Background: Indoor air pollution resulting from household cooking fuels remains a major environmental health concern, particularly in low- and middle-income countries where biomass fuels are widely used.
Aim: This study assessed the chemical characteristics of indoor air pollutants and evaluated the associated respiratory health risks among households using different cooking fuels in Rivers State, Nigeria.
Materials and Methods: A comparative cross-sectional study involving 120 households was conducted across selected communities in Rivers State. Indoor concentrations of PM₂.₅, PM₁₀, carbon monoxide, nitrogen dioxide, sulphur dioxide, total volatile organic compounds, formaldehyde and benzene were measured using calibrated real-time air quality monitors and portable gas analysers. Exposure concentration, estimated daily inhalation dose, chronic daily intake, hazard quotient, hazard index and incremental lifetime cancer risk were calculated using standard United States Environmental Protection Agency health risk assessment models. Data were analysed using descriptive and inferential statistics at p < 0.05.
Results: Mean PM₂.₅ concentrations ranged from 29.8 ± 7.4 µg/m³ among LPG users to 192.6 ± 44.8 µg/m³ among firewood users, while PM₁₀ concentrations ranged from 56.4 ± 12.6 to 326.4 ± 68.5 µg/m³. Firewood users recorded the highest concentrations of carbon monoxide (19.4 ± 4.8 mg/m³), nitrogen dioxide (98.6 ± 20.4 µg/m³), sulphur dioxide (44.8 ± 10.6 µg/m³), total volatile organic compounds (584.6 ± 118.2 µg/m³), formaldehyde (82.4 ± 18.7 µg/m³) and benzene (13.4 ± 3.2 µg/m³). Hazard Index values ranged from 0.62 ± 0.14 among LPG users to 4.26 ± 0.62 among children exposed to firewood smoke. Incremental lifetime cancer risk ranged from 4.26 × 10⁻⁷ to 4.18 × 10⁻⁵. Chronic cough (63.3%), eye irritation (73.3%) and wheezing (53.3%) were most prevalent among firewood users. Cooking fuel type, cooking duration and ventilation significantly predicted indoor pollutant concentrations (Adjusted R² = 0.748; p < 0.001).
Conclusion: Biomass fuels generated substantially higher indoor pollutant concentrations and respiratory health risks than cleaner fuels. Promoting cleaner household energy sources and improving kitchen ventilation could significantly reduce indoor air pollution and associated respiratory health effects.
