Spatio-Temporal Modeling of Ozone Distribution in Tehran, Iran Based on Neural Network and Geographical Information System

Background: Air pollution is one of the most important causes of respiratory diseases that people face in big cities today. Suspended particulates, carbon monoxide, sulfur dioxide, ozone, and nitrogen dioxide are the five major pollutants of air that pose many problems to human health. We aimed to provide an approach for modeling and analyzing the spatiotemporal model of ozone distribution based on Geographical Information System (GIS). Methods: In the first step, by considering the accuracy of different interpolation methods, the Inverse distance weighted (IDW) method was selected as the best interpolation method for mapping the concentration of ozone in Tehran, Iran. In the next step, according to the daily data of Ozone pollutants, the daily, monthly, and annual mean concentrations maps were prepared for the years 2015, 2016, and 2017. Results: Spatial and temporal analysis of the distribution of ozone pollutants in Tehran was performed. The highest concentrations of O3 are found in the southwest and parts of the central part of the city. Finally, a neural network was developed to predict the amount of ozone pollutants according to meteorological parameters. Conclusion: The results show that meteorological parameters such as temperature, velocity and direction of the wind, and precipitation are influential on O3 concentration.

Simulation of the Multi-Timescale Stratospheric Intrusion Processes in a Typical Cut-Off Low over Northeast Asia

This study used the FLEXPART-WRF trajectory model to perform forward and backward simulations of a cut-off low (COL) event over northeast Asia. The analysis reveals the detailed trajectories and sources of air masses within the COL. Their trajectories illustrate the multi-timescale deep intrusion processes in the upper troposphere and lower stratosphere (UTLS) caused by the COL. The processes of air intrusion from the lower stratosphere to the middle troposphere can be divided into three stages: a slow descent stage, a rapid intrusion stage and a relatively slow intrusion stage. A source analysis of targeted air masses at 300 hPa and 500 hPa shows that the ozone-rich air in the COL primarily originated from an extratropical cyclone over central Siberia and from the extratropical jet stream. The sources of air masses in different parts of the COL show some differences. These results can help explain the ozone distribution characteristics in the main body of a COL at 300 hPa and at 500 hPa that were revealed in a previous study.

Ozone variation over tropics: Trends revealed from Dobson measurement over Indian stations

. Variations in ozone amounts have been studied using data obtained with Dobson spectrophotometers during 1966-1988 at Srinagar, New Delhi, Pune and Kodaikanal. Yearly average values of total ozone , and its vertical distribution by the Umkehr method in layers 1 to 9 have been computed. Departures from compo- site avarage value for the period (1966-1988) have been computed for both total ozone and its vertical distribution. The variation over New Delhi and Pune have been compared with those at Arosa reported by Dutsch {1989). The observed variations in the ozone distribution at New Delhi and Pune can be explained, as being within normal interannual changes. Tropospheric ozone in layer lover New Delhi shows some effects of an anthropogenic nature, on the other hand Pune does not exhibit in any influence of pollutants in any layer, either in the troposphere or stratosphert.

Solar activity influence on the ozone vertical distribution from SBUV data

<p>Ozone content in the terrestrial atmosphere is dependent on chemical and dynamical factors including catalytic destruction under the influence of chlorine and bromine, Brewer–Dobson circulation, and large-scale atmospheric waves. The appearance of ozone molecules in the stratosphere is caused by solar ultraviolet radiation as well. Therefore solar activity variations can influence ozone content. The 11-year solar cycle had been earlier identified in the upper stratosphere. Satellite ozone observations were begun from the 1970s are almost continuous from 1979 including the vertical ozone distribution, in particular with the use of Solar Backscattered UltraViolet (SBUV) instruments. These data cover the troposphere and stratosphere layers, from the surface to near 50 km. Vertical ozone distribution over the Ukrainian Antarctic station Akademik Vernadsky (65.25°S, 64.27°W) and in the corresponding latitudinal range 60–65°S is studied in this work with the following analysis of possible solar activity display in other latitudinal belts. Sunspot numbers have been considered as the simplest characteristics of solar activity. We have considered SBUV yearly data paying main attention to the time range from 1979 when the measurements are most reliable. Periodicity in the series of ozone layer content has been studied with use of wavelet transform. Processing of the SBUV data over Vernadsky has shown a dominating period near 10–11 years at the heights 18–31 km. In the troposphere and lower stratosphere, this period is unclear. A similar situation is observed above 31 km indicating the upper altitudinal threshold in the presence of the 10–11-year periodicity in the ozone data. The solar cycle influence on the ozone vertical distribution in the Antarctic region has been studied. From our analysis, the solar cycle plays an important role in the decadal variability of the mid-stratospheric ozone over Vernadsky Station with decrease of the effect both in the troposphere – lower stratosphere and in the upper stratosphere. A similar analysis is also realized for zonal mean ozone at the 60–65°S latitudes belt and for the region of zonal ozone maximum (Casey), where the solar cycle was indicated at the heights 31–37 km. Thus, zonal asymmetry in the heights of the maximum solar cycle effect in the Antarctic ozone exists. Periods close to 11 years are observed in the lower stratosphere of equatorial latitudes exhibiting seasonal dependency. At altitudes, 25–30 km, the southern stratosphere has more evident signs of solar cycle periods than the northern one. The summer upper stratosphere with a high flux of direct solar radiation is also a region with prominent quasi-11 year periods. In sum, three main regions with solar activity influence (tropical lower stratosphere, west Antarctic middle stratosphere, and east Antarctic upper stratosphere) are identified. The asymmetry between solar cycle influence (i) in the northern and southern hemisphere mid-stratosphere and (ii) zonal ozone maximum and minimum over Antarctica is denoted for the first time.</p><p>This work was partly supported by the project 19BF051-08 Taras Shevchenko National University of Kyiv and by the International Center of Future Science, Jilin University.</p>

ELECTROZONING AIR AT THE ENTERPRISES OF AGROINDUSTRIAL COMPLEX

The article provides an analysis of the process of electric ozonation of air in the production facilities of agricultural enterprises. The work evaluated the performance of various ozonizers and their control schemes, found that the most effective is the introduction of an ozonizer installation in a ventilation and air conditioning system or its own system, an algorithm for controlling the uniformity of ozone distribution and a functional diagram is presented, and the chemical composition of the air environment is compared to and after the process of electrozoning of air.

Ozone chemistry on tidally locked M dwarf planets

ABSTRACT We use the Met Office Unified Model to explore the potential of a tidally locked M dwarf planet, nominally Proxima Centauri b irradiated by a quiescent version of its host star, to sustain an atmospheric ozone layer. We assume a slab ocean surface layer, and an Earth-like atmosphere of nitrogen and oxygen with trace amounts of ozone and water vapour. We describe ozone chemistry using the Chapman mechanism and the hydrogen oxide (HOx, describing the sum of OH and HO2) catalytic cycle. We find that Proxima Centauri radiates with sufficient UV energy to initialize the Chapman mechanism. The result is a thin but stable ozone layer that peaks at 0.75 parts per million at 25 km. The quasi-stationary distribution of atmospheric ozone is determined by photolysis driven by incoming stellar radiation and by atmospheric transport. Ozone mole fractions are smallest in the lowest 15 km of the atmosphere at the substellar point and largest in the nightside gyres. Above 15 km the ozone distribution is dominated by an equatorial jet stream that circumnavigates the planet. The nightside ozone distribution is dominated by two cyclonic Rossby gyres that result in localized ozone hotspots. On the dayside the atmospheric lifetime is determined by the HOx catalytic cycle and deposition to the surface, with nightside lifetimes due to chemistry much longer than time-scales associated with atmospheric transport. Surface UV values peak at the substellar point with values of 0.01 W m−2, shielded by the overlying atmospheric ozone layer but more importantly by water vapour clouds.