Indoor/Outdoor Concentration of Pollutants Around Major Roundabouts in Ilorin Metropolis, Nigeria

The Met One Aerocet 531s apparatus assessed indoor and outdoor particulate matter concentrations. Additionally, the Crowcon Gas Pro, a versatile multi-gas measurement equipment, facilitated the quantification of gaseous pollutants, including Oxygen, Carbon monoxide, Carbon dioxide, Hydrogen sulfide, and Methane. The assessment of other gaseous pollutants, such as NO, NO2, and NH3, was conducted using the ToxiRAE II apparatus, which offers diverse measurement capabilities. The Kestrel weather tracker contributed to the study by furnishing microclimatic parameters. All measurement instruments were strategically positioned at approximately 1.5 meters above ground level.

Vehicular density variation emerged as a pivotal criterion in the evaluation process. Findings revealed elevated outdoor PM10 concentrations during rush hours at the roundabouts, indicating heightened pollutant emissions during peak traffic times. Conversely, intriguingly elevated indoor PM10 concentrations were observed within specific indoor environments during non-rush hour periods. This phenomenon potentially results from the interplay of meteorological fluctuations and indoor activities, underscoring the complexity of pollutant dispersion dynamics.

Indoor-to-outdoor concentration ratios emerged as a significant metric, consistently exceeding unity across diverse sites. This observation substantiates the presence of indoor-based pollutant sources, necessitating vigilant monitoring and effective mitigation strategies to mitigate potential health risks for indoor occupants.

This research contributes vital insights into the intricate domain of air quality assessment, offering nuanced perspectives on pollutant distribution dynamics, indoor exposure scenarios, and ensuing health implications. By addressing the complex nexus between outdoor and indoor environments, this study emphasizes the imperative of adopting comprehensive strategies to curtail pollutant emissions at their source, foster sustainable urban planning, and enhance the quality of indoor environments. The outcomes resonate with broader endeavours to address the far-reaching consequences of air pollution on both ecological equilibrium and human well-being.