Environment and Ecology Research 9(4): 173-185, 2021 http://www.hrpub.org DOI: 10.13189/eer.2021.090405 Regional Trend in Ambient Air Quality Footprints in Calabar Urban, Nigeria Josiah Nwabueze Obiefuna 1,* , Gertrude Nnanjar Njar 2 , Francis Ebuta Bisong 1 1 Department of Geography and Environmental Science, Faculty of Environmental Sciences, University of Calabar, P.M.B. 1115, Calabar, Nigeria 2 Department of Surveying & Geoinformatics, Faculty of Environmental Sciences, University of Calabar, P.M.B. 1115, Calabar, Nigeria Received June 7, 2021; Revised July 13, 2021; Accepted August 22, 2021 Cite This Paper in the following Citation Styles (a): [1] Josiah Nwabueze Obiefuna, Gertrude Nnanjar Njar, Francis Ebuta Bisong , "Regional Trend in Ambient Air Quality Footprints in Calabar Urban, Nigeria," Environment and Ecology Research, Vol. 9, No. 4, pp. 173 - 185, 2021. DOI: 10.13189/eer.2021.090405. (b): Josiah Nwabueze Obiefuna, Gertrude Nnanjar Njar, Francis Ebuta Bisong (2021). Regional Trend in Ambient Air Quality Footprints in Calabar Urban, Nigeria. Environment and Ecology Research, 9(4), 173 - 185. DOI: 10.13189/eer.2021.090405. Copyright©2021 by authors, all rights reserved. Authors agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License Abstract Poor air quality is widely considered as one of the major environmental hazards confronting several urban centres worldwide. This study examined regional trend in ambient air quality footprints in Calabar Metropolis. Data on emission level of CO, NO 2 , SO 2 , H 2 S, and SPM 2.5 were collected using Crowcon Gasman, while point coordinates were collected using Garmin GPSMap 60CSx device. Interpolation algorithm in Geographic Information Systems infrastructure was used to generate the regional trend maps for the metropolis. Parametric analytical techniques such as Analysis of Variance (ANOVA) were employed to test the hypotheses, while descriptive statistics including tables, maps and standard deviation were also used to present the data based on the objectives of the study. The results of the trend surface analysis for the five (5) measured parameters show that CO and SPM 2.5 were not significant at P˃0.05 with F-ratio of 0.99 and 2.45 respectively. Thus, the null hypothesis which states that there is no significant change in the regional trend in air quality across Calabar Metropolis was therefore accepted. Analysis for NO 2 , SO 2 and H 2 S, were significant at P < 0.05 with F-ratio of 3.47, 3.35 and 7.79 respectively, causing the null hypothesis to be rejected. It was therefore recommended that mitigatory measures should be employed for the purpose of ensuring a sustainable, clean and green urban environment. Keywords Regional Trend, Environmental Hazards, Disasters, Air Quality, Pollution 1. Introduction Air quality is the condition of air that defines its content level of one or more pollutants such as carbon dioxide (CO 2 ), nitrogen dioxide (NO 2 ), sulphur dioxide (SO 2 ), hydrogen sulphide (H 2 S) and suspended particulate matter of 2.5mm or higher in diameter, etc. The term ‘air quality footprints’ as used in this research denotes measurement, mathematical and graphical expression or depiction in area or land use based units, a set of green house gasses, pollutants or emissions accumulated within the life cycle of dominant economic activities across various land uses. However, when land uses are not properly planned and adhered to, air quality would be affected. This condition would arise when large and numerous sources of emission such as industrial, commercial and transportation are located in close proximity to the residential areas or other air pollution-sensitive facilities such as schools. As a result of this, persons, communities and businesses affected would ultimately suffer negatively either in the form of higher costs of public health, higher mortality rate or higher pollution control cost. The determination of air quality is often achieved by examining air pollutants emitted from anthropogenic activities as well as from nature. In order to improve air