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Bangladesh is among the countries with the highest concentrations of particulate matter and other air pollutants, according to the World Health Organization. The Department of Environment of Bangladesh has installed air monitoring systems in Dhaka, Chattogram, Khulna, Rajshahi, Barishal, Gazipur, and Narayanganj to observe daily gaseous pollutants and particulate matter (PM) concentrations in those cities. This study analyzed the concentration of gaseous and particulate pollutants from 2018 to 2023 in these urban areas of Bangladesh. Ambient air concentrations of PM2.5, PM10, carbon monoxide (CO), oxides of nitrogen (NOx) and ozone (O3) were monitored in the dry and wet seasons for these cities. Temporal variability including hourly, day of the week, monthly, and seasonal variations of particulate matter and gaseous pollutants (except seasonal variation) were assessed. Both PM2.5 and PM10 exceeded the Bangladesh National Ambient Air Quality Standard (BNAAQS) and the World Health Organization (WHO) air quality guidelines during the observed period for all the observed regions. PM2.5 mean concentration was maximum in Narayanganj i.e., 109.7 µg/m3 (313% of the limit of the air quality standard), and PM10 mean concentration was maximum in Narayanganj i.e., 203.3 µg/m3 (407%). Among the observed cities, Khulna had the better air quality although it was not satisfactory at all. However, the gaseous pollutants were within permissible limits. The temporal patterns suggested that vehicles, brick kilns, and industries were responsible for the poor air quality in Bangladesh. The air quality during the period in which COVID-19 was most prevalent (2020–2021) was compared to the two years prior and post to that interval. In general, air quality improved during the COVID period, but in the post-COVID period, they returned to concentrations similar to the pre-COVID period. After identifying possible pollutant sources, these results will assist decision-makers in taking action and implementing policies to control air pollution in cities.

All over the world, unplanned land conversion, especially in urban areas, has become a burning issue, resulting in an increase in surface temperature. The Rajshahi district of Bangladesh is not an exception, where greenery and water bodies are decreasing because of massive infrastructural development. Thus, the study aims to highlight the relationship between land surface temperature and land cover by using GIS and remote sensing approaches. The results of the study reveal that the land surface temperature ranges from 26.18°C to 38.91°C and the temperature difference between urban and rural areas is 1–2°C. However, there is no comfort zone (temperature between 16°C and 25°C) in the year of 2019. More than 81% of the land had a temperature between 26°C and 32°C and about 18% has been delineated as a very hot zone (more than 32°C), within which 50% of the land is in the Rajshahi City Corporation (RCC). Also, a linear regression analysis was conducted to know how temperature is related to different indices where land surface temperature (LST) was negatively correlated with normalized difference vegetation index (NDVI) and normalized difference water index (NDWI), while an affirmative relationship was found between LST and normalized difference built-up index (NDBI). Thus, the study helps to impede the rising temperature not only for the study area but also for other cities by providing an indicator to the concerned development authorities.

Artificial lighting is essential for supporting human activities during nighttime. Excessive artificial light causes pollution. This type of pollution impairs our ability to see the night sky clearly and results in the wasteful consumption of excessive energy. This research investigates the extent and impact of light pollution in the rapidly urbanizing cities of Rajshahi and Dhaka, employing Geographic Information Systems (GIS) and remote sensing techniques. The primary objectives of this thesis are to assess the extent and intensity of light pollution in the study areas. The authors utilized multi-temporal DMSP/OLS nighttime light satellite imagery spanning the period from 1992 to 2013. Additionally, VIIRS Day/Night Band (DNB) images from 2013 to 2022, accessed through Google Earth Engine, were employed to provide more recent data for analysis. These datasets were processed and analyzed within a GIS framework to delineate the extent of light pollution and its temporal evolution, allowing for the identification of hotspots and trends over the years. The findings of this study reveal the profound impact of urbanization on light pollution, with notable differences between the two cities. Despite the geographically smaller size of the Dhaka district than the Rajshahi district, the total amount of nighttime light is substantially larger in Dhaka. Light pollution, which differs in terms of spatial position, contributes to Dhaka City's rapid urbanization, which includes industrial and commercial activity and is located in the middle of Bangladesh. On the other side, Rajshahi, which is located in northern Bangladesh, has less light pollution than Dhaka because of its relative lack of industrial and commercial activity.

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