Understanding perceptions, behaviours, and population exposure risks to air pollution in a high-activity urban corridor in Nigeria

Air pollution health impacts remain a critical concern in cities worldwide, yet limited evidence exists on how informal commercial hubs, such as markets and transport corridors where large populations converge, shape exposure risks in African cities. This study examined how socio-demographics, visitation, and perceptions intersect with residential and on-site air quality to assess risks in Watt Market, Calabar, Nigeria. Data were collected through online and in-person surveys on demographics, visitation, perceptions, and behaviours, supplemented by Air Quality Index (AQI) data from a previous study. Daily market flows were estimated by combining standardised visitation frequencies and respondent counts across residential groupings, while Population Index values were derived from published thresholds and scaled to daily activity levels. AQI and Population Index data were combined using the Population Exposure Risk Index (PERI) metric developed in this study to classify exposure risk at residential and market levels. Results show Watt Market as a convergence hub, with estimated daily visitation of 14 to 400 individuals per group, all classified within Population Index 1 (low population densities). Residential AQI values ranged from ‘Good’ to ‘Marginally Polluted,’ and PERI results classified all assessed residential groups within the Very Low exposure risk category under the adopted threshold framework. Nonetheless, awareness of interventions was extremely limited (98% unaware), and behavioural adaptation was rare (12.5%). Vulnerability was concentrated among older adults (55+), 41% of whom reported underlying health conditions despite residing mainly in low-AQI zones. These findings suggest that Watt Market currently appears to be associated with relatively low cumulative exposure risk under observed conditions and within the adopted screening framework. Nonetheless, the presence of vulnerable groups and limited awareness highlights the need for continued monitoring and targeted education or interventions. Future studies using larger datasets and dynamic monitoring are also needed to track market-related exposures and strengthen evidence for air quality management in Nigeria.