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Investigating the spatial distribution of land surface temperature as related to air pollution level in Tehran metropolis
2023
Nasehi, Saeedeh | Yavari, Ahmadreza | Salehi, Esmael
Urban Heat Island (UHI) is a common urban problem associated with a wide variety of factors, including air pollution. This study investigated the relationship between Land Surface Temperature (LST) and air pollution as two spatial phenomena affecting urban areas. LST was estimated from OLI sensor images taken on 01/07/2020 using the single-channel algorithm. Air pollution was assumed to be indicated by the concentrations of NOX, NO2, NO, PM2.5 and SO2, which were obtained by Inverse Distance Weighting (IDW) interpolation from the data recorded on the same date as satellite images. Correlations were measured in terms of R and R2 and errors were estimated in terms of RMSE, MAE and MBE. The highest R and R2 were obtained for SO2 (20.89 and 45.99, respectively). The results showed that despite the high correlation between SO2 and LST, PM2.5 has a much better error distribution. Therefore, further research should be conducted on the relationship between these indices.
Show more [+] Less [-]A Regression-Based Analysis to Assess the Impact of Fluoride Reach River Water on the Groundwater Aquifer Adjacent to the River: A Case Study in Bharalu River Basin of Guwahati, India
2020
Das, M. | Bhattacharjya, R. K.
Fluoride is one of the parameters which is non-degradable and naturally occurring inorganic anion found in many natural streams, lakes, and groundwater. Serious problems are faced in several parts of India due to the high consumption of fluoride through drinking water. These may cause dental and skeletal fluorosis to humans. This study aims to examine the level of fluoride in both Bharalu river water and groundwater within Guwahati city, Assam, India, and also to analyze the impact of fluoride reach river water on the groundwater aquifer adjacent to the river. From the investigation, it has been observed that the concentration of fluoride varies from 0.02 to 3.73 mg/l in river water and 0.04 to 4.7 mg/l in the case of groundwater. The statistical analysis shows that there is a strong correlation between the fluoride concentration of river water and groundwater. This indicates that the groundwater might have contaminated by the polluted river water.
Show more [+] Less [-]Daytime Ozone Variation in Surface Air in a Subtropical Mangrove Estuary at Manakudy, South India
2018
Krishna Sharma, R. | Chithambarathau, T | Elampari, K. | Nagaveena, S.
Surface ozone (SOZ) can be very harmful if it exceeds the threshold limit. It can accumulate over sea and can return back to the land along with the breeze. Rural and vegetation rich areas often record elevated levels of surface ozone because of the variations in Volatile Organic Compound (VOC) levels, wind velocity and direction. Similarly methane is also an important greenhouse gas and plays a vital role in the atmospheric budget. In this work, ozone and methane levels measured during daytime in a mangrove estuary near Manakudy(8.0911 N, 77.477 E),kanyakumari, South India for a period of ten months from March 2014 to December 2014 are analyzed.SOZ showed an imprecise diurnal pattern with an early morning peak whereas methane recorded an apparent diurnality. The maximum value of SOZ was around 50 ppb. Summer months recorded high levels of SOZ followed by Southwest monsoon (SWM) and Northeast monsoon (NEM).High levels of methane were found in SWM followed by NEM and low concentration during summer. The correlation between SOZ and methane was found as r = -0.257, p
Show more [+] Less [-]Summer time variation and unexpected nocturnal peak in precursors related Surface ozone concentration in air over a tropical coastal regionof Southern Tamil Nadu, India
2016
Krishna Sharma, R | Nagaveena, S
Surface ozone (Surface O3)is a secondary pollutant and there are only limited studies on ozone in South India. Studies have revealed a strong correlation between higher ozone levels and warmer days. Surface O3 along with its precursors like NO2, CO and CH4 are being measured at Kanyakumari (8.0780° N, 77.5410° E), TamilNadu, India and in this paper we present the summer time variation of ozone from 2010to 2014 . Surface O3 showed a clear diurnal variation, but an irregularity was observed during the night time for all the measuring days of Summer 2014.There was a formation of a well pronounced secondary peak in Surface O3 during 0230 hrs accompanied by relatively strong wind patterns. Since the normal diurnal variation cannot explain this phenomenon,this uncertain behavior is probably attributed tolow NOX titrations and the downward mixing of ozone in the ground layer.The daily mean of Surface O3showed an increasing trend in the study area during the summer monthsand a negative correlation was observed with its precursors. The correlation of Surface O3 with temperature and wind speed for the entire summer season was found as r= +0.68, p= 4.314E-05 and r= +0.63, p
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