Globally, air pollution is the leading environmental cause of disease and premature death, and a major contributor to climate change. According to the World Health Organization (WHO), 99% of the world’s population lives in polluted air, and 2.83 million deaths (10.95%) among women and 3.62 million deaths (11.81%) among men have been attributed to air pollution (1). In addition to health concerns, air pollution has economic implications and influences people’s compliance with sustainable development. A 1% increase in air pollution over the preceding three decades has resulted in a 10% increase in healthcare expenses, approximately $8.1 trillion in 2019, and 6.1% of the world’s gross domestic product (GDP) (2).

Although air pollution is a global problem, it is known that 79.3% of deaths attributed to this environmental factor occur in low-and middle-income countries (LMICs) (1), and less than 1% of those cities have air quality that meets WHO standards. The economic burden of air pollution exposure accounts for 9% of GDP in LMICs compared to 2.8% of GDP in high-income countries (HICs), demonstrating the environmental inequalities among people living in and experiencing poverty (3). People experiencing poverty are more likely to live in more polluted environments and to experience declines in economic productivity due to absences from work associated with environmental-related diseases, and in children, up to 43.1% of school absences are due to exposure to PM_2.5 (4).

Reducing air pollution would have a significant impact on the health and well-being of children and adolescents (5–8). It is known that in children under 14 years of age, the primary risk factors associated with mortality are environmental, with air pollution (both outdoor and indoor) and high temperatures being the most significant factors (1). In addition, acute respiratory infections (ARI) are one of the primary causes of death in children; it has been reported that almost 26% of ARI deaths in children aged 5 to 14 are attributable to household air pollution (9).

Among the strategies that could potentially help reduce the adverse effects of air pollution are raising awareness through citizen science projects, adequate risk communication on air quality, and environmental education (10–12). It would have an important impact if environmental agencies formulated citizen science projects to improve and support their existing efforts of outreach and communication (13) and that include perceptions, needs, and values of the target population (14). The U.S. Environmental Protection Agency (EPA) has shown the effectiveness of citizen science projects in properly communicating risk, thereby increasing environmental awareness, and promoting behaviors that reduce exposure to wildfire smoke (12–15).

The relationship between environmental knowledge, pro-environmental attitudes, and practices is complex, and several theories have been proposed to explain the gap between possessing environmental knowledge and exhibiting pro-environmental behavior (16). Some research suggests that educational level could positively influence the level of knowledge about environmental problems and their causes (17, 18) but may not be directly correlated with pro-environmental attitudes (16). It also has been proposed that knowledge influences attitudes and values but does not have a direct impact on pro-environmental practices (16). In addition, being aware of air quality alerts, based on the Air Quality Index (AQI) which contains information about the potential health effects of air pollution, has been linked to changes in practices to reduce exposure in vulnerable individuals with pre-existing diseases (14, 18, 19). The relationship between attitudes and behavior has been more controversial (13); some studies indicate a positive relationship between high pro-environmental attitudes and more ecologically responsible behaviors (20), however, others have shown a non-significant effect (21). Factors contributing to the gap between attitudes and practices include gender, educational level, economic, social, and cultural factors, motivation, attitudes, and values learned within the family, neighborhood, and schools (16, 21, 22).

Given that some aspects of environmental education are taught in elementary and high schools and because a high burden of disease in young people is caused by the environment, it is crucial to understand the knowledge, attitudes, and practices (KAP) that young people have regarding this subject. The majority of KAP studies have been conducted in HICs (18, 23–27), mostly China, the U.S., and a few in low-income countries (LICs) (28, 29) and upper-middle-income countries (21). These studies (23–26, 28, 29) have shown differences in the KAP between countries. The knowledge regarding air composition, causes, and consequences is higher in HICs compared to low-and middle-income countries (LMICs), but the attitudes are different between countries no matter their income. To our knowledge, there are no known studies on KAP about air pollution among high-school students in Latin American or Caribbean countries.

Medellin is the second-largest city in Colombia, with 5% of the country’s population residing there. It is one of the most important centers for industrial, textile, and car development in Latin America (30). During the previous decade, the average yearly levels of PM_2.5 have fluctuated between 20 g/m³ and 33 g/m³ (31), which is four times the WHO-recommended daily values (PM_2.5 annual: 5 g/m³) (32). While national strategies have been implemented to strengthen environmental education in academic institutions through the development and implementation of school environmental projects (PRAE) (33), and local environmental entities have strengthened risk communication (34), it is unknown if these strategies, adopted and implemented by schools, are associated with the increasing KAP levels in children and adolescents in the city. Therefore, we aimed to determine the KAP levels about air pollution among children and adolescents in public and private schools in five municipalities in Colombia, as well as identify factors associated with KAP levels.

There were 1,676 surveys with 15 excluded because of incomplete information. Of the 1,661 students included in the analysis, the median age was 14 years (IQR: 13, 16), with 1% being older than 17 years, 73.3% were between 6^th and 9^th grade, and 53.8% were female. The level of knowledge in the composition of clean air, and on acid rain and the greenhouse effect was higher in private schools than in public schools (p < 0.001) (Table 1).

Three out of five public schools included in the study were classified with the highest importance score (high importance), one was classified as medium, and one was classified as lower, as well as one of the private schools (low importance). None of the three private schools were classified in the high-importance category, as shown in Supplementary Table S3.

To our knowledge, this is the first study in Colombia that evaluates the knowledge, attitudes, and practices of children and adolescents about air pollution and its potential health effects. Overall, the findings of this study showed that 81.1% of participants self-perceived as having low knowledge about air pollution. Other studies have reported a lower percentage of students (65%) who self-rated to have low knowledge about air pollution compared to our study (38).

In our study, children and adolescents had a limited knowledge of the air’s composition, only 31.1% recognized nitrogen as a component of clean air. Our finding is much lower than other studies conducted in Iran (58%), the UK (60%), Australia (53%), and Hong Kong (61%) (23, 28). The fact that many more children and adolescents perceive oxygen as a component of clean, unpolluted air regardless of its concentration, but do not recognize nitrogen as a component, can be attributed to educational approaches. In disciplines such as the sciences, it is possible to understand and verify the active role oxygen plays in a variety of natural ecosystem processes. As a gas that forms the typical mixture of air gases, nitrogen is generally referred to as an air pollutant due to the formation of nitrogen oxides and acids. In terms of ozone and the greenhouse effect, just 34% of participants understood ozone as an air component and 53% associated the greenhouse effect with pollution, compared to 63.7 and 65.3% of Chinese adolescents, respectively (38). These low results could also be explained because some concepts included in the knowledge component in Myers’ questionnaire (24) are related to atmospheric chemistry, which students in lower grades do not have in-depth knowledge of, and because the relationship for some components of the air may be confusing. For example, ozone often causes confusion based on its status as a ground-level pollutant but a protective gas in the stratosphere.

It is essential to address environmental issues in elementary and secondary schools to increase students’ knowledge (11, 17). Our study showed that a third of students had limited knowledge about air pollution and its sources; similar to prior research (24, 39). However, in a Spanish study, 65% of participants were knowledgeable of acid rain, whereas in our study, just 33% knew about it (39). This difference may be explained by the fact that in Europe, particularly in Spain, the problem of air pollution and its effects, specifically acid rain, have been front-page news for more than three decades in newspapers with a wide readership (40), while in our country, disclosure and denunciation of air pollution have just been made in the last decade, focusing especially on particulate matter, which is the pollutant that has increased the most in our region. According to WHO, the annual concentration of PM_2.5 in the last decade for Barcelona, a city similar in urban aspects to Medellín, ranged between12 g/m³ and 18 g/m³, while for the Colombian city, it ranged between 20 g/m³ and 33 g/m³ (41).

In our study, more than 80% of participants associated air pollution as a cause of respiratory diseases, similar to what was found in various research studies (23, 24, 28, 38, 42). This can be explained by the fact that air pollutants are volatile, and as air enters the lungs, it is more easily correlated with pathologies affecting the respiratory tract system. Also, two-thirds of students in our study recognized that air pollution can cause adverse effects in pregnancy, probably due to the strong evidence between air pollution and adverse effects in pregnancy (5, 8, 43, 44), and because children associate polluted air with tobacco, which is strongly linked to adverse effects in pregnancy (45). However, we also acknowledge that children and adolescents may have considered that any outcome was possible, regardless of their actual knowledge about how air pollution is linked to pregnancy outcomes.

We found that students agreed that the strategy of having more education, more duties and taxes, and more legislation to reduce air pollution should be focused on society as a whole, but when measures touch on personal actions, it tends to decrease. In this sense, more than 60% of the participants considered that the payment of taxes should be taken over by industry and transportation companies rather than by citizens (Figure 3). Similar results were reported in Peru, Australia, and the UK (24, 25, 46), where students tend to agree that it is the responsibility of control entities or third parties to take action to reduce air pollution. Paradoxically, in terms of responsibility in caring for children and adolescents against the effects of air pollution, our study found that 66.3% of students think it corresponds to each citizen, followed by the government, industries, and the family. These results demonstrate how people are increasingly aware of their responsibility and role as citizens in reducing environmental air pollution (47). Less than 30% of students recognize healthcare staff and scientists as key actors in protecting children and adolescents. These findings are similar to other research (48).

It was observed that 38.8% of participants knew about air quality index, and only 15.6% of those who knew about it also consulted it. These findings are similar to others (49) and higher than the 22.6% found in US adolescents without asthma (27). About knowledge of air quality alerts twice a year in their municipalities, only 31% of the participants knew about them. This is similar to the knowledge among secondary students in Mexico (42) and higher than that of U.S adolescents (19%) (18).

Two hypotheses could explain this low knowledge score of air quality alerts. First, students might perceive air quality issues as a “problem of the other,” leading to a lack of interest in and distancing of the problem (42). Second, although environmental authorities implement various strategies to address environmental problems, such as the Integral Air Quality Management Plan (PIGECA), School Environmental Projects (PRAE), and scientific citizens through the SIATA app, these efforts are not well-articulated. They do not involve a continuous and permanent process of environmental education for citizens and schools, nor have they adequately characterized the target population to effectively communicate the health risks associated with air pollution and persuade people to adopt behaviors to reduce the risks associated with exposure (14, 50).

It has been shown that when these strategies are used in schools, they increase both knowledge and awareness among students (10, 17, 51). Nuria Castell and colleagues looked at children between 6 and 12 years old in several European cities. They used the “scientific citizens” approach and found that it helped kids develop scientific projects, learn about the environment, and come up with ways to improve the air quality in their cities. Even though the effects of these strategies on the population in Colombia and our region have not been studied, the results of our study may reflect a lack of communication between environmental authorities, education authorities, and schools, and therefore, the different strategies previously mentioned have little effect on people’s knowledge about air pollution and how it affects their health. Focusing on environmental education as a permanent and long-term strategy, starting with young children and adolescents, will help people develop values and attitudes that will allow them to live in better harmony with the environment.

Our research found that being female, studying at the eighth to eleventh-grade level, attending a private school, and attending institutions where the importance of the School Environmental Project is medium in its construction and implementation were associated with knowledge scores about air pollution. The finding of low knowledge among girls was consistent in the analyses conducted with the three proxy outcomes for particulate matter pollution. It has already been documented that they have less knowledge but have and are more committed to pro-environmental attitudes, which we also found in our study (16). The fact that students with higher degrees have spent more time participating in the school environmental project may help to explain these findings by increasing their knowledge of and improving their attitude toward the issues caused by air pollution (52, 53). However, the Myers’ et.al questionnaire included a knowledge component related to atmospheric chemistry concepts, which are more likely to be present in the curriculum at higher grade levels. Furthermore, alarmingly, we found that despite air pollution being an environmental issue exacerbated twice a year in the municipalities under study, this environmental problem was not prioritized in any of the eight school environmental projects. Moreover, knowledge of air quality alerts in the municipalities showed a dose–response effect based on grade level (16), with less knowledge among students in 6th – 7th grade.

As for how the private nature of the school affects knowledge, it has been shown that in private schools that best execute the School Environmental Project, students have better knowledge but not good environmental practices (16, 54). Our study found that although increasing knowledge is associated with studying in private schools, only 11.8% of students in these institutions perceived their knowledge of air pollution as high, very similar to students in public schools (13.6%). Additionally, this contrasts with the fact that none of the three environmental school projects in private schools ranked at the highest level of importance. Other socioeconomic factors could also explain this result. Students in private schools come from households with a better quality of life, greater access to technological resources, and higher levels of education among their parents (16, 18). This was reflected in the sources used to learn about air quality, which were very different, with much more learning from teachers and the internet in public schools, and more learning from parents or social networks in private schools. Therefore, it might not only be the schools, but also the general social environment.

Other factors that were associated with knowledge were having a respiratory disease, a high attitude score and concern toward air pollution and its consequences, which is similar to other studies (19, 23, 55, 56). Contrary to what was found in our study, a study in adolescents showed that having asthma did not result in differences in the level of awareness, knowledge of the impact of air pollution on their health, and having heard about air quality alerts (27). The concern of children and adolescents about the effects of air pollution is a driving force to get more informed, accept self-imposed individual restrictions, and take action to reduce the negative effects of air pollution, as long as their needs and expectations are reflected in risk communication messages (14).

Almost all students felt some degree of concern about air pollution, a much higher percentage than in Australia (73%) (25), the United Kingdom (87%) (24), and Peru (58%) (57). This positive attitude in favor of the environment is more evident among girls, a result similar to that reported by Catalán-Velásquez et al. (42) in Mexico. They found that girls have a greater pro-environmental attitude and tend to perceive more seriously the impact of air pollution on health, leading them to engage in pro-environmental practices (16).

On the other hand, studying in a private school and having a school environmental project with high importance were associated with lower attitudes scores toward actions to reduce air pollution. Students in private schools may not perceive the air pollution or poor air quality in their vicinity (home, school) due to the economic conditions in which they live (larger green areas and less crowding conditions). In addition, the private schools included in this study had a low or medium level of importance regarding their experience in implementing the School Environmental Project. Therefore, other factors such as economic resources, lower parental education levels (18), belief in state organizations (12), self-efficacy levels regarding their actions, and environmental awareness in the neighborhoods where students live could have contributed to this outcome more than the school itself (16).

In the majority of schools in our country, the School Environmental Project is an individual project that is implemented in a fragmented manner with little institutional support in terms of teachers or financial resources, and is carried out by one or a few science professors with the assistance of some students. We believe this is the reason why most students did not integrate environmental education with their environment, practices, or habits. The School Environmental Project would have a stronger impact when it connects activities in different areas of the learning process and is considered a permanent process of multidisciplinary, comprehensive, and strategic process in the training of students, and designed, planned, coordinated, and executed by the directives themselves.

Although our study reported high awareness and concern about air pollution, not always these pro-environmental attitudes are reflected in practices and behaviors, similar to other studies (38, 42, 57, 58), which have documented this gap in non-pro-environmental behaviors in a tourism context (59). Our results contradict Quian’s et al. (60) research, in which pro-environmental attitudes are associated with good practices and pro-environmental behavior. Personal protection practices against air pollution in our study were low compared to what was found in other studies (27). Rajper et al. (26) found that 68.2% of university and secondary Chinese students used face masks. In contrast, our study found that 73.6% of participants did not use face masks and did not take other preventive measures, such as reducing the opening of doors and windows (54.1%) or avoiding leaving the house due to air pollution (58.5%). These protective mechanisms are recommended by the environmental authority in the municipalities under study and are available in the SIATA app. However, 37.7% responded that they did not know about the air quality alert system. The poor implementation of personal protection measures against the effects of air pollution could be a consequence of ineffective communication that fails to increase environmental awareness (12), as well as of the poor pro-environmental attitude (38), since attitudes and perspectives play an important role in adopting a new health behavior (14).

Despite being aware of the dangers of daily exposure to poor air quality, little implementation of practices to prevent the deleterious effects of air pollution has been reported in adolescents (18). The low pro-environmental practices could also be explained by the limited evidence on the effectiveness and safety of individual-level interventions to reduce the health impacts of air pollution due to the few existing studies and the lack of methodological standardization in assessing the intervention and outcomes (61).

Regarding medical visits associated with lower pro-environmental practices, this could be explained by the fact that doctors rarely explain that respiratory diseases can also be caused by air pollution. In adolescents with asthma, doctors explained how to limit exposure to air pollution in 12.5% of cases compared to 2.1% in adolescents without asthma (27). These results contrast with what was found in adults with respiratory diseases, where there was an association with discussing it with a health professional (prevalence ratio = 4.88, 95% CI = 3.74, 6.37) (19). Hence, it is important to strengthening medical practice with the six strategies proposed by the WHO, given its key role in promotion and prevention actions to mitigate the effects of air pollution (5).

Students had a low score of knowledge and inadequate practices scores about air pollution; however, they have higher attitude scores towards alternative solutions that could be exploited to improve pro-environmental practices. Strengthening the School Environmental Project may improve students’ KAP. However, additional studies are warranted to determine the extent to which the School Environmental Project can improve KAP.

Given the global air pollution issue and the importance of this problem for public health, studies in other regions of the country and the world are required to identify and implement tailored concrete solutions for these population groups, and to educate not only the general community but also professional and trained healthcare personnel to recognize environmental exposures and the health effects associated with them.

The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found at: https://figshare.com/ and can be accessed with doi: https://doi.org/10.6084/m9.figshare.25020563.

The studies involving humans were approved by Health Research Ethics of the Pontifical Bolivarian University. The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants' legal guardians/next of kin.

DM: Conceptualization, Formal analysis, Funding acquisition, Methodology, Project administration, Supervision, Writing – original draft, Writing – review & editing. NC: Data curation, Investigation, Writing – original draft, Writing – review & editing. VA: Data curation, Investigation, Writing – original draft, Writing – review & editing. PB: Data curation, Investigation, Writing – original draft, Writing – review & editing. MP: Data curation, Investigation, Visualization, Writing – original draft, Writing – review & editing. LO: Conceptualization, Methodology, Writing – original draft, Writing – review & editing. BM-O: Conceptualization, Resources, Validation, Writing – original draft, Writing – review & editing. JC: Conceptualization, Methodology, Validation, Writing – original draft, Writing – review & editing. LL: Formal analysis, Visualization, Writing – original draft, Writing – review & editing. ZR: Conceptualization, Resources, Supervision, Writing – original draft, Writing – review & editing.