Abstract/Summary

Air pollution has become an increasingly pressing issue over the past decades. Studies have now estimated that over 91% of death using data from the Global Burden of Diseases, Injuries, and Risk Factors Study in 2019. In this regard, the impact of air pollution on human health, particularly in developing countries, is of primary concern. Despite the serious air pollution in Lagos, Nigeria, public perception of air pollution and real-time air quality measurement remain largely unexplored. In this study, air pollution and air quality in Mushin, Oshodi, Ikeja and Agege metropolis of Lagos were assessed. Lagos had been experiencing such air pollution problems in all its severity over the past decades. Most of the identified air pollution in Lagos is associated with high density of industries and transport networks. Key contributors include vehicular and industrial emissions, poor waste management practices like open burning, and industrial activities. This pollution is linked to approximately 11,200 premature deaths annually from ambient PM2.5, with children under five being particularly vulnerable, and also results in significant economic costs to the state. The impacts of air pollution include loss of life, chronic respiratory illness, cardiovascular defects and carcinogen. Other consequences of air pollution include corrosion to various materials which causes damage to cultural resources, acid rain, damage of crops and vegetation. In this research, an anonymous questionnaire survey was conducted online, along with face-to-face respondents, using a structured questionnaire. Focus groups interviews were conducted with records, which was transcribed to text. The interviews were conducted with designated participants from the study areas. Air pollutants assessment was conducted, which utilised the use of Airly low-cost sensors to measure air pollutants, including particulate matter (PM1), particulate matter (PM25), particulate matter (PM10), nitrogen dioxide (NO2), and ozone (O3), temperature, wind speed, pressure and humidity. Both the questionnaire (involving a total of 3,766 respondents) and the interviews (comprising 4 focus groups and 37 individual interviews) indicated that vehicle traffic, open burning emissions, industrial activities, and exhaust fumes from electric generators were the most common sources of air pollution in Lagos State. This study investigates air pollution dynamics, health risks, and public awareness in Lagos, Nigeria, using low-cost Airly sensors, surveys, and focus group discussions. Air quality monitoring revealed persistent exceedances of World Health Organization (WHO) guidelines, with PM₂.₅ (64 µg/m³ dry; 52 µg/m³ wet) and PM₁₀ (75 µg/m³ dry; 59 µg/m³ wet) far above annual thresholds, O₃ (85 µg/m³ dry) approaching the 8-hour limit, and NO₂ (42 µg/m³ wet; 39 µg/m³ dry) nearing guideline levels. Seasonal analysis showed dry-season peaks for PM and O₃ (p < 0.001) and higher wet-season NO₂ (p = 0.016), while diurnal variations revealed rush-hour NO₂ and PM spikes, and midday O₃ surges. A strong negative correlation between NO₂ and O₃ (r = –0.65) confirmed photochemical processes typical of tropical megacities, contrasting with traffic-dominated cycles in European cities. Spatial mapping identified Oshodi as a hotspot for NO₂ and PM, and Ikeja for O₃, reflecting traffic, industrial activity, and meteorological influences. These findings underline Lagos’s increasing public health and ecological risks, driven by traffic, industry, and seasonal weather patterns. This study demonstrates the usefulness of low-cost sensors in capturing spatial and temporal pollution trends and stresses urgent policy actions: expanding monitoring networks, engaging the public through trusted channels, implementing stricter emission control measures, and conducting seasonal interventions aimed at dry-season particulate matter and wet-season NO₂. Survey and focus group findings highlighted limited awareness: 56.3% of respondents were unaware of air quality regulations, 87.9% expressed dissatisfaction with government action, and reliance on social media (28.9%) exceeded official channels (5.5%). Health risks were recognised anecdotally, such as asthma and lung inflammation, but broader impacts, including cardiovascular disease, were poorly understood. Chi-square analyses established strong associations between kerosene and gas use and reported health issues (p = 0.000), while environmental concerns included acid rain (43.5%), vegetation damage (19.4%), and climate change (16.7% Monitoring air pollution levels through community-based participation helped to better understand the exposure levels to air pollutants. This is a novel form of 'citizen science' in cities of developing countries. Apparently, respondents do not view air quality control and its management through effective governance as adequate. To obtain useful information about air quality, it is indispensable to measure air pollution levels using low-cost sensors. The results of this study suggest that community-based initiatives in Lagos must be enhanced to lower pollution levels, including education on the harmful effects of poor air quality.