1. Introduction
Municipal solid waste is one of the most serious problems confronting developing countries due to the conflicting development goals between rapid urbanization and the persistent craving for a cleaner environment. As one of the major sources of municipal solid waste, the increasing generation of household solid waste (HSW) has led to multitudes of environmental hazards such as waste siege, environmental degradation, water and soil pollution, and negative impacts on the quality of human life [
1], to which most costs of municipal waste management are allocated [
2]. Waste source separation is a critical component of a successful waste management system [
3]. Besides this, it also is one of the most effective and economic ways to enhance the reuse and recycling rate of waste and to guarantee the quality of waste for the final disposal. The implementation of waste separation policy depends on the change of residents’ waste disposal habitual behavior. Some developed countries, such as Germany, UK, and Japan, have achieved success through 20–30 years’ cultivation of public environmental awareness by social campaign and legislation. In contrast, the amount of garbage is rapidly increasing in many developing countries due to the rise of living standards and urbanization. On the other hand, because of the differences between urban and rural areas, lower income and lower educational level, and poor facilities of waste separation, the waste separation policies face great challenges. There is no doubt that the success of waste separation policy is strategically important for alleviating resources and sustainable development for them.
As the largest developing country, China has become the world’s largest waste producer since 2004 [
4] and the volume of waste removal has reached 228.02 million tons in China in 2018 [
5]. Two-thirds of cities in China suffered “waste siege” [
6]. Based on the experience of waste separation in eight cities since 2012, China launched a new mandatory waste separation campaign for 46 cities in 2018 by local-government-led campaign with a huge investment of resources along with legislation and management regulations [
7]. The Ministry of Housing and Urban-Rural Development of China has set the goal of improving household waste management, with an implementation of mandatory separation of household solid waste in 46 cities, aiming at the recycling rate of household solid waste to exceed 35% by 2020. With an initial success after one year [
8], this policy is expanding to 220 cities and rural districts in 2020.
However, in order to further facilitate and improve the waste separation program countrywide, several issues need to be addressed. Firstly, it is expensive to maintain the waste separation program because it requires a significant involvement from community officials, sanitation workers, and volunteers to participate and supervise. Secondly, the accuracy and participation rate of waste separation is still low in many cities in China. The project of waste separation in some communities did not yield a positive outcome after a period of processing time due to the lack of residents’ engagement. It may be that some communities only focus on the publicity but ignore the importance of the residents’ commitment or effective supervision [
9]. Thirdly, it is still in question if the experience of waste separation policy in the pilot areas can be generalized. The vital factor that determines the sustainability of the waste separation problem is residents’ participating behavior. As individual behaviors are mainly affected and dominated by psychological factors, it is necessary to identify the internal and external factors accountable for waste separation behavior. Little empirical studies have investigated resident perception and beliefs that are related to waste separation behaviors from a solid theoretical perspective.
The theory of planned behavior (TPB) is widely used to explain behaviors over which people may have limited volitional control [
10]. The TPB argues that behaviors stem from individual perceived behavioral control and intention; then, the behavioral intention depends on three direct predictors, which include attitude, subjective norm, and perceived behavior control [
11]. Attitude toward the behavior refers to the extent of an individual’s positive or negative evaluation of behavior in question. Subjective norm is a person’s perceived social pressures on whether to perform a particular behavior. In addition, a person’s perception of how easy it is to perform can affect whether they are willing to perform it. Therefore, perceived behavioral control is the direct antecedent of behavior, and it predicts and explains intention. It explains human behavior and allows researchers to identify the determinants of environmental behavior and subsequently target these factors in interventions [
12].
However, the applicability of TPB to predict pro-environmental behavior requires further examination. First, the completeness and efficiency of the TPB for predicting pro-environmental behavior not only depends on three direct predictors: attitude, subjective norm, and perceived behavioral control, but also is influenced by behavioral, normative, and control beliefs that commonly called indirect predictors [
12,
13]. When performing a behavior, the belief associated with the behavior in question is activated, which is called salient beliefs. Fishbein and Ajzen argue that such beliefs are important for behavioral intervention; by changing the salient beliefs, it should be possible to change global attitudes and intentions, and in turn, influence actual behavior [
14]. These beliefs contain outcomes (behavioral beliefs), social pressures (normative beliefs), and facilitating/inhibiting factors (control beliefs) associated with household separation behavior. The assessment of indirect predictors requires a qualitative exploration of factors that influence a given behavior because these beliefs vary from one context to another [
15]. The previous research on waste separation behavior has largely overlooked underlying beliefs that eventually affect resident behavior.
Second, the TPB, as a rational-choice model, has been criticized for neglecting moral consideration, and the correlation between attitudes and intention in waste separation and recycling behavior has been questioned [
16]. Residents do not participate in recycling behavior, even if they have high environmental attitudes and values [
17,
18]. White et al. also emphasized the “attitude-behavior gap” in the review of sustainable consumer behavior [
19]. Although Ajzen and Fishbein abstain moral considerations [
20], in the interest of the collective good, moral beliefs significantly contribute to the understanding of intention [
21]. Waste separation behaviors require the individual to restrain egoistic tendencies for collective interests [
22]. Stern et al. suggest that one such motive of environmental protection is provided by a judgment that pollution is, to put it bluntly, morally wrong [
23]. The beliefs about how environmental hazards should be handled are based on moral judgments made by residents or organizations producing hazardous substances or regulating their use and disposal. Therefore, Kaiser and Scheuthle found that TPB should be extended into the moral domain to improve the explanatory power for conservation behavior [
24].
Third, previous studies also indicated that the subjective norm component of the TPB framework rarely contributes to the prediction over and above the effects of attitude and perceived behavioral control [
25,
26]. Poor measurement or overly narrow conceptualization of the subjective norm component may account for its lake of predictive validity. Armitage and Conner argue that the normative component includes both an internally reliable measure of subjective norm and a measure of self-identity [
26]. Self-identify is defined as the salient part of the actor’s self that relates to a particular behavior. It may be regarded as the extent to which the actor sees him- or herself as fulfilling the criteria for a particular societal role. Self-identity reflects the internalization of external norms, which is another important psychological mechanism to explain the pro-environmental behavior [
27].
Accordingly, this study integrates existing conceptualization and findings into an extended TPB framework, which incorporates the underlying beliefs, extended self-identity, and moral norm in predicting waste separation behavior (
Figure 1).
In addition, previous studies also suggested that waste separation behavior is affected by social and demographic variables. In the context of China, where this study is conducted, rural-urban differences mean the differences in residential type, age structure, incomes, and educational level. With the development of China’s economy, rural young people have been converging to cities over the past decades. This has led to a large proportion of elderly people in rural areas [
28]. Meanwhile, the difference in employment opportunities makes many people with a high educational level choose to stay in the cities. It has also led to higher incomes for urban residents [
29]. On the other hand, due to differences in social policies and space constraints, rural residents are more likely to live in bungalows, and urban residents are more likely to live in apartments. All of these factors contribute to differences between urban and rural residents in terms of waste separation behavior. Considering this program has also been tried in the rural district, our research investigated urban residents’ and the rural dweller’s household waste separation behavior simultaneously and discussed the differences in their waste separation behaviors. Therefore, the following research questions were developed for this study.
What is the relationship between beliefs and psychological factors (attitude, subjective norm, and perceived behavioral control)? Can the TPB predict the residents’ waste separation behaviors?
Which factors have a significant effect on household solid waste separation behavior? To what extent do these factors predict waste separation behavior?
How do urban and rural waste classification behaviors differ?
In this study, in order to comprehensively understand the psychological mechanisms and external factors of household waste separation behavior, we integrated the direct predictors and indirect predictors of attitudes, subjective norms, perceived behavioral control, and extended moral norms and self-identity into TPB model, to examine the relationship between psychological factors and resident’s waste separation behavior. Presented in the following sections, we first described the methodology and conducted the data analysis, and then, the results of this study provide theoretical support for the policy formulation of urban and rural household waste separation programs in China. Finally, we posted the conclusions and pointed out management implications, research limitations, and future research directions.
3. Results
3.1. Descriptive Statistics
About 1300 questionnaires were distributed by home visit in the first survey, then the questionnaires were collected after 30 min. We received a total of 941 questionnaires fully completed. In the second step, we got in touch with the participants by telephone to finish the second part of the survey. Finally, only 604 respondents (N
urban = 307; N
rural = 297) were considered valid after completing both surveys (The original data is placed in
Supplementary Materials (Table S1)).
Demographics (
Table 2) consist of gender, age, education level, and monthly household income. The study uses family income as the indicator of income level because the income of most Chinese family members is shared with other family members [
37]. The demographics show that rural residents are older than urban residents and that urban residents have higher education and household income than those of rural residents. This reflects the actual demographic characteristics of residents in urban and rural areas that were surveyed [
38].
3.2. Reliability and Validity
Reliability, also known as consistency, is the ability to give nearly identical results in repeated measurements under identical conditions. Cronbach’s α and composite reliability (CR) as reliability indicators are shown in
Table 3. All of the reliability indicators are higher than 0.8 in the urban and rural samples, which indicates that each variable exhibited strong internal consistency.
Standard factor loadings and average variance extracted (AVE) were used in the analysis of convergent validity. Standard factor loadings ranged from 0.689 to 0.955 in the urban samples (from 0.674 to 0.974 in the rural samples). The AVE ranged from 0.692 to 0.874 in the urban samples (from 0.650 to 0.893 in the rural samples). All the indicators met the criteria of factor loadings as they were above 0.7 [
39], and the average variance extracted exceeded 0.5 [
40,
41,
42].
Discriminant validity refers to the difference between a construct and the other construct [
39]. Generally, the square root of the AVE should be greater than the inter-construct correlation [
43]. The matrix of correlation and the square root of AVE confirm the better discriminant validity in the urban and rural samples (
Table 4 and
Table 5).
3.3. Analysis of Behavioral, Normative, and Control Beliefs
The relationship between indirect variables (beliefs) and direct variables (psychological variables) elicited in the pilot study was estimated using linear regression (SPSS 26.0). The results are shown in
Table 6.
In both cases, the four behavioral beliefs account for the variance in attitudes (39.0% and 33.2% for urban and rural residents, respectively). In all the beliefs, environmental protection was the dominant determinant of attitude. Otherwise, the beliefs of social progressing are only significant in predicting attitudes in urban residents, and the beliefs of earnings to attitudes are supported only in rural residents.
The seven normative beliefs accounted for 30.5% of the variance in subjective norms in urban residents and 82.2% in rural residents. The belief components account for considerably more of the variance in rural residents’ subjective norm than urban. Analysis of normative belief components revealed that subjective norm of rural residents is principally determined by the normative beliefs from families, friends, relatives, neighbors, Chinese Communist Party (CCP) members, and government. In contrast, the urban residents’ subjective norms can only be influenced by the references of families, CCP members, and government. CCP members and family were shown to exert the greatest influence on both cases. The cleaners and community managers are ineffective in promoting household waste separation to residents in both urban and rural residents.
The control beliefs account for 40.4% (81.2%) of the variance in perceived behavioral control in urban (rural) residents, which means that control beliefs play an important role in residents’ behavioral control, especially for rural residents. The estimated results about control beliefs indicted that the control factors of knowledge and convenience have positive effects for predicting perceived behavioral control in both rural and urban residents. The effects of time and publicity are only significant for urban residents, and the control factors related to money, including providing waste bin or bag and fine, only affect rural residents’ perceived behavioral control.
3.4. Extended TPB Analysis
The extended TPB model was estimated using Structural Equation Modeling (SEM, Amos 24.0) in this study. Goodness-of-fit indices evaluate whether the hypothetical path analysis model and the collected data are compatible with each other. The model fit of the overall structural equation modeling is a great indicator to predict model quality. Path coefficients, standard errors, and their significance for the integrated model are presented in
Figure 2. The results suggest a good fit for the SEM model.
In the urban sample, χ
2urban = 582.870, χ
2/DF
urban = 3.389, CFI
urban = 0.931, GFI
urban = 0.852, IFI
urban = 0.932, RMSEA
urban = 0.088. In the rural sample, χ
2rural = 407.184, χ
2/DF
rural = 2.367, CFI
rural = 0.966, GFI
rural = 0.878, IFI
rural = 0.966, RMSEA
rural = 0.068. All of the model fit indicators are higher or closer to the relevant evaluation criteria [
44], which suggests that the two models achieved a good fit to the data. The two models and their results were shown in
Figure 2a (urban) and
Figure 2b (rural).
Based on the results, the percentage of explained variance (R2) of intention and behavior is 57.3% and 65.5% in urban residents, while it is 76.6% and 68.7% in rural residents. It shows that extended TPB can effectively predict household solid waste separation behavior in both urban and rural residents. In the prediction of waste separation behavior, the intention plays most crucial role in both urban and rural groups (rurban = 0.826, p < 0.001; rrural = 0.544, p < 0.001); however, the another predictor of behavior, perceived behavioral control, is significant only in the rural group (rurban = −0.041, p = 0.619; rrural = 0.324, p < 0.001). In addition, in the three original variables in TPB, the subjective norm (rurban = 0.118, p = 0.014; rrural = 0.468, p < 0.001) and perceived behavioral control (rurban = 0.158, p = 0.036; rrural = 0.311, p < 0.001) have effective impacts on waste separation intention, but the path from attitude to intention was not supported in both urban and rural models. Besides this, the moral norm and self-identity as the extended factors was tested in the integrated model, which shows that the self-identity are positive to intention of waste separation in both models (rurban = 0.361, p < 0.001; rrural = 0.235, p = 0.002), while the moral norm are only supported in the urban model (rurban = 0.209, p = 0.028; rrural = −0.058, p = 0.430) based on the SEM results. Overall, it is shows that the normative psychological variables, including subjective norm (rrural = 0.468, p < 0.001) in the rural model and its internalized factor, self-identity (rurban = 0.361, p < 0.001), as well in the urban model, play a key role in residents’ HSW separation behavior.
5. Conclusions
In summary, the present study found support for using the extended TPB to predict intention and behavior regarding HSW separation. First, contrary to the previous researches with TPB that attitudes are the most decisive predictor of behavioral intention, this study finds that attitude cannot predict HSW separation intention in both urban and rural groups. Meanwhile, the moral norm, as the complement of attitude, contributes to the interpretation of waste separation intention in urban residents. Second, the expanded conceptualization of the subjective norm component improves the predictive power. The subjective norm and self-identify proved to be the principle psychological factor on the intention of HSW behavior. As for the beliefs, family and CCP members have the most social influence in both urban and rural residents, while the secondary factor is government influence in the urban group and neighbors influence in the rural group. Third, the perceived behavioral control has a direct effect on intention in both urban and rural groups, but the direct influence on HSW separation behavior is only in the rural area. In terms of control beliefs, except for some control factors that affect both urban and rural residents (like knowledge and convenience), rural residents are more sensitive to money-related factors (free waste bin/bag and fine).
The study provides a series of intervening policy for community and government. First, providing information about common responsibility and moral meaning in brochures and mass media advertisement is a good strategy, because moral norm is an important psychological driving force to promote their behavior. Second, CCP members are key in providing modeling of recommended behaviors. In China, the CCP members are also seen as block leaders. The communities, especially in rural areas, let the CCP member play a pioneering role through various techniques. In the countryside, it is effective to set up a group with CCP members as the center to conduct collective assessment to promote waste separation. Lastly, monetary rewards may serve effectively for rural residents, and the local government and community could use material incentives to initiate repaid changes in residents’ waste separation behavior, such as providing free waste separation bins and waste bags. However, for urban residents, the community managers should consider more about situational factors that will facilitate or inhibit waste separation behavior, such as the distance from the house to garbage room, setting clear identification of waste separation on site, and providing more feedback about their waste separation behavior.
Although this research has several significant contributions, such as the use of the division of belief structure, the actual behavioral measurement, and comparison of urban-rural differences, it also has some limitations that need to be focused on in future research. First of all, some specific beliefs, like resource conservation and feedback, are contrary to previous research results. These beliefs should be tested and analyzed individually by the laboratory or field experiments in future studies. Further, we used self-reports for measuring actual behavior according to Ajzen’s recommendation [
31]. However, self-reporting may bias the authenticity of the data. Future research should use other methods, such as measuring the number of different types of waste recycled, to find the actual waste separation behavior. Moreover, this study discusses the urban-rural differences in HSW separation, but the regional differences, such as developed/developing economies and cultural differences, are unclear. This also requires follow-up research.