Investigating the Spatio-Temporal Correlation between Atmospheric Heat Island and Pollution Island in the Lower Rio Grande Valley.

Urban Heat Island (UHI) effect occurs when the natural land cover is replaced with high dense concentrations of buildings and built-up area. This leads to an increase in temperatures in the urban areas than the surrounding countryside or suburbs. This effect not only adds to the energy consumption in the affected areas, but also impacts water quality, air quality, and therefore public health in a negative scale. While the atmospheric UHI (AUHI) is calculated using the air temperature observed by site monitoring, the surface UHI (SUHI) is calculated using the temperature data observed by satellites. Similar to UHI, urban pollution island is the region in the urban atmosphere the consists of more pollution particles than the surrounded areas. With gaseous pollutants like ozone warming the climate, and components of PM either having warming or cooling effects on the climate, it is very important to study the relationship between urban heat islands and urban pollution islands.

The Lower RGV includes Hidalgo, Cameron, Willacy, and Starr counties, and is home to 1,399,446 people. _­­­­­ There has been an increase of 13.2% in the population when compared to 2010 and it is accompanied with high economic activities and high environmental exposures due to traffic emissions, agricultural and trash burning, and high diesel emissions near the international ports of entries. With a rapid urbanization taking place in the region, it is very important to study the effects of it on environment. Especially, with the region being a majority-minority community consisting of limited resources, it is highly essential to study the relationship between air pollution and heat island to estimate its effect on public health. The Texas Commission on Environmental Quality (TCEQ) which is the environmental agency for the state operates five Central Ambient Monitoring Site (CAMS), one each in Brownsville, Edinburg, Harlingen, Mission, and Port Isabel. While all of them measure meteorological parameters, only two of them measure ozone and four of them measure PM_2.5. This research aims to integrate the ground-based monitoring data from TCEQ CAMS and satellite data from Moderate Resolution Imaging Spectroradiometer (MODIS), and Sentinel-5 Precursor Tropospheric Monitoring Instrument (TROPOMI) to study the relationship between pollution island and heat island for the Lower Rio Grande Valley. The seasonal variations of urban heat islands will be addressed in the study. While the air pollution data of aerosol optical depth (AOD) will be collected from MODIS, nitrogen dioxide (NO₂), Sulphur dioxide (SO₂), and carbon monoxide (CO) will be extracted from TROPOMI data. Spatial and temporal variations of various air pollutants and the temperature will be presented in the study.