ozone mixing ratios were mostly between 50 and 80 ppb, which is the range of daytime values in polluted Beijing (Williams et al, 2016;Yang et al, 2017).…”

Section: Oh Reactivity/ozone Correlations 30mentioning

confidence: 99%

Shipborne measurements of total OH reactivity around the Arabian Peninsula and its role in ozone chemistry

Pfannerstill¹,

Wang²,

Edtbauer³

et al. 2019

Preprint

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The Arabian Peninsula is characterized by high and increasing levels of photochemical air pollution. Strong solar irradiation, high temperatures and large anthropogenic emissions of reactive trace gases result in intense photochemical activity, especially during the summer months. However, air chemistry measurements in the region are scarce. In order to assess regional pollution sources and oxidation rates, the first ship-based direct measurements of total OH reactivity were 15 performed in summer 2017 from a vessel travelling around the peninsula during the AQABA (Air Quality and Climate Change in the Arabian Basin) campaign. Total OH reactivity is the total loss frequency of OH radicals due to all reactive compounds present in air and defines the local lifetime of OH, the most important oxidant in the troposphere. During the AQABA campaign, the total OH reactivity ranged from below the detection limit (5.4 s -1 ) over the north-western Indian Ocean (Arabian Sea) to a maximum of 32.8 ± 9.6 s -1 over the Arabian Gulf (also known as Persian Gulf) when air originated 20 from large petroleum extraction/processing facilities in Iraq and Kuwait. In the polluted marine regions, OH reactivity was broadly comparable to highly populated urban centers in intensity and composition. The permanent influence of heavy maritime traffic over the seaways of the Red Sea, Gulf of Aden and Gulf of Oman resulted in median OH sinks of 7.9−8.5 s -1 . Due to the rapid oxidation of direct volatile organic compound (VOC) emissions, oxygenated volatile organic compounds (OVOCs) were observed to be the main contributor to OH reactivity around the Arabian Peninsula (9−35 % by 25 region). Over the Arabian Gulf, alkanes and alkenes from the petroleum extraction and processing industry were an important OH sink with ~9 % of total OH reactivity each, whereas NO x and aromatic hydrocarbons (~10 % each) played a larger role in the Suez Canal, which is influenced more by ship traffic and urban emissions. We investigated the number and identity of chemical species necessary to explain the total OH sink. Taking into account ~100 individually measured chemical species, the observed total OH reactivity can typically be accounted for within the measurement uncertainty, with 30 10 dominant trace gases accounting for 20−39 % of regional total OH reactivity. The chemical regimes causing the intense ozone pollution around the Arabian Peninsula were investigated using total OH reactivity measurements. Ozone vs. OH reactivity relationships were found to be a useful tool for differentiating between ozone titration in fresh emissions and https://doi.photochemically aged air masses. Our results show that the ratio of NO x -and VOC-attributed OH reactivity was favorable for ozone formation almost all around the Arabian Peninsula, which is due to NO x and VOCs from ship exhausts and, often, oil/gas production. Therewith, total OH reactivity measurements help to elucidate the chemical processes underlying the extreme tropospheric ozone concentrations observed in sum...

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“…In these latitudes, O 3 concentrations have rised at the annual rate of 0.5%-2% due to increasing emissions of O 3 precursors, i.e. nitrogen oxides (NO x ) and volatile organic compounds (VOCs) in the atmosphere (Vingarzan 2004;The Royal Society 2008;Akimoto 2016). In the future, O 3 concentrations will mainly depend on the emissions of O 3 precursors and climate scenarios (The Royal Society 2008; Sicard et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Elevated temperature and ozone modify structural characteristics of silver birch (Betula pendula) leaves

et al. 2019

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To study the effects of slightly elevated temperature and ozone (O3) on leaf structural characteristics of silver birch (Betula pendula Roth), saplings of four clonal genotypes of this species were exposed to elevated temperature (ambient air temperature +0.8–1.0 °C) and elevated O3 (1.3–1.4× ambient O3), alone and in combination, in an open-air exposure field over two growing seasons (2007 and 2008). So far, the impacts of moderate elevation of temperature or the combination of elevated temperature and O3 on leaf structure of silver birch have not been intensively studied, thus showing the urgent need for this type of studies. Elevated temperature significantly increased leaf size, reduced non-glandular trichome density, decreased epidermis thickness and increased plastoglobuli size in birch leaves during one or both growing seasons. During the second growing season, O3 elevation reduced leaf size, increased palisade layer thickness and decreased the number of plastoglobuli in spongy cells. Certain leaf structural changes observed under a single treatment of elevated temperature or O3, such as increase in the amount of chloroplasts or vacuole, were no longer detected at the combined treatment. Leaf structural responses to O3 and rising temperature may also depend on timing of the exposure during the plant and leaf development as indicated by the distinct changes in leaf structure along the experiment. Genotype-dependent cellular responses to the treatments were detected particularly in the palisade cells. Overall, this study showed that even a slight but realistic elevation in ambient temperature can notably modify leaf structure of silver birch saplings. Leaf structure, in turn, influences leaf function, thus potentially affecting acclimation capacity under changing climate.

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Tropospheric Reaction Chemistry

Cited by 3 publications

References 260 publications

Shipborne measurements of total OH reactivity around the Arabian Peninsula and its role in ozone chemistry

Shipborne measurements of total OH reactivity around the Arabian Peninsula and its role in ozone chemistry

Shipborne measurements of total OH reactivity around the Arabian Peninsula and its role in ozone chemistry

Elevated temperature and ozone modify structural characteristics of silver birch (Betula pendula) leaves

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