جستجوی مقالات مرتبط با کلیدواژه "ازون" در نشریات گروه "جغرافیا"

The release of isoprene from plants is the largest known source of non-methane volatile organic compounds in the world, indicating a direct transfer of carbon and a reaction of plants to the atmosphere. It is estimated that more than 90% of isoprene emissions from plants occur during peak hours of photosynthesis (11 to 20). Given that isoprene is an ozone precursor and its direct effect on ozone release is further determined in the biosphere; the main purpose of this study is to identify the generating areas of this pre-pollutant in vegetated areas by monitoring tropospheric ozone data. Ozone data were prepared from air pollution measuring stations and monitoring stations of the Environment Organization from 2002 to 2018, and after producing the NDVI map of Tehran, an analysis based on the correlation method between variables was performed. The results showed that from 11 to 20 o'clock in areas where the vegetation index is higher within a radius of one kilometer of each station, the amount of emitted ozone is higher and there is a significant relationship between the two, indicating the production of isoprene by the dominant tree and shrub species. در is in such areas. Isoprene is mainly produced from fast-growing trees such as spruce, willow, eucalyptus, acacia, sycamore, etc., which can increase ozone pollution in the earth's surface; Therefore, before developing a new green space, the municipalities of different areas of Tehran metropolis are recommended to accurately identify the species suitable for the urban environment and the effect of their pollution in a completely scientific manner and, if necessary, plant such trees in some areas. Assume that they are not exposed to isoprene production catalyst conditions.

Ozone is a very small part of earth atmosphere, but its presence is nevertheless vital to human well-being. Most ozone resides in the upper part of the atmosphere. This region called the stratosphere is more than 10 kilometers above earth's surface. About 90 percent atmospheric ozone is contained in the ozone layer or ozonosphere which shields every living thing from ultraviolet light from the sun. Total ozone is all the ozone in the atmosphere. Total ozone values often report in Dobson units. Typical values vary between 200 to 500 Dobson over the globe. Total ozone varies strongly with spatial (latitude) and temporal over the planet. This paper with using different statistical as regression analysis, variance analysis and Student- Newman-Keuls (SNK) methods tried to discover the relationship between total ozone and time variation in monthly, seasonal and annual time scale in Isfahan ozone metric station. Analysis of variance shows significant different between time series means p<0.01. The best series agreement with the among of ozone is seasonal series so that average of among of ozone shows a significant in each season with S.N.K test but monthly and yearly mean of ozone dont show significant difference in all of months and years. Spring has the maximum of seasonal mean of ozone and fall has the minimum of it. Results of study on trend indicate a no significant trend in the annual mean in the time series.

In this paper, the concept of Thermal Island has been discussed in general. First of all, the definition of the city’s thermal island and its history have been presented using illustrations and diagrams. Next, the climate variables affecting thermal islands have been considered. The purpose of the research is to introduce the city’s thermal island or the point of maximum of heat in the city, which mostly includes the city center. The term “thermal island” refers to the fact that city is warmer than its suburbs and surrounding area, which in some cases can show in a difference in temperature of 5-8 ° C. The research method in the paper is documentary, secondary and with the help of utilization of electronic sources and various websites. In addition, the hypothetical factors that create the cap layer covering the city’s thermal island are mentioned, and the radiation level in the urban area, its comparison with the suburbs and the effects it has on human health and the environment have been studied. Finally, strategies for dealing with Thermal Island through improving public behavior in relation to protecting the environment, developing green space, etc. have been examined and proposed.