The Relationship between Vehicular Maintenance and Exhaust Gas Emissions: A Comprehensive Multi-Parametric Empirical Study in Municipal Area in Calabar, Nigeria

Abstract

Vehicle emissions are a major contributor to the deterioration of urban air quality, tropospheric pollution, and localized climate change in developing cities. This detailed study investigates the complex relationship between vehicle maintenance schedules, age, total mileage, and tailpipe emissions specifically carbon dioxide (CO2), carbon monoxide (CO), unburned hydrocarbons (UHC), and sulfur dioxide (SO2) in the rapidly growing urban area of Calabar, Nigeria. Data was collected from a carefully selected sample of 164 operational vehicles, including commercial heavy-duty transport, mass transit buses, light utility vans, and private cars. Advanced laboratory methods, including titration and spectrophotometry, were employed at the University of Calabar to measure carbon and sulfur emissions, while operational surveys gathered information on maintenance frequency, oil change intervals, and engine overhauls. Statistical regression analysis revealed a strong positive correlation (r = 0.84, p < 0.01) between longer service intervals and increased emissions of harmful pollutants. Vehicles that exceeded the recommended maintenance schedules showed up to a 240% increase in carbon and sulfur emissions compared to those that were regularly serviced. Additionally, an analysis of fuel efficiency revealed an average decrease of 18.5% in fuel volume due to delayed maintenance. These results indicate that neglecting vehicle maintenance significantly worsens urban air pollution and economic inefficiency, underscoring the urgent need for policies mandating emission testing, stricter fuel quality regulations, and specialized training programs for mechanics in developing urban areas.