Project – Household Generator Emissions, Ventilation Practices and Respiratory Symptoms: An Environmental Health Assessment of Selected Residential Communities in Lagos State.

CHAPTER ONE

INTRODUCTION

Topic: Household Generator Emissions, Ventilation Practices and Respiratory Symptoms: An Environmental Health Assessment of Selected Residential Communities in Lagos State

1.1 Background to the Study

The quality of the environment in which people live has significant implications for their health and general wellbeing. One of the major environmental health concerns in residential communities is exposure to air pollutants generated from domestic energy sources, particularly petrol- and diesel-powered electricity generators. Household generators have become common in many developing countries where electricity supply is unreliable, making alternative sources of power necessary for domestic activities. Although generators provide electricity for lighting, refrigeration, entertainment, water pumping and other household needs, their operation releases harmful substances into the surrounding environment. These emissions may include carbon monoxide (CO), nitrogen oxides (NOx), sulphur dioxide (SO₂), carbon dioxide (CO₂), volatile organic compounds and particulate matter. Prolonged exposure to these pollutants may affect the respiratory system and contribute to other adverse health outcomes. The World Health Organization (WHO, 2025) identifies household air pollution as an important environmental health risk associated with respiratory diseases, cardiovascular conditions and premature mortality. Similarly, Oguntoke and Adeyemi (2017), in their investigation of emissions from fossil-fuel-powered electricity generators in Abeokuta, Nigeria, established that generator emissions contributed to environmental air pollution and were associated with health complaints among exposed residents. These findings demonstrate that household electricity generation, although economically and socially useful, may create environmental health risks when generators are operated without adequate precautions.

Household generator emissions constitute an important source of environmental pollution because the combustion of petrol and diesel releases gases and particles that may contaminate the air within and around residential buildings. The nature and concentration of these emissions depend on several factors, including the type of fuel, generator capacity, engine condition, duration of operation, maintenance practices and distance between the generator and occupied buildings. Carbon monoxide is particularly dangerous because it is a colourless and odourless gas that interferes with the ability of blood to transport oxygen. Exposure to elevated concentrations may result in headaches, dizziness, weakness, confusion, unconsciousness and, in severe cases, death. Other pollutants, such as nitrogen dioxide and fine particulate matter, can irritate the respiratory tract and contribute to breathing difficulties. Oriakpono et al. (2022), in their investigation of pollutants emitted from selected electricity generators used in Nigerian households, identified carbon monoxide, nitrogen oxides, sulphur dioxide and particulate matter among the substances released during generator operation. Similarly, the United States Environmental Protection Agency (EPA, 2024) warns that portable generators produce dangerous carbon monoxide emissions and should never be operated inside homes, garages or other enclosed or partially enclosed spaces. These findings highlight the importance of understanding the composition of household generator emissions and the possible consequences of exposure among residents.

The increasing use of private electricity generators in Nigeria is closely associated with persistent electricity supply challenges and the need for households to maintain regular access to power. Many residential households depend on petrol- and diesel-powered generators to support domestic activities, particularly during prolonged electricity interruptions. While generators provide an alternative source of electricity, their frequent operation may expose household members and neighbouring residents to exhaust emissions. The health implications may be more serious where generators are positioned close to windows, doors, balconies, kitchens or other openings through which exhaust gases can enter living spaces. Oguntoke and Adeyemi (2017) observed that generator sites recorded substantial concentrations of air pollutants and that pollutant levels varied with distance from generator locations. In a Nigerian study, Saka (2021) also examined the environmental effects of fossil-fuel-powered generators and reported health-related complaints, including choking sensations, dizziness and impaired visibility among affected respondents. Furthermore, Azodo et al. (2021), in their investigation of portable gasoline generators and residential indoor air quality in Abeokuta, found that several indoor air quality parameters increased during generator operation compared with measurements taken before operation. These studies indicate that generator use is not merely an energy issue but an environmental health concern that requires attention to generator placement, operating duration and exposure conditions within residential communities.

Ventilation practices are equally important in determining the extent to which generator emissions affect indoor air quality and the health of household occupants. Ventilation refers to the process through which outdoor air enters a building and indoor air is removed or replaced to maintain acceptable indoor environmental conditions. Effective ventilation can help dilute and remove indoor contaminants, while inadequate ventilation may allow pollutants to accumulate within residential spaces. In homes where windows and doors are frequently closed, natural airflow is restricted, particularly when buildings have poor architectural designs or limited ventilation openings. The WHO (2021), in its global air quality guidelines, emphasises the importance of reducing exposure to harmful airborne pollutants because of their adverse effects on human health. Similarly, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE, 2022), through Standard 62.2, provides requirements for ventilation and acceptable indoor air quality in residential buildings. However, ventilation alone cannot make it safe to operate a generator indoors or close to building openings. Akintola (2025), in a Nigerian study examining safe generator locations around residential buildings, demonstrated the importance of considering generator placement and pollutant dispersion when assessing the potential for emissions to enter occupied buildings. Therefore, understanding household ventilation practices alongside generator operating patterns is essential for evaluating residential exposure to generator-related air pollution.

Respiratory symptoms represent some of the most immediate and recognisable health concerns associated with exposure to environmental air pollutants. These symptoms may include persistent coughing, wheezing, chest tightness, nasal irritation, excessive mucus production, shortness of breath and difficulty breathing. Exposure to carbon monoxide, nitrogen dioxide, particulate matter and other combustion-related pollutants may irritate the respiratory tract, worsen existing respiratory conditions and contribute to adverse pulmonary outcomes. The WHO (2021) explains that exposure to air pollution can cause airway inflammation, impair respiratory health and increase the risk of several non-communicable diseases. In addition, Guarnieri and Balmes (2014), in their review of outdoor air pollution and asthma, established that air pollutants can contribute to respiratory inflammation and exacerbate asthma symptoms. In a Nigerian study, Oguntoke and Adeyemi (2017) reported that residents exposed to generator-related emissions experienced health complaints, including nasal congestion and coughing. Similarly, the study by Ugbede et al. (2025) on household generator fumes in Nigerian suburban communities reported associations between high exposure and respiratory complaints such as chronic cough, shortness of breath and wheezing. These findings suggest that respiratory symptoms should be considered important health indicators when investigating the effects of household generator emissions.

The Nigerian residential environment presents particular challenges for controlling exposure to generator emissions because households differ in building design, available space, generator positioning, ventilation facilities and environmental awareness. In densely populated communities, generators may be positioned in corridors, balconies, narrow passages or close to neighbouring residential buildings because of limited outdoor space. Consequently, emissions released by one household may affect individuals living in adjacent buildings, creating an environmental exposure problem that extends beyond the household operating the generator. Abdulazeez et al. (2012), in their investigation of indoor exposure to hazardous air pollutants and volatile organic compounds in low-income houses in Lagos, identified petrol generator use, kerosene cooking and insecticide use as important contributors to indoor air pollution. Their study also reported unhealthy indoor air quality conditions in some of the residential rooms examined. Furthermore, Oguntoke and Adeyemi (2017) demonstrated that generator emissions contributed to environmental degradation and health complaints among residents in an urban Nigerian setting. These findings indicate that household generator emissions should be investigated within the broader context of residential environmental conditions, housing characteristics and household practices, particularly in densely populated urban communities where residents may share similar exposure environments.

Lagos State provides an important setting for investigating household generator emissions, ventilation practices and respiratory symptoms because of its large urban population, residential density, diverse housing conditions and dependence on alternative electricity sources. Residential communities across the state include high-density neighbourhoods, low-income settlements, medium-density residential estates and more developed housing areas, each with different environmental and building characteristics. These differences may influence generator placement, duration of operation, airflow within homes and the level of exposure experienced by residents. In their study of residential and transportation-sector air pollution in Lagos Mainland, the researchers identified household generator use and domestic activities as important sources of air pollution in residential areas (Air Pollution Monitoring Around Residential and Transportation Sector Locations in Lagos Mainland, 2018). Abdulazeez et al. (2012) also documented indoor exposure to hazardous air pollutants in residential communities in Shomolu, Mafoluku and Mushin, Lagos State. More recently, the WHO (2025) emphasised the importance of reducing household air pollution through improved energy technologies and exposure-reduction measures. Against this background, the present study seeks to assess household generator emissions, ventilation practices and respiratory symptoms among residents of selected residential communities in Lagos State. It will investigate household generator-use patterns, residents’ ventilation practices, reported respiratory symptoms and the relationship between generator-related exposure and respiratory health, with the aim of generating evidence that can support environmental health interventions and safer residential energy practices.

1.2 Statement of the Problem

The increasing dependence on petrol- and diesel-powered household generators has created an important environmental health concern in Nigerian residential communities. Although these generators provide electricity for domestic activities, their combustion processes release potentially harmful gases and particulate matter into the surrounding environment. Residents may be exposed to these pollutants when generators are operated close to residential buildings, windows, doors and other openings through which exhaust emissions can enter indoor spaces. Such exposure may result in respiratory irritation, headaches, dizziness and other adverse health effects, particularly when generators operate for prolonged periods or are poorly maintained. Oguntoke and Adeyemi (2017) established that fossil-fuel-powered generators contributed to air pollution and reported health complaints among exposed residents in Abeokuta. Similarly, Oriakpono et al. (2022) identified several potentially harmful pollutants in the exhaust emissions of generators commonly used in Nigerian households. Despite the widespread use of generators, many residential households may continue to operate them without sufficient consideration of the environmental and health risks associated with their emissions. This raises concerns about the extent to which residents of selected Lagos communities are exposed to generator-related air pollutants.

Another major problem concerns the positioning and operation of household generators in relation to residential buildings. In many urban communities, limited residential space, building arrangements and inadequate awareness of generator safety may encourage households to position generators close to balconies, windows, corridors and other building openings. When exhaust emissions are released near these openings, pollutants may enter indoor environments and expose household occupants. The situation may become more complicated where buildings have inadequate ventilation or where windows and doors remain closed for extended periods. Akintola (2025) highlighted the importance of safe generator positioning in Nigerian residential environments, while Azodo et al. (2021) demonstrated that indoor air quality parameters could increase during the operation of portable gasoline generators positioned around residential buildings. These findings suggest that generator placement and operating practices are important factors in determining residents’ exposure. However, the extent to which households in selected Lagos residential communities observe appropriate generator positioning and operating practices remains an important environmental health question.

Furthermore, inadequate ventilation practices may increase the accumulation of pollutants within residential buildings and potentially worsen residents’ exposure to generator emissions. Ventilation is essential for maintaining indoor air quality because it facilitates the movement and replacement of indoor air. However, some residential buildings may have limited ventilation openings, poor building orientation, restricted airflow or household practices that reduce natural air circulation. Where generator emissions enter such buildings, inadequate ventilation may contribute to prolonged exposure to harmful pollutants. Abdulazeez et al. (2012) identified unhealthy indoor air quality conditions in some low-income residential houses in Lagos and reported generator use among the contributors to indoor pollution. The WHO (2021) also emphasised that exposure to air pollutants can adversely affect respiratory health and that reducing exposure is essential for disease prevention. The problem, therefore, is that the combined influence of generator-use patterns and household ventilation practices may expose residents to avoidable environmental health risks, yet the extent of these practices and their relationship with respiratory symptoms in selected Lagos communities require further investigation.

The central problem addressed by this study is the limited community-specific understanding of the relationship between household generator emissions, ventilation practices and respiratory symptoms among residents of selected residential communities in Lagos State. Although previous Nigerian studies have investigated generator emissions, indoor air pollution and associated health complaints, there remains a need to examine these factors together within specific residential environments in Lagos. For example, Abdulazeez et al. (2012) examined indoor exposure to hazardous pollutants in selected Lagos neighbourhoods, while Oguntoke and Adeyemi (2017) investigated generator emissions and health complaints in Abeokuta. However, these studies do not fully establish how household generator-use characteristics and ventilation practices interact in relation to residents’ self-reported respiratory symptoms across the selected communities proposed for this study. This creates a need for an environmental health assessment that examines generator-use patterns, ventilation conditions and respiratory symptoms together. Addressing this problem will provide evidence that may assist environmental health authorities, community leaders, household occupants and policymakers in developing practical measures to reduce exposure to generator emissions and improve residential environmental health.

1.3 Objectives of the Study

The main objective of this study is to assess household generator emissions, ventilation practices and respiratory symptoms among residents of selected residential communities in Lagos State.

The specific objectives are to:

1. Assess the patterns of household generator use and the potential exposure of residents to generator emissions in selected residential communities in Lagos State.

2. Examine ventilation practices and their adequacy in reducing residents’ exposure to household generator emissions.

3. Identify the common respiratory symptoms experienced by residents in the selected communities in relation to household generator use.

4. Determine the relationship between household generator emissions, ventilation practices and respiratory symptoms among residents of selected residential communities in Lagos State.

1.4 Research Questions

The following research questions will guide the study:

1. What are the patterns of household generator use and the potential exposure of residents to generator emissions in selected residential communities in Lagos State?

2. What ventilation practices are adopted by households, and how adequate are they in reducing exposure to generator emissions?

3. What are the common respiratory symptoms experienced by residents in the selected communities?

4. What is the relationship between household generator emissions, ventilation practices and respiratory symptoms among residents of selected residential communities in Lagos State?

1.5 Research Hypothesis

The following null hypothesis will guide the study:

H₀: There is no statistically significant relationship between household generator emission exposure, ventilation practices and respiratory symptoms among residents of selected residential communities in Lagos State.

1.6 Significance of the Study

The findings of this study will be significant to residents, environmental health officers, public health professionals, government agencies, community leaders, policymakers, researchers and students.

Residents and Household Members: The study will provide information about the potential health consequences of prolonged exposure to household generator emissions. It will increase awareness of the dangers associated with inappropriate generator positioning, prolonged generator operation and inadequate ventilation. The findings may encourage households to adopt safer generator-use practices and improve their understanding of the importance of protecting children, elderly persons and other vulnerable household members from exposure to harmful emissions.

Environmental Health Officers: The study will provide useful information to environmental health officers responsible for monitoring residential environmental conditions and promoting healthy living environments. It may assist them in identifying households with potentially unsafe generator arrangements and inadequate ventilation practices. The findings may also support community inspections, environmental health education and interventions aimed at reducing household air pollution.

Public Health Professionals: The findings will contribute to public health knowledge concerning the relationship between environmental exposure and respiratory health. They may assist public health professionals in designing health education programmes focusing on air pollution prevention, respiratory disease awareness and household environmental safety. The study may also support early identification of individuals experiencing respiratory symptoms associated with environmental exposures.

Government and Regulatory Agencies: The study will provide evidence that may assist relevant government agencies in developing policies and guidelines concerning the safe operation and positioning of household electricity generators. It may encourage stronger environmental monitoring, public awareness campaigns and enforcement of existing environmental protection standards.

Community Leaders and Associations: Community leaders may benefit from the findings when organising environmental health awareness programmes and promoting safer residential practices. The study may encourage communities to develop collective approaches to generator positioning, waste management, environmental cleanliness and the reduction of avoidable air pollution.

Policymakers: The findings may contribute to policy discussions on household energy security, environmental health protection and urban residential planning. The study may also provide evidence supporting the development of cleaner household energy alternatives and improved residential environmental standards.

Researchers and Students: The study will contribute to existing literature on environmental pollution, household energy practices, ventilation and respiratory health. It will provide a reference point for future research in environmental health, public health, environmental science and related disciplines. Other researchers may use the findings to investigate household air pollution in other Nigerian cities and residential communities.

1.7 Scope of the Study

The study will focus on household generator emissions, ventilation practices and respiratory symptoms among residents of selected residential communities in Lagos State, Nigeria.

Content Scope: The study will examine household generator-use patterns, including generator type, fuel type, frequency of operation, duration of use and distance from residential buildings. It will also investigate ventilation practices, including the availability of windows and ventilation openings, airflow, opening and closing patterns and general residential ventilation conditions. Furthermore, it will assess respiratory symptoms such as coughing, wheezing, chest tightness, nasal irritation and shortness of breath.

Geographical Scope: The study will be conducted in selected residential communities within Lagos State. The selected communities will provide the geographical setting for examining household generator use, ventilation practices and residents’ respiratory health experiences.

Population Scope: The study population will comprise adult residents of selected households within the chosen communities. Particular attention will be given to individuals who have regular exposure to household or neighbouring generators.

Variable Scope: Household generator emission exposure will constitute the principal independent variable, ventilation practices will serve as an additional explanatory or modifying variable, while respiratory symptoms will constitute the dependent variable.

1.8 Operational Definition of Terms

Household Generator: This refers to a petrol- or diesel-powered electricity-generating machine used by households to provide electricity for domestic activities.

Generator Emissions: These refer to gases and particulate substances released into the environment during the combustion of petrol or diesel in electricity generators.

Household Air Pollution: This refers to the contamination of indoor residential air by harmful gases, particles and other pollutants originating from household activities and energy sources.

Ventilation Practices: These refer to the methods and arrangements adopted by households to facilitate the movement and replacement of indoor air through windows, doors, vents and other openings.

Respiratory Symptoms: These refer to physical complaints affecting the respiratory system, including coughing, wheezing, chest tightness, nasal irritation, phlegm production and shortness of breath.

Carbon Monoxide: This is a colourless and odourless poisonous gas produced by incomplete combustion of carbon-containing fuels, including petrol and diesel.

Particulate Matter: This refers to tiny solid particles or liquid droplets suspended in the air that may enter the respiratory system when inhaled.

Indoor Air Quality: This refers to the condition and cleanliness of air within residential buildings in relation to the presence and concentration of pollutants.

Generator Exposure: This refers to the extent to which household occupants come into contact with pollutants released during generator operation, taking into consideration proximity, frequency and duration of exposure.

Residential Communities: These refer to geographical areas comprising households and residential buildings where people live and undertake their daily domestic activities.

Environmental Health Assessment: This refers to the systematic examination of environmental conditions and their potential implications for human health.

Project – Household Generator Emissions, Ventilation Practices and Respiratory Symptoms: An Environmental Health Assessment of Selected Residential Communities in Lagos State.