Introduction
Air pollution remains the most significant environmental risk factor for human health globally (1). Over half of the world’s population resides in cities due to rapid population transition and urbanisation, and by 2050, the number is expected to rise to 68% (2). Although one of the most important principles of preserving health and well-being is maintaining clean air, this principle is often overlooked (3, 4). Air pollution levels have increased in major urban centres primarily due to factors such as high vehicular emissions, industrial activities and burning of fossil fuels, especially in developing countries. According to a report by the World Health Organization (WHO), 90% of the global population resides in regions where pollutants exceed air quality guidelines needed to protect health (5). Around 78% of carbon emissions and significant airborne pollutants are produced in urban cities and negatively impact more than 50% of the world’s population (6). In addition, WHO in 2019 estimated that ambient (outdoor) air pollution was responsible for 4.2 million premature deaths globally, and nearly 90% of these deaths occurred in low- and middle-income countries (LMICs), such as Nigeria (5, 7).
Indoor burning of solid fuels is the dominant source of household air pollution (HAP), especially in developing countries (8). When burnt, solid fuels produce several pollutants, including particulate matter and gases of sulfur, nitrogen and carbon that affect human health and cause several health burdens, including cardiovascular diseases (CVDs) (9). In developing countries such as Nigeria, women disproportionately suffer from the impact of this burning, given that they are constantly responsible for cooking, accounting for 5% of all female deaths (10). This confines women to a particularly higher risk owing to the prolonged duration of time spent in the kitchen compared to men (11). On the other hand, ambient air pollution significantly impacts individuals who spend most of their time outdoors (12), including the commercial motor drivers of buses, cars and motorcycles. These occupations are mainly held by men, representing an important part of the labour force, especially in LMICs (13). The vehicles they drive are both sources of air pollution for the drivers and others who work in the outdoor environment. Considering the level of exposure of these vulnerable populations of women and men, their knowledge, attitude and preventive behaviour (KAB) towards air pollution reduction have not been extensively explored, especially in developing countries.
The significant health effects of exposure to air pollution are now well established, with a growing recognition that air pollution has major adverse effects on all organs of the human body (14). Long-term or short-term exposure to air pollutants increases the risk of several health conditions, including cancer (15, 16), respiratory (17, 18) and cardiovascular (19, 20) diseases, leading to elevated morbidity and mortality. In 2016, WHO reported that almost 58% of ambient air pollution-related premature deaths were due to ischaemic heart disease (IHD) and stroke, while 18% of deaths were due to chronic obstructive pulmonary disease (COPD) and acute lower respiratory, and 6% of deaths were due to lung cancer (21). Chronic exposure to air pollution has been linked to a 5–10% increased risk of myocardial infarction, stroke, heart failure and sudden death onset (22). The risk increases by 1–2% for every 10 µg/m3 increase in particulate matter size 2.5 microns (PM2.5) concentrations (23).
In Nigeria, unregulated emissions from power plants, malfunctioning transportation systems and the increased rate of industrial and construction activities have contributed immensely to the increasing levels of air pollution. The uncontrolled emissions from gas flaring and other petroleum refining activities are also major causes of air pollution concerns in the country (24, 25). In 2015, over 51% of the total gases produced in Nigeria were reported flared, accounting for between 10,500 and 5,100,00 tons of pollutants emitted, including PM (26). According to a report by the Nigeria Bureau Statistics, the total number of registered cars on Nigerian roads increased to about 11.8 million in the year 2018, with almost 630,868 additional driver’s licenses issued that same year (27). These vehicles run on fossil fuels, which account for over 90% of the total consumption of petroleum products in Nigeria (28). Government-level solutions to reduce the level of exposure to air pollution depend on industrial transformation and require a cumulative effort before the desired resultant effect can be observed. These solutions include enforcing regular servicing of commercial motor vehicles, reducing the use of unclean fuel and achieving emission-reduction targets which could all yield long-term benefits. In addition, designing interventions targeted at improving knowledge about air pollution might be promising in promoting lifestyle approaches for preventing or reducing air pollution exposure, thereby improving cardiovascular health. However, data on this phenomenon are scarce, especially among vulnerable populations from LMICs.
The KAB framework explains that a person’s knowledge directly influences their attitudes, which in turn, indirectly affects their healthcare-related behaviours and decision-making (29). According to this framework, it can be assumed that individuals’ knowledge about air pollution and CVDs shapes their attitudes towards these issues, and that their attitudes, in turn, influence the actions (behaviours) they take. Given the potential long-term effect of air pollution on quality of life, there is a paucity of data on the knowledge of community members regarding the cardiovascular benefits of reduced exposure to air pollution. This study aims to gather baseline data on the knowledge gap regarding air pollution and cardiovascular health to inform a more extensive intervention study. The CARDINAL study was comprehensively designed to evaluate the impact of a novel AirHealth educational intervention on community members’ KAB towards indoor and outdoor air pollution reduction strategies. Through this survey, we seek to assess pertinent antecedent factors associated with the knowledge, attitude and perception of community members on the cardiovascular benefits of reduced exposure to air pollution, with the ultimate goal of informing strategies and policies to address this critical environmental issue in Nigeria.
Methodology
Study design, population and eligibility
This baseline assessment is part of the Community-Based Cardiovascular Risk Reduction through Novel Air Health Behavioural Change Intervention (CARDINAL) project, which is a pre- and post-interventional community-wide assessment to evaluate the impact of a novel AirHealth intervention. Details on the CARDINAL protocol have been published (30). Briefly, the study was conducted in Ibadan North Local Government Area (LGA) of Ibadan, Oyo State, Nigeria, which is primarily inhabited by Yoruba speakers. The population consists mainly of traders, artisans, civil servants and students. The study included vulnerable populations of men (commercial transport workers) and women (exposed to indoor burning of solid fuel) who were ≥18 years old and had been residing in the selected communities for more than 12 months.
Sample size determination, community entry and sampling strategy
The sample size calculation for the CARDINAL study has been published elsewhere (30). Briefly, assuming an absolute proportional change in a specific KAB component of 0.13 with a standard deviation of 2.5 at 80% power and a drop rate of 10%, a minimum size of 300 participants in each of the vulnerable populations of men and women will be sufficient to observe a difference of approximately 2.1. In addition, details of the CARDINAL community entry through the ward development committee (WDC) have also been previously described (30). A total of five distinguished persons from the different wards in Ibadan North LGA were identified and recruited to form the Community Advisory Network (CAN). In total, 300 commercial transport workers and 300 reproductive-aged women were identified and recruited using a multi-stage sampling technique, as described in the protocol (30). In stage one, a purposive selection of five wards from a total of 12 wards in Ibadan North LGA where the target population of vulnerable men and women resides, was carried out. This was followed by a clustering of communities based on shared characteristics such as the presence of associations of women, caterers, charcoal sellers, firewood sellers and commercial transport (tricycle, motorcycle and bus) drivers/workers. Therefore, two clusters were selected from each ward using simple random sampling with the aid of balloting procedure. Subsequently, site visits were carried out, which allowed us to purposively select one community per cluster, prioritising those with the highest population size and density. In stage three, eligible groups of women, including caterers, charcoal sellers, firewood sellers and men who were commercial transport (tricycle, motorcycle and bus) workers were identified in each selected cluster. After this, a simple random sampling using balloting of women from women’s associations (50% from general women group, 20% from caterers’ association, 20% from charcoal sellers’ group and 10% from firewood sellers’ group) and men from the commercial transport workers’ associations (50% from bus, 30% motorcycle and 20% tricycle drivers) was carried out in stage four until the required sample size was obtained.
Data collection method and tools
The instrument for data collection was a pre-tested semi-structured AirHealth questionnaire, which had a Yoruba language translation to ensure clarity and detailed understanding of the questions. The tool contained inquiries on awareness about air pollution, knowledge of air pollution reduction strategies, knowledge of CVDs and the link with air pollution, attitude towards air pollution reduction and perception relating to air pollution reduction. The questions were developed through a review and adaptation of items from previous studies (31, 32, 33, 34, 35, 36) by a multidisciplinary team of trained experts. The instrument underwent validation by a group of public health experts and was pretested in another community that was not part of the main study before its finalisation. The questionnaire consisted of eight sections. The first section asked about the sociodemographic characteristics of the participant, including age assessed quantitatively, religion categorised as christians, muslims and traditionalists, the highest level of education assessed as ‘no formal education’, ‘primary’, ‘secondary’ and ‘tertiary’, respondents’ income collected in dollars and so on. The second and third sections consisted of a 11-point and 10-point scale on air pollution awareness and knowledge of air pollution reduction strategies. In the fourth section, an 8-point scale was used to assess the knowledge of community members on the link between air pollution and CVDs. The fifth section contained a 16-point Likert scale with five levels on the attitude of participants towards air pollution reduction strategies, ranging from strongly agree to strongly disagree, while the sixth section assessed the behaviour of participants towards air pollution exposure reduction using a 12-point behavioural scale. After validation, the questionnaire was digitalised using the KoBo collect toolbox for easy administration (37). The general meeting periods of the women’s and men’s associations in the selected communities were targeted for data collection by the research assistants (RAs). Data collected were stored in the cloud and later transferred to SPSS for analysis. Data were collected with the help of 12 trained RAs. The RAs were individuals with at least a master’s degree in any science/health discipline, capable of speaking Yoruba and a good understanding of Ibadan North LGA terrain. The RAs were exposed to a 2-day training covering the aims and objectives of the CARDINAL project with specific emphasis on the methodology, the definition of essential variables and the instrument for data collection (AirHealth questionnaire) and ethical issues involved in the study. At the end of every recruitment, the RAs met with the study team weekly for debrief.
The level of knowledge on the link between exposure to air pollution and CVD was assessed using a 10-point knowledge scale. A correct answer for each item was scored ‘1’ and an incorrect answer was scored ‘0’. Using the median knowledge score, ≤6.0 was categorised as poor knowledge, while >7.0 was considered as good knowledge. Attitude towards air pollution reduction strategies was assessed using a 16-point attitude scale. Depending on the direction of the question on the Likert scale, strongly agree was coded ‘5’ while strongly disagree was coded ‘0’. A score above the median attitude score, >10.0, was categorised as a positive attitude, while ≤10.0 was categorised as a negative attitude. Furthermore, preventive behaviour towards air pollution reduction was assessed using an 11-point scale. A correct answer for each item was scored ‘1’ and an incorrect answer was scored ‘0’. Using the median behaviour score, >6.0 was considered as satisfactory behaviour, while ≤6.0 was categorised as unsatisfactory behaviour. In this study, KAB scores were dichotomised in line with several KAB studies (38, 39, 40).
Data processing and analysis
Demographic characteristics of the participants were described using absolute and relative frequencies. Continuous data were presented as median (interquartile range [IQR]), while categorical data were presented as frequencies and proportions. The KAB scores were presented with a box plot due to the lack of compliance with the normality assumption. The bivariate analyses between sociodemographic characteristics and KAB categories were conducted using cross tabulation, whereas the quantitative variables were compared using Mann–Whitney U. Finally, multi-variable regression models were performed to identify sociodemographic and lifestyle factors associated with KAB. All statistical analyses were conducted using SPSS version 27 and R programme version 4.0. Data were analysed at 95% level of significance.
Results
Sociodemographic characteristics of the participants
The study included 602 respondents, with a mean age of 44.1 ± 17.0 years. Respondents <50 years of age constituted 62.1%. Females were slightly more represented, accounting for 54.2% of participants. The dominant religion was Islam (69.0%), followed by Christianity (30.8%). Most (87.6%) of the respondents were from the Yoruba ethnic group. The majority (73.6%) of the respondents were from monogamous families, and almost half (49.6%) had secondary education as their highest level of education (Table 1).
Table 1
Sociodemographic characteristics of the respondents.
| SOCIODEMOGRAPHIC CHARACTERISTICS | FREQUENCY (n = 607) | PERCENTAGE (%) |
|---|---|---|
| Age (years) | ||
| Mean ± SD | 44.08 ± 17.03 | 5.4 |
| <20 | 33 | 32.3 |
| 20–29 | 196 | 0.0 |
| 30–39 | 0 | 20.1 |
| 40–49 | 122 | 19.4 |
| 50–59 | 118 | 12.9 |
| 60–69 | 78 | 6.8 |
| 70–79 | 41 | 3.1 |
| ≥80 | 19 | |
| Age (years) | ||
| <50 | 377 | 62.1 |
| ≥50 | 230 | 37.9 |
| Sex | ||
| Male | 278 | 45.8 |
| Female | 329 | 54.2 |
| Religion | ||
| Christianity | 187 | 30.8 |
| Islam | 419 | 69.0 |
| Traditional | 1 | 0.2 |
| Ethnicity | ||
| Yoruba | 532 | 87.6 |
| Igbo | 15 | 2.5 |
| Hausa | 60 | 9.9 |
| Marital Status | ||
| Single | 116 | 19.1 |
| Married | 420 | 69.2 |
| Separated | 5 | 0.8 |
| Divorced | 8 | 1.3 |
| Widowed | 58 | 9.6 |
| Type of family | ||
| Monogamy | 447 | 73.6 |
| Polygamy | 160 | 26.4 |
| Highest level of education | ||
| No formal education | 86 | 14.2 |
| Primary | 158 | 26.0 |
| Secondary | 301 | 49.6 |
| Tertiary | 62 | 10.2 |
| Household size | ||
| <5 | 271 | 44.7 |
| ≥5 | 336 | 55.4 |
| Respondent’s income | ||
| <$100 | 559 | 92.1 |
| ≥$100 | 48 | 7.9 |
| Spouse’s income | ||
| <$100 | 584 | 96.2 |
| ≥ $100 | 23 | 3.8 |
| Length of stay in years | ||
| <1 | 17 | 2.8 |
| 1–3 | 100 | 16.5 |
| 4–6 | 80 | 13.2 |
| ≥7 | 410 | 67.5 |
Awareness and knowledge of the link between air pollution and CVD
Regarding awareness about air pollution, the majority, 62.3% of respondents, were found to be aware of air pollution (Figure 1). As many as 68.0% identified air pollution as a contributor to stroke, and 65.7% acknowledged its potential to exacerbate chronic heart failure. In addition, 55.7% noted its role in sudden cardiac death, while 51.6% indicated that air pollutants could result in a heart attack (Table 2). In addition, participants demonstrated varied knowledge of air pollution reduction measures. 85.0% reported that biogas usage for cooking could reduce pollution, and 83.4% mentioned the importance of regular motor engine servicing. However, less than half (46.8%) supported public transportation usage as a strategy, and 49.4% suggested using charcoal instead of firewood for cooking. In addition, a little above half (50.7%) of respondents supported biking as a strategy for reducing air pollution (Table 3). The overall median (IQR) knowledge score on the link between air pollution and CVD was 7.0 (IQR: 2.0–10.0), with the majority (66.9%) being classed as having poor knowledge of the link between air pollution and CVD (Figures 2 and 3).
Figure 1
Air pollution awareness.
Table 2
Knowledge of respondents on the link between air pollution and CVD.
| AIR POLLUTION CAN LEAD TO: | FREQUENCY (n = 607) | PERCENTAGE (%) |
|---|---|---|
| Lead to stroke | ||
| No | 194 | 32.0 |
| Yes | 413 | 68.0 |
| Lead to an increase in blood pressure | ||
| No | 267 | 43.9 |
| Yes | 340 | 56.1 |
| Can enter the bloodstream | ||
| No | 338 | 55.7 |
| Yes | 269 | 44.3 |
| Enter lung only without causing CVD | ||
| No | 252 | 41.5 |
| Yes | 355 | 58.5 |
| Result in heart attack | ||
| No | 294 | 48.4 |
| Yes | 313 | 51.6 |
| Exacerbate chronic heart failure | ||
| No | 288 | 44.3 |
| Yes | 399 | 65.7 |
| Lead to sudden cardiac death | ||
| No | 269 | 44.3 |
| Yes | 338 | 55.7 |
| Reduce blood pressure | ||
| No | 267 | 44.0 |
| Yes | 339 | 56.0 |
[i] CVD: cardiovascular disease.
Table 3
Knowledge of respondents on air pollution reduction strategies.
| WHICH OF THE FOLLOWING DO YOU THINK CAN REDUCE AIR POLLUTION | FREQUENCY (n = 607) | PERCENTAGE (%) |
|---|---|---|
| Use of public transportation | ||
| No | 323 | 53.2 |
| Yes | 284 | 46.8 |
| Use of charcoal instead of firewood for cooking | ||
| No | 307 | 50.6 |
| Yes | 300 | 49.4 |
| Tree planting | ||
| No | 276 | 45.5 |
| Yes | 331 | 54.5 |
| Use of air conditioning system at home | ||
| No | 202 | 33.3 |
| Yes | 405 | 66.7 |
| Use of biogas for cooking | ||
| No | 91 | 15.0 |
| Yes | 516 | 85.0 |
| Use of electric stove | ||
| No | 104 | 17.1 |
| Yes | 503 | 82.9 |
| Open burning in the neighbourhood | ||
| No | 218 | 35.9 |
| Yes | 389 | 64.1 |
| Opening of windows while cooking indoors | ||
| No | 125 | 20.6 |
| Yes | 482 | 79.4 |
| Encourage biking | ||
| No | 309 | 50.7 |
| Yes | 299 | 49.3 |
| Regular servicing of motor engines | ||
| No | 101 | 16.6 |
| Yes | 506 | 83.4 |
Figure 2
A box plot representing the median knowledge (A), attitude (B) and behaviour score (C).
Figure 3
Proportion of respondents with poor vs. good knowledge; negative vs. positive attitude; and unsatisfactory vs. satisfactory behaviour.
Attitude towards air pollution reduction strategies
Table 4 presents the issues used in the assessment of the attitude of respondents towards air pollution reduction strategies. Most (84.5%) respondents agreed that community members have a role in reducing air pollution. Strong enforcement of environmental laws was considered as an effective solution by 85.2% of respondents, while 83.9% agreed that banning open burning and dumping could contribute to reducing air pollution. However, 33.4% incorrectly agreed that using firewood for cooking does not impact air pollution. In addition, almost half (49.6%) of the respondents disagreed with cutting down trees as a strategy for reducing air pollution. The attitude ranged from 3.0 to 16.0 with a median score of 10.0. More than half (58.5%) of the respondents had an overall negative attitude towards air pollution reduction strategies.
Table 4
Attitude of respondents towards air pollution reduction strategies.
| FREQUENCY (n = 607) | PERCENTAGE (%) | |
|---|---|---|
| All community members have a role to play in reducing air pollution | ||
| Disagree | 80 | 13.2 |
| Undecided | 14 | 2.3 |
| Agree | 513 | 84.5 |
| Government banning the use of petrol cars can help reduce air pollution | ||
| Disagree | 189 | 31.1 |
| Undecided | 50 | 8.2 |
| Agree | 368 | 60.6 |
| The strong enforcement of environmental protection laws that prohibit air pollution is a good way to start preventing it | ||
| Disagree | 65 | 10.7 |
| Undecided | 25 | 4.1 |
| Agree | 517 | 85.2 |
| Air pollution reduction is strictly Government affair | ||
| Disagree | 404 | 66.6 |
| Undecided | 45 | 7.4 |
| Agree | 158 | 26.0 |
| Open burning and open dumping should be banned to control air pollution | ||
| Disagree | 67 | 11.0 |
| Undecided | 31 | 5.1 |
| Agree | 509 | 83.9 |
| The use of firewood for cooking is an ancient cooking method that doesn’t have anything to do with air pollution | ||
| Disagree | 355 | 33.4 |
| Undecided | 49 | 8.1 |
| Agree | 203 | 33.4 |
| Cutting down trees is a good way to reduce air pollution | ||
| Disagree | 301 | 49.6 |
| Undecided | 63 | 10.4 |
| Agree | 243 | 40.0 |
| Periodic servicing of automobile engine has nothing to do with air pollution reduction | ||
| Disagree | 143 | 73.0 |
| Undecided | 21 | 3.5 |
| Agree | 443 | 23.6 |
Behaviour of respondents towards air pollution reduction
Issues relating to the behaviour of respondents towards air pollution reduction are shown in Table S1. Most (91.2%) of respondents were willing to reduce air pollution exposure to improve their health, and 91.9% indicated readiness to shift from solid fuels to biogas for cooking if available. However, only 22.6% had received advice on air pollution from social or governmental sources, and less than half (43.9%) of the respondents had ever used real-time air quality information to guide their activities (Table 5). The overall median (range) behaviour score was 6.0 (IQR: 1.0–11.0), with majority, 58.6% categorised as having unsatisfactory behaviour.
Table 5
Behaviour of respondents relating to air pollution reduction.
| BEHAVIOUR | FREQUENCY(n = 607) | PERCENTAGE (%) |
|---|---|---|
| Do you know how to perform a seal check on facemask? | ||
| No | 379 | 62.4 |
| Yes | 228 | 37.6 |
| Do you find the use of face mask comfortable during exposure to air pollution? | ||
| No | 158 | 26.0 |
| Yes | 449 | 74.0 |
| Are you ready/willing to substitute biomass fuel (wood, sawdust, kerosene stove) with cleaner fuels such as gas, electric or solar cooker? | ||
| No | 45 | 7.4 |
| Yes | 562 | 92.6 |
| Have you received any form of education on the health risks associated with burning solid fuels for cooking and heating? | ||
| No | 404 | 66.6 |
| Yes | 203 | 33.4 |
| Would you rather consider the use of active transport system such as walking or cycling in a bid to reduce air pollution exposure? | ||
| No | 318 | 52.4 |
| Yes | 289 | 47.6 |
| Can your financial capacity allow you to switch from biomass fuel to cleaner fuels? | ||
| No | 251 | 41.4 |
| Yes | 356 | 58.6 |
| Have you considered the use of real-time information on local air quality from sources such as mobile phone applications, news feeds and websites, to guide route and timing for your movement? | ||
| No | 341 | 56.1 |
| Yes | 266 | 43.9 |
| Have you received any form of advice from your local health care workers on local air quality monitoring so as to minimize exposure? | ||
| No | 387 | 63.8 |
| Yes | 220 | 36.2 |
| Do you have any social group/government source educating you on how to reduce exposure to air pollution in your community? | ||
| No | 470 | 77.4 |
| Yes | 137 | 22.6 |
| Will you be willing to reduce exposure to air pollution to improve your health status? | ||
| No | 54 | 8.9 |
| Yes | 553 | 91.2 |
| If a cleaner stove is made available, will you be willing to shift from solid fuel to biogas for cooking? | ||
| No | 49 | 8.1 |
| Yes | 558 | 91.9 |
Correlation and sociodemographic factors associated with KAB categories
The bivariate analysis revealed that age (p = 0.035), ethnicity (p = 0.013), religion (p = 0.033), education (p = 0.001) and family type (p = 0.01) were influencing factors for knowledge of the link between air pollution and CVD. Attitude towards air pollution reduction strategies was found to be associated with ethnicity (p = 0.021), family type (p = 0.030) and household size (p = 0.035). Factors associated with preventive behaviour towards air pollution reduction include sex (p = 0.001), education (p < 0.001), and awareness about air pollution (p < 0.001) (Table S1). A weak but statistically significant correlation was observed between knowledge and attitude (r = 0.32, p < 0.001), and between knowledge and behaviour (r = 0.13, p = 0.001) (Table S2). In the multivariate regression model, respondents who were aware of air pollution were 18.0% and 56.0% less likely to have poor knowledge (aOR 0.82, 95%CI: 0.57–0.97) and unsatisfactory behaviour (aOR 0.44, 95%CI: 0.31–0.64), respectively, as compared to those who were unaware. Also, males were 42.0% less likely to exhibit unsatisfactory behaviour (aOR 0.58, 95%CI: 0.41–0.83) as compared to females. In addition, monogamy was an independent predictor of poor knowledge (aOR 1.41, 95%CI: 1.03–2.12) and negative attitudes (aOR 1.54, 95%CI: 1.04–2.30) (Table 6 and Figure S1).
Table 6
Adjusted multivariate analysis of sociodemographic factors associated with KAB.
| PREDICTORS | POOR KNOWLEDGE; AOR (95% CI) | NEGATIVE ATTITUDE; AOR (95% CI) | UNSATISFACTORY BEHAVIOUR; AOR (95% CI) |
|---|---|---|---|
| Awareness about air pollution | |||
| No | 1.00 | 1.00 | 1.00 |
| Yes | 0.82 (0.57–0.97) | 0.99 (0.70–1.42) | 0.44 (0.31–0.64) |
| Age (years) | |||
| ≤50 | 1.00 | 1.00 | 1.00 |
| >50 | 0.83 (0.55–1.25) | 0.93 (0.63–1.38) | 0.96 (0.64–1.44) |
| Sex | |||
| Male | 0.94 (0.65–1.36) | 0.75 (0.53–1.06) | 0.58 (0.41–0.83) |
| Female | 1.00 | 1.00 | 1.00 |
| Ethnicity | |||
| Yoruba | 0.17 (0.01–1.33) | 0.10 (0.01–0.75) | 0.91 (0.31–2.71) |
| Hausa | 0.09 (0.01–1.02) | 0.11 (0.01–0.89) | 1.16 (0.35–3.86) |
| Igbo | 1.00 | 1.00 | 1.00 |
| Type of family | |||
| Polygamy | 1.41 (1.03–2.12) | 1.54 (1.04–2.30) | 1.03 (0.68–1.57) |
| Monogamy | 1.00 | 1.00 | 1.00 |
| Highest level of education | |||
| No formal education | 1.00 | 1.00 | 1.00 |
| Primary | 0.74 (0.42–1.30) | 0.62 (0.35–1.10) | 0.76 (0.49–1.19) |
| Secondary | 1.36 (0.77–2.41) | 0.74 (0.42–1.31) | 0.57 (0.32–1.04) |
| Tertiary | 0.67 (0.04–0.92) | 0.99 (0.48–2.15) | 0.42 (0.20–0.89) |
| Household size | |||
| <5 | 1.00 | 1.00 | 1.00 |
| ≥5 | 1.23 (0.85–1.78) | 1.49 (1.05–2.11) | 0.85 (0.60–1.21) |
[i] KAB: knowledge, attitude and behaviour; CI: confidence interval; aOR: adjusted odds ratio.
Discussion
Air pollution remains one of the poorly studied environmental stressors for health in Africa (41). Awareness of the cardiovascular effects of air pollution may be especially poor, despite the increasing scientific evidence showing that air pollution is linked to high levels of cardiovascular morbidity and mortality. To the best of our knowledge, this is the first study in Nigeria to evaluate the KAB of community members regarding the cardiovascular benefits of reduced exposure to air pollution. Identifying the limitations in awareness in this area could help guide the implementation of air quality strategies and improve the effectiveness of interventions addressing environmental health risk factors in African communities.
Our study found an overall poor knowledge of the link between air pollution and CVD among the majority of the community members. A notable contributor was the differences in knowledge among more than half of the participants on the possibility that air pollutants can pass into the bloodstream, to promote oxidative stress, cardiovascular effects and embolism (42). Therefore, improving the knowledge of community members on the cardiovascular impact of exposure to air pollution may be an essential tool for behavioural modification and possible improvement in cardiovascular health. In addition, the poor knowledge of the link between air pollution and CVD was associated with air pollution awareness and the educational status of the respondents. Participants who were aware of air pollution were less likely to have poor knowledge of the link with CVD. Our report resonates with the fact that education is the primary means of acquiring and accumulating knowledge (43). This necessitates the need for awareness creation and improved education on air pollution and underscores the need for targeted educational campaigns to emphasise the cardiovascular risks associated with air pollution. Appreciation of the lifelong burden of CVD due to early and sustained exposure to pollutants (44) may help reinforce awareness building.
Another major finding is the negative attitude towards the air pollution reduction strategy recorded among respondents. Most of the respondents reported that community participation is critical to reducing air pollution, and 85.2% advocated for a strong enforcement of environmental laws. These attitudes resonate with those raised by Ramírez et al. (45), who emphasised the importance of public engagement and policy enforcement in environmental health literacy campaigns. Interestingly, some respondents erroneously believed that using firewood for cooking does not contribute to air pollution. Agbo et al. (46) documented the significant role of biomass combustion in air pollution in the African context. The negative attitude towards air pollution reduction strategies was associated with family type and increased household size. As evident in the current study, individuals belonging to a polygamous family are approximately two times more likely to display a negative attitude towards available air pollution reduction strategies. According to Marín et al. (47), an overpopulated environment, such as a polygamous household, has the potential to trigger negative perceptions and less willingness to act (47), probably due to direct or indirect influence of members of the household. It is important to note that good knowledge can foster a positive attitude (48), although both entities are distinct. For example, a considerable proportion of respondents disagreed that using firewood for cooking does not impact air pollution. This positive attitude might be the result of good knowledge about the contribution of solid fuel use to indoor air pollution. This claim was further supported by the direct positive correlation recorded between knowledge and attitude in the current study. A positive attitude can encourage learning and the application of knowledge, while poor knowledge can lead to a negative reaction (49). A positive behavioural intention was observed among respondents, with almost all respondents willing to reduce air pollution exposure and ready to switch from solid fuels to biogas if available. Marcantonio et al. (50) emphasise the role of access to clean energy sources in fostering environmentally conscious behaviours. However, only 23% had received advice on air pollution from social or governmental sources, suggesting a significant gap in public health communication. The observed economic constraint in terms of respondents’ income could impact individuals’ ability and willingness to change their behaviour (51) towards reducing exposure to air pollution. The likelihood of exposure to HAP has been associated with low household income (52, 53). For example, the inability to afford cleaner fuel could prevent its usage despite the willingness to substitute solid fuel use with cleaner fuel. Therefore, due to the financial limitations experienced by the majority of the population studied, they tend to prioritise immediate needs such as food and shelter over long-term environmental conscious behaviour, leading to less investment in air pollution-reduction strategies. The usage of real-time air quality information by only 44% of respondents highlights the need for increased availability and dissemination of such data, as advocated by Yu et al. (54). Sex disparities were evident, with males more likely to exhibit satisfactory behaviour compared to females, who demonstrated poorer behavioural outcomes. The observed disparity in the sex-specific behaviour could be due to the diverse usage of fuel within and between the populations. This expected diversity in the mode and pattern of fuel usage across different populations is likely to influence their preventive behaviour to make the necessary changes. This aligns with Isezuo et al. (55), who suggest the need for sex-specific interventions to address behavioural gaps. Although weak, the direct correlation between knowledge and attitude supports the theory that informed individuals are more likely to develop favourable attitudes towards pollution reduction (56). However, attitude in the current study did not translate into behavioural modification, probably due to the role of habit and self-control, which are known barriers in the transition of attitude to behaviour (57). Also, the weak relationship between knowledge and behaviour highlights the complexity of translating awareness into action, as previously noted by Kelly and Fussell (58). While awareness is foundational, meaningful behavioural changes require supportive systems, addressing competing motivations and overcoming structural barriers (59), which the African environment has not provided.
Our study found a poor level of knowledge, a negative attitude, and an unsatisfactory behaviour towards air pollution reduction and its link to CVD among a large proportion of vulnerable populations of men and women stratified by occupation as a mode of exposure to air pollution. The results obtained may not reflect the situation among other populations that are less exposed to air pollution. Nevertheless, it is likely that the population studied would be more knowledgeable and exhibit a positive attitude and behaviour towards air pollution than the less exposed (60). Therefore, our study presents a unique opportunity for future longitudinal studies in the general population to develop culturally sensitive interventions to mitigate the cardiovascular health impact of exposure to air pollution.
Strengths and Limitations
This study’s originality and contribution to existing knowledge are major strengths. There is limited research or evidence-based information on community individuals’ KAB towards the cardiovascular benefits of reduced exposure to air pollution in Africa; therefore, this study makes an original contribution to fill this evidence gap in this setting, as well as offering insight into other LMIC settings that may face similar issues. Also, the uniqueness and the sample size of the population studied offer invaluable insights into understanding the complex interplay between environmental awareness and individual actions by identifying the knowledge gap and developing tailored educational interventions. In addition, the AirHealth questionnaire’s extensive validation process, including face validity, content validity, and pilot testing, ensures that the data collected are reliable and valid.
A notable limitation of this study is the occupation-specific grouping that was used in the multi-stage sampling strategy. Although this method is practical, it may introduce selection bias because participants could have similar views or backgrounds, potentially resulting in a non-representative sample. However, efforts were made to mitigate potential bias through further stratification of the population to include a wide range of views and backgrounds. In addition, the absence of qualitative insight in the current study limits the interpretability of the findings, given that attitude and behaviour are mostly socio-culturally influenced. Future mixed-method studies are therefore advocated to provide a comprehensive overview of the cardiovascular benefits of reduced exposure to air pollution. Furthermore, we acknowledged the use of some double-barrelled questions to assess attitude and preventive behaviour, which might impact the specificity of the findings. However, its effect on the validity of the questions and reliability of the findings was mitigated by building the capacity of the RAs and the data team with the knowledge and skills to carefully interpret the questions and findings, in addition to organising a data interpretation meeting with the CARDINAL community advisory network (CAN) and community support groups (CSGs) to allow for data clarity and accuracy.
Conclusion
Community members had poor knowledge, negative attitudes and unsatisfactory behaviour towards the cardiovascular benefits of reduced exposure to air pollution. However, awareness about air pollution was independently associated with good knowledge of the link between air pollution and CVD, while sex disparity was implicated in behaviour towards air pollution reduction. Therefore, strengthening community mobilisation and advocacy may improve their KAB. However, additional studies are warranted to determine the extent to which community engagement can improve KAB. Given the current situation on air pollution and its importance as a major public health concern, studies from Africa are required to identify culturally sensitive strategies to educate the general community to recognise the impact of environmental exposures on health outcomes.
Implications and Recommendations
This study underscores the need for awareness campaigns, policy enforcement and gender-sensitive interventions in improving air pollution-related behaviours in Nigeria and potentially other African communities. Strengthening public health communication, enhancing access to clean energy sources and fostering community engagement will all be vital steps towards reducing air pollution and its associated cardiovascular risks. Our study provides a foundation for a larger upcoming study that will assess the impact of educational intervention. These findings underscore the multifaceted nature of the factors that influence KAB related to air pollution among vulnerable populations of men and women. Understanding these relationships is essential for developing effective targeted interventions and educational strategies to enhance environmental awareness and promote healthier behaviours among vulnerable populations. These insights reinforce the need for policies to support air quality measures, such as subsidising biogas access or integrating air pollution education into primary healthcare.
Additional File
The additional file for this article can be found as follows:
Ethics and Consent
The study was approved by the Oyo State Ministry of Health Ethics Review Committee (Reference number: NHREC/OYOSHRIEC/10/11/22). Support was obtained from community gatekeepers, including Chairs of WDCs and the leadership of commercial transport workers’ associations in the LGA. Written informed consent was obtained by the RA from all participants before the study. Selected participants were asked to keep a copy of the signed informed consent form and another copy documented by the RA who interviewed the participant.
Competing Interests
The authors have no competing interests to declare.
Author Contributions
AGF: Conceptualisation, Investigation, Formal analysis, Funding acquisition, Methodology, Project administration, Writing – original draft, Writing – review & editing. AMA: Investigation, Funding acquisition, Methodology, Project administration, Supervision, Writing – review & editing. TB: Investigation, Visualisation, Writing – review & editing. AOO: Investigation, Visualisation, Writing – review & editing. OM: Investigation, Visualisation, Writing – review & editing. OA: Investigation, Visualisation, Writing – review & editing. SMK: Project administration, Research coordination, Data curation, Writing – review & editing. OPA: Data curation, Formal analysis, Writing – review & editing. MA: Investigation, Writing – review & editing. BEA: Investigation, Writing – review & editing. IMB: Investigation, Writing – review & editing. APO: Visualisation, Writing – review & editing. AO: Investigation, Writing – review & editing. MRM: Writing – review & editing. ACM: Investigation, Writing – review & editing.
Augustine Odili, Amam C. Mbakwem and Abiodun Moshood Adeoye are senior authors.