Predicting the protective behavioral intentions for parents with young children that possess different levels of education in Hong Kong using the theory of planned behavior for air polluted with PM_2.5

Ajzen [1] created the TPB in 1991 from the Rational Choice Theory. To predict BI, the TPB is a commonly used research model [1, 2]. Fang [2] pointed out that TPB is more passive than Hines et al.’s [2] Responsible Behavior Model. However, according to Fang [2] TPB has a rigorous calculation method and has an advantage in quantitative research on predicting behavior. Therefore, this theory is suitable for marketing and health promoting policies that require accurate data [2]. The TPB has since been widely applied in the research on health management behaviors such as sex [3, 4], smoking [5, 6], alcoholism[7], and drug abuse [8]. In addition, anti-PM_2.5 behavioral intentions comprise not only health protection behaviors, but also the environmental-friendly behaviors of individuals [9]. TPB is currently one of the most commonly used theories in research studies on the interpretation and prediction of various environmental-friendly behaviors [10, 11].

As such air pollution has fast become a substantial environmental problem that can be attributed to rapid global industrialization and urbanization and has a strong negative impact on the environment and human health, particularly children [12, 13]. Contaminants such as volatile and semi-volatile organic compounds, dust, and particulate matter have seriously impacted the environment and human health. Among these, PM_2.5 are concern because with each breath that we take, the fine particles that pollute the air enter deep the into our lungs. PM_2.5 are common byproduct of car exhaust and the incomplete combustion of wood, but dust, pollen, and spores also fall into this group. The air polluted with PM _2.5 that we sometimes see in the air is largely composed of PM_2.5 pollution. Inhalation of air pollution with PM_2.5 are associated with respiratory problems, premature mortality, increased hospital admissions for heart or lung disease, acute and chronic bronchitis, and asthma [14]. As such, reducing PM_2.5 pollution should bring huge economic benefits to society and avoid/reduce human mortality [15].

The World Health Organization [16] reported that there were 3.1 million deaths globally that could be attributed to air polluted with PM_2.5 and in the EU alone, 307,000 premature deaths resulted from air polluted with PM_2.5 in 2019 [17]. Although PM_2.5 are global issue, in 2020 the 50 most polluted cities in the world based on PM_2.5 levels included 35 cities are from India, 7 from China, 5 from Pakistan, and 2 from Bangladesh and 1 from Indonesia [18]. Zhang et al.’s [19] analyses of the 33 megacities (populations > than 10 million people) based on long-term remote sensed observations indicated that the PM_2.5 concentrations did not improve between 1998 to 2018 and 452 million (M) people were exposed to PM_2.5 concentrations > 10 µg.m³, which is the WHO’s upper limit for a healthy atmosphere and 162 M people were exposed to concentrations > 35 µg/m³, which is the WHO’s non-attainment air quality threshold. Although there has been considerable work on the PM_2.5 levels in megacities and regions of the world where air pollution is a big problem, PM_2.5 can impact the air quality anywhere in the world and we’d be remiss to preclude the human health impacts of PM_2.5 air pollution from anywhere in the world.

The reduction of PM_2.5 contributions and protection against air polluted with PM_2.5 has become the focus for governments and the public at large [20]. Environmental problems in Hong Kong are mostly focused on the management and less on understanding environmental behaviors. In other words, the reactions and responses of citizens and their behaviors on environmental issues rather than their literacy or understanding of environmental issues. Therefore, in this study we focused on understanding how citizens responded to air pollution concerns, especially how parents with young children and with different levels of education responded or reacted when their children were exposed to air polluted with PM_2.5. Children are one of the most sensitive receptors and short-term exposure to air polluted with PM_2.5 can trigger asthma, requiring hospitalization [21], and younger children are more likely to be affected than older children [22].

Although studies on behaviors reducing or avoiding with PM_2.5 have been explored from the perspective of the family [9], studies on the behavioral and health management elements related to protection against or avoiding air polluted with PM_2.5 are lacking. We believe that the pathways that influence human behaviors that avoid or minimize exposure to PM_2.5 is an ideal topic to study in more detail. In addition to reducing and controlling exposure to air contaminated with PM_2.5, it was also important to understand the elements that generated the protective behaviors to avoid exposure to air polluted with PM_2.5. As such we focused on parents with young children with different levels of education that were living in Hong Kong. We also considered the parent’s health concerns and the hazards associated with exposure to air polluted with PM_2.5.

There is a correlation between economics and education level [23], which suggests the relationship between education and behavior is important and cannot be ignored [24]. Consequently, better understanding of the role that the level of education plays in shaping people’s behaviors towards avoiding air polluted with PM_2.5 was considered important because this type of analysis has not yet been performed. Furthermore, education levels are related to a person’s AT, which are then affected by their SN [25]. Therefore, we hypothesised that the parent’s level of education affected their SN positively. To understand parental behaviors related to avoiding air polluted with PM_2.5, we assessed the protective behaviors of parents with young children with different levels of education living in Hong Kong. The dimensions that shape protective behaviors included: (1) attitudes (AT), (2) perceived behavioral controls (PBC), and (3) subjective norms (SN). The TPB model emphasizes controlled aspects of human information processing and decision-making that is concerned with goal-oriented behaviors and behaviors that are guided by a conscious self-regulatory process. AT is the intervening variable of SN and BI because a person’s AT can affect their BI directly or indirectly through their SN [26‐31].

The use of this model may help explain the relationship between social psychology and people’s preventative behaviors related to environmental problems. Despite the plethora of studies assessing the toxicity and impact of air polluted with PM_2.5 on humans and the environment, work on the factors that influence people’s behaviors such as AT and SN towards avoiding air polluted with PM_2.5 is lacking [12]. From the perspective of TPB, people find that even when accounting for the predictive variables in TPB, understanding past behavior(s) can help predict future behaviors [1]. SN are most weighed in predicting an individuals' willingness to reduce emissions that contribute to air pollution, but the best way to motivate people to reduce air pollution may be to exert social pressure or create a people-friendly atmosphere and environmental protection activities [32]. The use of the TPB model with Hong Kong’s societal norms and values indicate subjective regulations may be the most important contribution for people to reduce air pollution emissions. Therefore, we tested the following hypotheses (Fig. 1).

We received 301 responses from the undergraduate group and 109 responses from the post-graduate group. The Cronbach α of the AT (Table 1), SN (Table 2), PBC (Table 3), and BI (Table 4) variables for questions posed to the parents of both groups support the reliability of the questions and responses of questionnaire responses [43]. Cronbach α is a measure of the internal consistency or reliability of questions that are based on a Likert scale. The Cronbach α value of the questionnaire was 0.928, which exceeds the 0.7. Values above 0.7 are considered good.

Using the TPB framework, we conducted a survey to understand how AT, SN, and PBC affect the protective behaviors of parents from both groups with respect to air polluted with PM_2.5. The results were then mapped using a SEM to better understand the relationships and paths between AT, SN, and PBC based on the behavioral differences of the parents from both groups. Of the 12 hypotheses tested, the results supported 3 (H2a, 5a, and 6a) for undergraduate group and 5 the post-graduate group (H2b, 3b, 4b, 5b, 6b). The difference between both groups is that there are more paths between AT and AI in the post-graduate group compared to the undergraduate group.

The results indicate the SN and BI scores of the undergraduate group are statistically higher than the post-graduate group, but there were no statistically significant differences in the AT and PBC of both groups. Similar results between parents with different education levels and behavior are known too [46]. Table 9 shows the comparison of the results of parents with different levels of education.

In this study we assessed the factors that influence the air pollution prevention and avoidance behaviors associated with air polluted with PM_2.5 for parents in the undergraduate and post-graduate groups. Our results show the AT, SN, PBC and BI used in the air pollution protection model for the parents of both groups are connected by separate pathways. The undergraduate group has a higher PBC compared to the post-graduate group and because the SN associated with their social ecosystems contribute to their BI. These findings are important because we can predict the protective BI for parents with young children that possess different levels of education in Hong Kong using the TPB for air polluted with PM_2.5.

Using a path analysis tool, we revealed that the undergraduate and post-graduate groups had different BI paths. The BI path of the undergraduate group is purer and simpler when compared with the path of the post-graduate group: only three (H2a, 5a, 6a) of the six hypotheses (H1a, 2a, 3a, 4a, 5a, 6a) in the undergraduate group model forming a single path AT-SN-PBC-BI. The PBC in the undergraduate group form based on the SN around them, which ultimately contributes to their BI to the protective behavior. Meanwhile, in the post-graduate group model, the six hypotheses including H2b, 3b, 4b, 5b, 6b are statistically higher scores, which forming paths including AT-SN-PBC-BI, AT-PBC-BI and AT-SN-BI. But there is no path for AT-BI (H1a, 1b) in both groups.

In this study, AT which ultimately contributes to their SN in both groups more than contributes to the PBC and BI in the study. These findings are important because AT cannot affect BI that means attitude itself cannot affect protective behavior associated with PM_2.5 air pollution directly. The air pollution prevention BI model of parents from both groups forms paths models that vary in complexity. Our results clearly distinguish the different path models between the parents of both groups.