The objective of the study is to develop low-cost IoT based sensor to monitor real-time greenhouse gases (GHG) emissions data from selected industry locations (city blocks) in a top-down approach. Three (3) industry locations were selected within the Suame Industrial complex (the largest single cluster of artisanal engineering and light manufacturing in Sub Saharan Africa and even Africa) which has no reported GHG emissions data. A GHG monitor was developed using Atmega328 microcontroller and a sim800I GSM module was used to collect a 24-hour real-time minute-by-minute emissions data from the selected industry locations. A MQ-4 (methane/natural gas sensor), MQ-135 (Nitrous Oxide sensors) and DHT22 (temperature and humidity sensor) were used in the GHG monitor design. The GHG of concern were carbon dioxide, methane and nitrous oxide. A total of 3627 emissions data were collected and analyzed from the three (3) industry locations. Location 3 had the highest average carbon dioxide emissions of 508.11 ppm, followed by location 2 with 477.31 ppm with the least emissions in location 1 with 472.51 ppm which are above the global carbon dioxide average of 414.7 ppm. The average methane emission was highest in location 1 with 0.1599 ppm (1599 ppb), followed by location 3 with 0.1366 ppm (1366 ppb) with the least average methane emission of 0.1358 ppm (1358 ppb) in location 2 which are slightly below the global methane average of 1895.7 ppb. The MQ-135 nitrous oxide sensor reported zero emissions data throughout the deployment at the various industry locations which indicated the nitrous oxides emission in the selected sample site is negligible or below the detectable range of the sensor.