Tropospheric ozone concentration over Pakistan

2022 ◽  
pp. 349-365
Author(s):  
Ramsha Munir ◽  
Umer Khayyam
2011 ◽  
Vol 17 (4) ◽  
pp. 403-413 ◽  
Author(s):  
C. Okan Sakar ◽  
Goksel Demir ◽  
Olcay Kursun ◽  
Huseyin Ozdemir ◽  
Gokmen Altay ◽  
...  

2021 ◽  
Author(s):  
Inês Vieira ◽  
Hans Verbeeck ◽  
Félicien Meunier ◽  
Marc Peaucelle ◽  
Lodewijk Lefevre ◽  
...  

<p>Tropospheric ozone is a greenhouse gas, and high tropospheric ozone levels can directly impact plant growth and human health. In the Congo basin, simulations predict high ozone concentrations, induced by high ozone precursor (VOC and NOx) concentrations and high solar irradiation, which trigger the chemical reactions that form ozone. Additionally, biomass burning activities are widespread on the African continent, playing a crucial role in ozone precursor production. How these potentially high ozone levels impact tropical forest primary productivity remains poorly understood, and field-based ozone monitoring is completely lacking from the Congo basin. This study intends to show preliminary results from the first full year of in situ measurements of ozone concentration in the Congo Basin (i.e., Yangambi, Democratic Republic of the Congo). We show the relationships between meteorological variables (temperature, precipitation, radiation, wind direction and speed), fire occurrence (derived from remote sensing products) and ozone concentrations at a new continuous monitoring station in the heart of the Congo Basin. First results show higher daily mean ozone levels (e.g. 43 ppb registered in January 2020) during dry season months (December-February). We identify a strong diurnal cycle, where minimum values of ozone (almost near zero) are registered during night hours, and maximum values (near 100 ppb) are registered during the daytime. We also verify that around 2.5% of the ozone measurements exceeds a toxicity level (potential for ozone to damage vegetation) of 40 ppb. In the longer term, these measurements should improve the accuracy of future model simulations in the Congo Basin and will be used to assess the impact of ozone on the tropical forest’s primary productivity.</p>


Author(s):  
Juan Gómez-Sanchis ◽  
Emilio Soria-Olivas ◽  
Marcelino Martinez-Sober ◽  
Jose Blasco ◽  
Juan Guerrero ◽  
...  

This work presents a new approach for one of the main problems in the analysis of atmospheric phenomena, the prediction of atmospheric concentrations of different elements. The proposed methodology is more efficient than other classical approaches and is used in this work to predict tropospheric ozone concentration. The relevance of this problem stems from the fact that excessive ozone concentrations may cause several problems related to public health. Previous research by the authors of this work has shown that the classical approach to this problem (linear models) does not achieve satisfactory results in tropospheric ozone concentration prediction. The authors’ approach is based on Machine Learning (ML) techniques, which include algorithms related to neural networks, fuzzy systems and advanced statistical techniques for data processing. In this work, the authors focus on one of the main ML techniques, namely, neural networks. These models demonstrate their suitability for this problem both in terms of prediction accuracy and information extraction.


Author(s):  
Nguyen Thi Thu Phuong ◽  
Mac Duy Hung ◽  
Duong Thanh Nam ◽  
Nghiem Trung Dung

Support vector machine (SVM) and multilayer perceptron (MLP) were used to forecast hourly tropospheric ozone concentration at three locations of Quang Ninh, namely Cao Xanh, Uong Bi and Phuong Nam. Data used to train the models are the hourly concentrations of gaseous pollutants (O3, NO, NO2, CO) and meteorological parameters including wind direction, wind speed, temperature, atmospheric pressure, relative humidity measured in the 2016. Both models accurately forecast tropospheric ozone levels compared to the observation data. The correlation coefficients (r) of the models applied for the three locations range from 0.85 to 0.91. In addition, SVM exhibits a more accurate prediction than MLP, especially for those with large variations, i.e. high standard deviations.


2005 ◽  
Vol 39 (34) ◽  
pp. 6352-6361 ◽  
Author(s):  
Edmilson Dias de Freitas ◽  
Leila Droprinchinski Martins ◽  
Pedro Leite da Silva Dias ◽  
Maria de Fátima Andrade

2020 ◽  
Author(s):  
Igor V. Ptashnik ◽  
Boris D. Belan ◽  
Denis E. Savkin ◽  
Gennadii N. Tolmachev ◽  
Tatayana K. Sklyadneva ◽  
...  

<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>


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