scholarly journals The influence of African air pollution on regional and global tropospheric chemistry

2006 ◽  
Vol 6 (4) ◽  
pp. 5797-5838 ◽  
Author(s):  
A. M. Aghedo ◽  
M. G. Schultz ◽  
S. Rast
Keyword(s):  
Biomass Burning ◽  
Ozone Concentration ◽  
Tropospheric Ozone ◽  
Surface Ozone ◽  
The United States ◽  
Tropospheric Chemistry ◽  
Anthropogenic Emissions ◽  
African Region ◽  
Biogenic Voc ◽  
Surface Ozone Concentration

Abstract. We investigate the relative importance of African biomass burning, biogenic volatile organic compounds (VOC), lightning and anthropogenic emissions to the tropospheric ozone budget over Africa and globally using a coupled global chemistry climate model. Our model studies indicate that the photochemical surface ozone concentration may rise by up to 50 ppbv in the burning region during the biomass burning seasons. Biogenic VOCs contribute between 5–20 ppbv to the near surface ozone concentration over the tropical African region. The impact of lightning on surface ozone is negligible, while anthropogenic emissions contribute a maximum of 10 ppbv to the surface ozone over Nigeria, South-Africa and Egypt. The annual average of the surface and column ozone over Africa shows that biomass burning is the single most important emission source affecting the African region, while biogenic emissions have the highest contribution during the rainy seasons. The contributions of African emissions to global tropospheric ozone burden (TOB) are about 9 Tg, 13 Tg, 8 Tg and 4 Tg for African biomass burning, biogenic VOC, lightning and anthropogenic emissions respectively. These correspond to 2.4%, 3.4%, 2.1% and 1% of the global tropospheric ozone budget respectively. Over Africa itself, the contribution of each of these emission types is only 2.4 Tg, 2.2 Tg, 1.4 Tg and 0.8 Tg respectively. Outside the continent, African biogenic VOC emissions yield the highest contribution to the TOB. Our model calculations suggest that about 70% of the tropospheric ozone produced from emissions in Africa is found outside the continent, thus exerting a noticeable influence on a large part of the tropical troposphere. Latin America experiences the highest impact of African emissions, followed by southeast and south-central Asia, Oceania, and the Middle East for all the emission categories; while Canada, the United States, Russia, Mongolia, China and Europe experience the least impact of African emissions.

scholarly journals The influence of African air pollution on regional and global tropospheric ozone

2007 ◽  
Vol 7 (5) ◽  
pp. 1193-1212 ◽  
Author(s):  
A. M. Aghedo ◽  
M. G. Schultz ◽  
S. Rast
Keyword(s):  
Central Asia ◽  
Biomass Burning ◽  
Ozone Concentration ◽  
Tropospheric Ozone ◽  
Surface Ozone ◽  
The United States ◽  
Biogenic Emissions ◽  
Anthropogenic Emissions ◽  
The Impact ◽  
Surface Ozone Concentration

Abstract. We investigate the influence of African biomass burning, biogenic, lightning and anthropogenic emissions on the tropospheric ozone over Africa and globally using a coupled global chemistry climate model. Our model studies indicate that surface ozone concentration may rise by up to 50 ppbv in the burning region during the biomass burning seasons. Biogenic emissions yield between 5–30 ppbv increase in the near surface ozone concentration over tropical Africa. The impact of lightning on surface ozone is negligible, while anthropogenic emissions yield a maximum of 7 ppbv increase in the annual-mean surface ozone concentration over Nigeria, South Africa and Egypt. Our results show that biogenic emissions are the most important African emission source affecting total tropospheric ozone. The influence of each of the African emissions on the global tropospheric ozone burden (TOB) of 384 Tg yields about 9.5 Tg, 19.6 Tg, 9.0 Tg and 4.7 Tg for biomass burning, biogenic, lightning and anthropogenic emissions emitted in Africa respectively. The impact of each of these emission categories on African TOB of 33 Tg is 2.5 Tg, 4.1 Tg, 1.75 Tg and 0.89 Tg respectively, which together represents about 28% of the total TOB calculated over Africa. Our model calculations also suggest that more than 70% of the tropospheric ozone produced by each of the African emissions is found outside the continent, thus exerting a noticeable influence on a large part of the tropical troposphere. Apart from the Atlantic and Indian Ocean, Latin America experiences the largest impact of African emissions, followed by Oceania, the Middle East, Southeast and south-central Asia, northern North America (i.e. the United States and Canada), Europe and north-central Asia, for all the emission categories.

Variation of the surface ozone concentration during precipitation

2020 ◽  
Author(s):  
Igor V. Ptashnik ◽  
Boris D. Belan ◽  
Denis E. Savkin ◽  
Gennadii N. Tolmachev ◽  
Tatayana K. Sklyadneva ◽  
...  
Keyword(s):  
Diurnal Variation ◽  
Ozone Concentration ◽  
Tropospheric Ozone ◽  
Surface Ozone ◽  
Chem Phys ◽  
Global Scale ◽  
Washington Dc ◽  
American Geophysical ◽  
The Impact ◽  
Surface Ozone Concentration

<p>In the review compiled by Monks et al. (2015), it is noted that the main variations in the tropospheric ozone are determined by the exchange between the troposphere and the stratosphere, in-situ photochemical production from gaseous precursors depending on their composition and concentration, solar radiation income, and meteorological conditions. The impact of precipitation on the surface ozone concentration is a less well-studied factor.</p><p>The process of ozone interaction with precipitation was studied theoretically (Heicklen, 1982). Two ways of the above process were analyzed: adsorption of gas molecules on the surface of a particle and a chemical reaction with its surface. There are no direct data on the verification of these findings in the literature. At the same time, there is some evidence of a possible link between precipitation and ozone.</p><p>This study is aimed to analyze the presence or absence of changes in the ozone concentration during precipitation. Variations of the surface ozone concentration (SOC) in the presence of precipitation were analyzed using the long-term data obtained at the TOR-station established in 1992 for ozone monitoring in Tomsk. It was revealed that these changes can be both positive (increase in concentration) and negative. The sharp changes in the SOC are observed when frontal precipitation takes place. In the presence of air-mass precipitation, the sign and magnitude of the change is determined by the diurnal variation of ozone concentration.</p><p>The analysis showed a coincidence of the SOC growth during precipitation with its increase in diurnal variation in 59% of cases. The coincidence in the wave of the concentration decline in the diurnal variation with decreasing precipitation rate is even higher and amounts to 85%.</p><p>Airborne sounding carried out in the vicinity of the TOR-station shown that in a number of cases the ozone deposition from the boundary layer is observed upon the transition of thermal stratification during the precipitation to neutral.</p><p> </p><p>Monks P. S, Archibald A. T., Colette A., Cooper O., Coyle M., Derwent R., Fowler D., Granier C., Law K. S., Mills G. E., Stevenson D. S., Tarasova O., Thouret V., von Schneidemesser E., Sommariva R., Wild O., Williams M. L. Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer. Atmos. Chem. Phys., 2015, v.15, N15, p.8889–8973.</p><p>Heicklen J. The Removal of Atmospheric Gases by Particulate Matter. In Heterogeneous Atmospheric Chemistry, ed. D. R. Schryer, Geophysical Monograph 26. American Geophysical Union, Washington, DC, USA, 1982, p. 93-98.</p>

scholarly journals TOAST 1.0: Tropospheric Ozone Attribution of Sources with Tagging for CESM 1.2.2

2018 ◽  
Author(s):  
Tim Butler ◽  
Aurelia Lupascu ◽  
Jane Coates ◽  
Shuai Zhu
Keyword(s):  
Tropospheric Ozone ◽  
Surface Ozone ◽  
Chemical Mechanism ◽  
System Model ◽  
Ozone Production ◽  
Anthropogenic Emissions ◽  
Source Attribution ◽  
Biogenic Voc ◽  
Community Earth System Model ◽  
Northern Hemispheric

Abstract. A system for source attribution of tropospheric ozone produced from both NOx and VOC precursors is described, along with its implementation in the Community Earth System Model (CESM) version 1.2.2 using CAM4. The user can specify an arbitrary number of tag identities for each NOx or VOC species in the model, and the tagging system rewrites the model chemical mechanism and source code to incorporate tagged tracers and reactions representing these tagged species, as well as ozone produced in the stratosphere. If the user supplies emission files for the corresponding tagged tracers, the model will produce tagged ozone tracers which represent the contribution of each of the tag identities to the modelled total tropospheric ozone. Our tagged tracers preserve Ox. The size of the tagged chemical mechanism scales linearly with the number of specified tag identities. Separate simulations are required for NOx and VOC tagging, which avoids the sharing of tag identities between NOx and VOC species. Results are presented and evaluated for both NOx and VOC source attribution. We show that northern hemispheric surface ozone is dominated year-round by anthropogenic emissions of NOx, but that the mix of corresponding VOC precursors changes over the course of the year; anthropogenic VOC emissions contribute significantly to surface ozone in winter-spring, while biogenic VOC are more important in summer. The system described here can provide important diagnostic information about modelled ozone production, and could be used to construct source-receptor relationships for tropospheric ozone.

scholarly journals Long-term trends of surface ozone and its influencing factors at the Mt. Waliguan GAW station, China – Part 1: Overall trends and characteristics

2015 ◽  
Vol 15 (21) ◽  
pp. 30987-31024 ◽  
Author(s):  
W. Y. Xu ◽  
W. L. Lin ◽  
X. B. Xu ◽  
J. Tang ◽  
J. Q. Huang ◽  
...  
Keyword(s):  
Ozone Concentration ◽  
Diurnal Cycle ◽  
Tropospheric Ozone ◽  
Surface Ozone ◽  
Three Dimensional ◽  
Western China ◽  
Long Term Trends ◽  
Increasing Trends ◽  
Surface Ozone Concentration

Abstract. Tropospheric ozone is an important atmospheric oxidant, greenhouse gas and atmospheric pollutant at the same time. The level of tropospheric ozone, particularly in the surface layer, is impacted by emissions of precursors and is subjected to meteorological conditions. Due its importance, the long-term variation trend of baseline ozone is highly needed for environmental and climate change assessment. So far, studies about the long-term trends of ozone at representative sites are mainly available for European and North American sites. Similar studies are lacking for China, a country with rapid economic growth for recent decades, and many other developing countries. To uncover the long-term characteristics and trends of baseline surface ozone, concentration in western China, measurements at a global baseline Global Atmospheric Watch (GAW) station in the north-eastern Tibetan Plateau region (Mt. Waliguan) for the period of 1994 to 2013 were analysed in this study, using a modified Mann–Kendall test and the Hilbert–Huang Transform analysis for the trend and periodicity analysis, respectively. Results reveal higher surface ozone during the night and lower during the day at Waliguan, due to mountain-valley breezes. A seasonal maximum in summer was found, which was probably caused by enhanced stratosphere-to-troposphere exchange events and/or by tropospheric photochemistry. Analysis suggests that there is a season-diurnal cycle in the three-dimensional winds on top of Mt. Waliguan. Season-dependent daytime and nighttime ranges of 6 h were determined based on the season-diurnal cycle in the three-dimensional winds and were used to sort subsets of ozone data for trend analysis. Significant increasing trends in surface ozone were detected for both daytime (1.5–2.7 ppbv 10 a−1) and nighttime (1.3–2.9 ppbv 10 a−1). Autumn and spring revealed the largest increase rates, while summer and winter showed relatively weaker increases. The HHT spectral analysis confirmed the increasing trends in surface ozone concentration and could further identify four different stages with different increasing rates, with the largest increase occurring around May 2000 and October 2010. A 2–4, 7 and 11 year periodicity was found in the surface ozone concentration. The results are highly valuable for related climate and environment change assessments of western China and surrounding areas, and for the validation of chemical-climate models.

Observational studies on the variations in surface ozone concentration at Anantapur in southern India

2010 ◽  
Vol 98 (1) ◽  
pp. 125-139 ◽  
Author(s):  
B. Suresh Kumar Reddy ◽  
K. Raghavendra Kumar ◽  
G. Balakrishnaiah ◽  
K. Rama Gopal ◽  
R.R. Reddy ◽  
...  
Keyword(s):  
Ozone Concentration ◽  
Observational Studies ◽  
Surface Ozone ◽  
Southern India ◽  
Surface Ozone Concentration

scholarly journals TOAST 1.0: Tropospheric Ozone Attribution of Sources with Tagging for CESM 1.2.2

2018 ◽  
Vol 11 (7) ◽  
pp. 2825-2840 ◽  
Author(s):  
Tim Butler ◽  
Aurelia Lupascu ◽  
Jane Coates ◽  
Shuai Zhu
Keyword(s):  
Tropospheric Ozone ◽  
Surface Ozone ◽  
Chemical Mechanism ◽  
System Model ◽  
Ozone Production ◽  
Anthropogenic Emissions ◽  
Source Attribution ◽  
Volatile Organic ◽  
Community Earth System Model ◽  
Northern Hemispheric

Abstract. A system for source attribution of tropospheric ozone produced from both NOx and volatile organic compound (VOC) precursors is described, along with its implementation in the Community Earth System Model (CESM) version 1.2.2 using CAM4. The user can specify an arbitrary number of tag identities for each NOx or VOC species in the model, and the tagging system rewrites the model chemical mechanism and source code to incorporate tagged tracers and reactions representing these tagged species, as well as ozone produced in the stratosphere. If the user supplies emission files for the corresponding tagged tracers, the model will produce tagged ozone tracers which represent the contribution of each of the tag identities to the modelled total tropospheric ozone. Our tagged tracers preserve Ox. The size of the tagged chemical mechanism scales linearly with the number of specified tag identities. Separate simulations are required for NOx and VOC tagging, which avoids the sharing of tag identities between NOx and VOC species. Results are presented and evaluated for both NOx and VOC source attribution. We show that northern hemispheric surface ozone is dominated year-round by anthropogenic emissions of NOx, but that the mix of corresponding VOC precursors changes over the course of the year; anthropogenic VOC emissions contribute significantly to surface ozone in winter–spring, while biogenic VOCs are more important in summer. The system described here can provide important diagnostic information about modelled ozone production, and could be used to construct source–receptor relationships for tropospheric ozone.

scholarly journals Response of surface ozone concentration to emission reduction and meteorology during the COVID-19 lockdown

2021 ◽  
Author(s):  
Adrien Deroubaix ◽  
Benjamin Gaubert ◽  
Idir Bouarar ◽  
Thierno Doumbia ◽  
Yiming Liu ◽  
...  
Keyword(s):  
Ozone Concentration ◽  
Rural Areas ◽  
Surface Ozone ◽  
The United States ◽  
Pollutant Emissions ◽  
Atmospheric Composition ◽  
Northern Europe ◽  
Relative Reduction ◽  
Ozone Concentrations ◽  
Monitoring Stations

<p>During the COVID-19 pandemic, the first lockdown period (March-May 2020) has led to an unprecedented reduction in pollutant emissions. For 3⁄4 of the more than 1,100 available monitoring stations in Europe, the average NO2 concentrations decreased by at least 25% (2.7 μg.m-3) compared to the average concentrations recorded during the same period of the previous seven years. The relative reduction was of similar magnitude in both urban and rural areas.</p><p>We further investigate the spatial distribution of the O3 change. Relative to the seven years average, positive anomalies were observed in northern Europe and negative anomalies in southwestern Europe. However, the level of total oxidant (Ox = O3 + NO2) remained unchanged except in southwestern Europe where it decreased.</p><p>At the global scale, the ozone concentration increased only in a few NOx-saturated regions. After presenting data from monitoring stations in Europe, we analyze the drivers of the change in surface ozone concentrations using the global Community Earth System Model. We contrast global simulations of the atmospheric composition with and without lockdown adjusted anthropogenic emissions for the COVID-19 period.</p><p>By comparing the situation in Europe with that of the United States and China, we show that the reduced cloudiness in northern Europe played a significant role by shifting the photochemical partitioning between NO2 and O3 toward more ozone, while in the North China Plain, enhanced ozone concentrations resulted primarily from reduced emissions of primary pollutants.</p><p>These results illustrate the complexity of the processes affecting ozone in the troposphere and hence the difficulty of implementing efficient regulations targeting air quality impacts.</p>

scholarly journals Late-Spring and Summertime Tropospheric Ozone and NO<sub>2</sub> in Western Siberia and the Russian Arctic: Regional Model Evaluation and Sensitivities

2020 ◽  
Author(s):  
Thomas Thorp ◽  
Stephen R. Arnold ◽  
Richard J. Pope ◽  
Dominic V. Spracklen ◽  
Luke Conibear ◽  
...  
Keyword(s):  
Dry Deposition ◽  
Tropospheric Ozone ◽  
Western Siberia ◽  
Surface Ozone ◽  
Late Spring ◽  
The Arctic ◽  
Transport Sector ◽  
Anthropogenic Emissions ◽  
Negative Bias ◽  
Russian Arctic

Abstract. We use a regional chemistry transport model (WRF-Chem) in conjunction with surface observations of tropospheric ozone and Ozone Monitoring Instrument (OMI) satellite retrievals of tropospheric column NO2 to evaluate processes controlling the regional distribution of tropospheric ozone over Western Siberia for late-spring and summer in 2011. This region hosts a range of anthropogenic and natural ozone precursor sources, and serves as a gateway for near-surface transport of Eurasian pollution to the Arctic. However, there is a severe lack of in-situ observations to constrain tropospheric ozone sources and sinks in the region. We show widespread negative bias in WRF-Chem tropospheric column NO2 when compared to OMI satellite observations from May – August, which is reduced when using ECLIPSE v5a emissions (FMB= -0.82 to -0.73) compared with the EDGAR-HTAP-2 emissions data (FMB= -0.80 to -0.70). Despite the large negative bias, the spatial correlations between model and observed NO2 columns suggest that the spatial pattern of NOx sources in the region is well represented. Based on ECLIPSE v5a emissions, we assess the influence of the two dominant anthropogenic emission sectors (transport and energy) and vegetation fires on surface NOx and ozone over Siberia and the Russian Arctic. Our results suggest regional ozone is more sensitive to anthropogenic emissions, particularly from the transport sector, and the contribution from fire emissions maximises in June and is largely confined to latitudes south of 60° N. Large contributions to surface ozone from energy emissions are simulated in April north of 60° N, due to emissions associated with oil and gas extraction. Ozone dry deposition fluxes from the model simulations show that the dominant ozone dry deposition sink in the region is to forest, averaging 6.0 Tg of ozone per month, peaking at 9.1 Tg of ozone deposition during June. The impact of fires on ozone dry deposition within the domain is small compared to anthropogenic emissions, and is negligible north of 60° N. Overall, our results suggest that surface ozone in the region is controlled by an interplay between seasonality in atmospheric transport patterns, vegetation dry deposition, and a dominance of transport and energy sector emissions.

scholarly journals Modeling the Surface Ozone Concentration in Campo Grande (MS)—Brazil Using Neural Networks

2015 ◽  
Vol 07 (04) ◽  
pp. 171-178 ◽  
Author(s):  
Amaury de Souza ◽  
Flavio Aristone ◽  
Ismail Sabbah
Keyword(s):  
Neural Networks ◽  
Ozone Concentration ◽  
Surface Ozone ◽  
Surface Ozone Concentration
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