Concentration of noxious gases inside and outside residential apartments across different settlements in Port Harcourt metropolis, Nigeria

Abstract

The proliferation of harmful gases is a major global problem caused by anthropogenic activities. This study hypothesized that the emission of noxious gases varies seasonally in indoor and outdoor environments. Air samples were collected from 40 georeferenced residential areas (N = 40) in Port Harcourt using Aeroqual 500 monitor to measure six gases: CH4, CO, NH4, NO2, O3, and SO2. Samples were collected at different times, locations, and seasons. The analysis of variance (ANOVA) indicates a significant difference in concentration between gases, times, and locations at p < 0.001. But the interaction effect shows that times and seasons significantly affect noxious gas concentration compared to location. In general, the concentration of CO was the highest, while that of O3 was the lowest. The order of concentration is CO > SO2 > NO2 > CH4 > NH4 > O3. The concentrations of NO2 and SO2 were higher than the WHO limit, while CO, CH4, NH, and O3 were below the WHO limit. Furthermore, CO concentration was highest in the morning, while NO2 and SO2 concentrations were highest in the evening. For seasons, the CH4, NH4, NO2, and SO2 were higher during the dry season, while CO concentration was higher during the wet season. Pollutant levels should be regularly monitored to help provide exposure advisory to city dwellers on the impact of atmospheric pollution on their health.