Research on the Impact of Event Sustainability on Brand Equity in Event Activities: A Case Study of Hainan Expo

: This study investigates sustainability practices from the event participants’ perspective. Taking the China International Consumer Products Expo as a case study, this study adopts a quantitative research method to examine the effects of the sustainability practices of events on brand equity via structural equation modeling. The results of the empirical analysis are as follows: (1) the sustainability practices of events is a multi-dimensional concept, and the four determinants of sustainability practices of events examined in this study are environmental sustainability practices, economic sustainability practices, social sustainability practices, and policy sustainability practices; (2) the four dimensions of sustainability practices have positive effects on brand image; (3) social sustainability, environmental sustainability, and policy sustainability practices have a positive impact on willingness to pay a price premium; (4) brand image and attendees’ willingness to pay a price premium are signiﬁcantly related to brand loyalty. The ﬁndings will be useful not only in improving the new structure of sustainability in the event ﬁeld but also in providing new ideas and new ways for event organizers to improve event brand equity.


Introduction
The event industry is a new platform that offers high added value and knowledge innovation. It plays a vital role in the growth of regional economies and the optimization of industries. However, during the outbreak of COVID-19 in recent years, the event industry has experienced many challenges. Many event companies have been forced to think about the future development path of the event industry while transforming their activity formats to achieve long-term sustainable development. The concept of sustainable development is the core element of the scientific development concept in China. Although it has received attention from people from all walks of life in China, the event industry still has an ambiguous understanding of the sustainability of event activities. Fortunately, in recent years, both the government and industry institutions have made concerted efforts to address this issue. In particular, the State Council's "Guiding Opinions on Accelerating the Establishment and Improvement of a Green, Low-carbon, and Circular Development Economic System" (NDRC (2021) No. 4), issued on 22 February 2021, included a call in its sixth article to "improve the level of green development in the service industry". The opinions also laid out specific requirements for the green development of event activities, which included "promoting green development of the event industry, guiding the formulation of relevant green standards in the industry, and promoting the recycling of event facilities". To this end, on 10 July 2022, the China State Council approved the construction of national sustainable development agenda innovation demonstration zones in Huzhou, Xuzhou, Ordos, Zaozhuang, and Hainan Tibetan Autonomous Prefecture.
Since the United Nations introduced the concept of "sustainable development" at their General Assembly in 1987, research on sustainability has been conducted worldwide across various sectors. Currently, both national and international understandings of sustainability revolve around the "triple bottom line (TBL)" which includes economic, environmental, and social sustainability [7][8][9][10][11]. When the concept of sustainability is applied to the event industry, most research draws on studies based on the tourism industry. However, just as the tourism industry emphasizes the need to develop sustainability specific to the industry, rather than simply applying measures from other sectors, the unique characteristics of the event industry must also be considered when constructing the concept and dimensions of sustainable event activities [12]. A review of the relevant research from the last 15 years revealed that neither domestic nor international research on sustainable event activities has reached maturity. Due to inconsistent terminology and a lack of theoretical research, there is still no agreed definition of sustainability in the event industry. Most studies adopt either the United Nations General Assembly's 2005 definition, "meets the needs of the present without compromising the ability of future generations to meet their own needs" [13], or the United Nations Environment Program's 2012 definition, "organized and implemented activities that minimize potential negative impacts and leave beneficial legacies for the host community and participants" [14], or the ISO 20121 sustainable event management system's definition, "the degree to which sustainable development is achieved within an organization or a large event context" [15].
The academic study of the dimensions of sustainability is constantly evolving. In the early stages, the understanding and evaluation dimension of sustainability primarily focused on the environmental aspect, and many people equated "green events" with "sustainable events." They used terms that described the environment to refer to sustainability, such as "Green Meeting" or "environmentally friendly events" [1,2]. However, in their research, Han et al. (2015) explicitly stated that sustainable events and green events are two independent concepts [16]. In recent years, compared to domestic research on the sustainability of event activities, which still focuses on the environmental aspect, the social aspect has received more attention from foreign scholars [4,17]. In addition, the economic aspect mainly refers to "development," while sustainability mainly refers to "the environment." The goal of sustainable tourism or events should be to alleviate the conflict between economic development and environmental protection [18]. This is because on the one hand, focusing solely on economic sustainable development is essentially unsustainable, and on the other hand, placing too much emphasis on environmental factors can sometimes harm other aspects of sustainability. Economic impacts can lead to environmental and social impacts, and vice versa [19]. Therefore, social, economic, and environmental aspects should be the three interwoven components of sustainable development, and none can be dispensed with [9,20].
It is worth noting that compared to other fields, the successful implementation of event activities is heavily reliant on the support of stakeholders. Therefore, event organizers must establish and maintain close relationships with stakeholders to obtain support [21][22][23]. In addition to the organizers, stakeholders in event activities also include professional audiences, general audiences, exhibitors, governments, event associations, and communities, all of whom play important roles in the sustainable hosting and development of event activities. Kim et al. (2022) noted that government policies supporting event activities can lower the risk of activity failure and promote the smooth execution of events [24]. In China in particular, the rapid development of the event industry in recent years cannot be separated from the support of relevant policies. Therefore, policy factors have played an important role in the development of China's event industry [25][26][27], but empirical research that incorporates policy factors into sustainable event activities is still relatively scarce.
In summary, based on the definition of sustainable development proposed by the United Nations Environment Program 2012 and the definition listed in the ISO 20121 event sustainability management systems, the concept of event sustainability in this study refers to organized and implemented event activities that ensure local economic interests, environmental protection, social harmony, and particular policy support. The measurement dimensions follow the principle of multidimensionality, measuring sustainability from four dimensions: economic, social, environmental, and policy sustainability. Specifically, in this study, economic sustainability practices refers to organized and implemented event activities that support national and regional economic interests by promoting the local tourism economy, balancing off-peak seasons of the local economy, providing new business opportunities, and creating additional jobs; environmental sustainability practices refers to organizing and implementing event activities that minimize potential negative pollution in host cities' environments, including reducing light pollution, noise pollution, garbage from event activities, and air pollution, as well as promoting reusable materials and green concepts; social sustainability practices refers to organizing and implementing event activities that reduce potential negative impacts and promote local social harmony by reducing the crime rate, providing diverse leisure options, and promoting cross-cultural communication; and policy sustainability practices refers to the provision of special policy support by local governments for organizing and implementing event activities.

Brand Equity
Scholars have focused on two main viewpoints when studying brand equity. The first emphasizes the financial perspective, describing the direct value generated by the tangible or intangible assets of a brand. The second viewpoint is consumer-centered, stating that brand equity depends on the differences in consumers' reactions to brand marketing before and after obtaining the brand's product; this reflects the value added or reduced by the product and is reflected in consumers' perceptions, preferences, and behavior towards brand marketing [28,29]. As the consumer-centered viewpoint of brand equity can reflect consumers' familiarity, love, or care for a particular brand and generate a special impression as the level of concern for the brand increases [30], it can also explore consumers' behavioral intentions toward a brand; this consideration has attracted a great deal of attention from the management and service fields in recent years. The aim of this study is to explore the impressions, values, and preferences of event participants towards the event brand, focusing on the consumer-centered perspective of brand equity.
A review of the literature measuring brand equity from a consumer-oriented perspective revealed that most such studies are based on Aaker's (1996) and Keller's (1993) measurement models, which have been continuously revised in combination with practical situations in different fields. Netemeyer et al. (2004) conducted a survey of more than 1000 consumers across sixteen different brands in six product categories to explore the relationship between customer-based brand equity (CBBE) and actual brand purchasing behavior [31]. The study resulted in a model connecting organizational associations, brand image, willingness to pay a price premium, and brand purchase behavior through empirical analysis. In their study, brand associations refer to a consumer's belief that the brand company is honest, trustworthy, and cares about its customers, while brand image is perceived by consumers as the degree to which a brand is believed to have a rich heritage/history and consistent positive image; willingness to pay a price premium is defined as the amount customers are willing to pay for their chosen brand compared to other brands of the same size/quantity, and this model has also been modified and adopted by multiple researchers. Therefore, to explore the implications and dimensions of sustainable event brand equity perceived by event participants, it is important to combine the characteristics of sustainable event participants, analyze their perceptions regarding sustainable event activities, and evaluate their willingness to pay a premium and loyalty to event brands that embody sustainable development concepts.

Theoretical Foundation
An increasing number of people are beginning to pay attention to the environment; thus, consumers will be more loyal to a brand if they believe it is sustainable [32]. The growing awareness of sustainability issues has rendered sustainability an important consideration when choosing a brand from a consumer perspective [32]. The equity of a brand can be measured before and after the brand is considered sustainable; therefore, sustainability can be viewed as a predictor of brand equity. Nguyen et al. (2015) suggested that sustainability and social responsibility help to explain finance-based brand equity [33]. Sustainability orientation was also found to have a strong influence on the performance of SMEs in terms of brand association and brand loyalty [34].
In the context of tourism, sustainable tourism is defined as "The tourism practices that take the present and future impacts into consideration of the environmental, economic and social aspects while fulfilling needs of the guests, industry, environment, and host communities" [35]. Sustainability is becoming increasingly important in improving the quality of the tourism experience and the overall satisfaction of tourists. The rising expectations of responsible behavior from shareholders, employees, and tourists have led to environmentally sustainable strategies such as pollution prevention, energy efficiency, renewable energy, etc. [36]. Shanti and Joshi (2022) found that environmental sustainability helps hotels to build sustainable brand equity [37], and presented a successful brand image for hotels involved in sustainable branding.
In theory, sustainability is an all-encompassing, ever-evolving concept that involves many factors. Existing research on sustainability often focuses on one sole aspect of the "triple bottom line" and tends to adopt an impact-focused approach [38]. In the event industry, we believe that government policies play a very important role in the construction of event brand equity. Therefore, in this study, we assume that all three dimensions of the "triple bottom line" and policy sustainability help to build brand equity.

The Impact of Sustainability on Brand Equity
Reviewing the literature from the past decade, we found that there are few studies on the relationship between sustainable practices and brand equity, although some brand asset researchers have recognized that incorporating environmental concerns into products can increase their competitive strength [39][40][41]. For example, in the hotel industry, Trang et al. (2019) extracted the attributes of green hotels through in-depth interviews and a pre-survey of green hotels in Vietnam, and then conducted empirical research on hotel guests to construct five dimensions (customer benefits, water efficiency, energy efficiency, green features, and recycling policies) and a 24-item list of green hotel attributes. The results showed that the stronger the perceived green hotel attributes, the more evident the guests' attitudes towards supporting the environment [40]. To verify the hotel guests' views of eco-friendly decisions, Han et al. (2019) conducted an on-site survey of 289 hotel guests. They constructed a green management performance model consisting of three dimensions (reducing recycling and waste, saving water, and saving energy) through structural equation modeling and explored its relationship with hotel guest behaviors. The results showed that the stronger the guests' perception of green performance, the greater their loyalty [42]. In addition, to investigate whether the green development of hotels can shape their brand image, researchers analyzed 400 guests staying in green hotels, exploring their perceptions of green behaviors and brand equity, and found that guests' perceptions of green brand image, green brand awareness, and green perceived value have positive effects on green brand equity [41]. Furthermore, researchers found that the stronger the consumers' recognition of the seriousness of environmental issues and the importance of environmental protection, the greater their willingness to purchase green products and services [42][43][44]. For example, Wang et al. (2022) examined consumers' willingness to pay for food labeled "green food" and found that consumers will pay higher prices for environmentally conscious products [44]. Therefore, environmentally conscious consumers are more loyal to and likely to purchase products from brands that practice sustainable concepts. With these considerations in mind, this study proposes the following hypotheses: Hypothesis 1a. Environmental sustainability practices significantly influence the brand image of event activities.
Hypothesis 1b. Environmental sustainability practices significantly influence willingness to pay a price premium.
Research conducted over the past decade has shown that holding event activities can generate significant economic benefits by boosting other industries, increasing tax revenues, expanding consumer spending, promoting local employment, attracting investment, and contributing to regional development. These factors are used to measure economic sustainability indicators [10,12,16]. While environmental sustainability research has produced consistent results, studies on economic sustainability and its impact on brand equity have demonstrated inconsistent findings. To investigate whether sustainability information has a maintenance effect on brand image, Erdil (2013) conducted a qualitative analysis of sustainable development activities involving the top three brands in the Turkish home appliances industry. The author determined that commercial sustainability comprises environmental, social, and economic sector actions, which act as determinants of brand knowledge and perception and collectively construct a brand image. In other words, sustainable actions related to the economic, environmental, and social sectors can play an important role in maintaining brand image [45]. Meanwhile, Choi and Ng (2011) studied the effect of economic and environmental sustainability on consumers' evaluation of decoration companies and their willingness to purchase products. The results showed that high-level economic sustainability is more likely to trigger consumers' positive evaluations and willingness to purchase than low-level economic sustainability. Conversely, low-level economic sustainability is more likely to trigger consumers' negative and passive evaluations and willingness to purchase the company's products [46]. This indicates that customers exhibit a positive attitude and payment behavior towards a company's economic sustainability. By contrast, Hussain et al. (2017) conducted a content analysis of the sustainable development reports of 100 American companies to identify the relationship between sustainability and financial performance. The results showed that the economic sustainability dimension, which includes direct economic efficiency, market share, and indirect economic impact on society, has no significant direct impact on, but rather a weak correlation with financial performance. However, the environmental and social dimensions have significant impacts on financial performance [47]. Therefore, this study considers that the economic sustainability of event activities is an important influencing factor for brand image and willingness to pay. In summary, this study proposes the following hypotheses: Hypothesis 2a. Economic sustainability practices significantly influence the brand image of event activities.
Hypothesis 2b. Economic sustainability practices significantly influence willingness to pay a price premium.
Social sustainability primarily refers to the connection between event activities and the local community or the residents' living environment. Whether residents are positively or negatively impacted by event activities can affect their perceptions of the brand connected to the event [9,48]. For instance, if a large event creates issues like traffic congestion, criminality, noise, or impacts the locals' quality of life, or residents experience feelings of the destruction of their way of life or a loss of identity due to the arrival of tourists, this might create negative impressions of the event or its organizers and lead to the rejection of future events [49]. Conversely, a higher perception of social sustainability can benefit the brand and enhance its value. For instance, Lin et al. (2019) collected data from 316 customers of the Come True Coffee brand and used a structural equation model to verify the relationship between the company's social mission, service quality, and brand image. The results showed that the company's social mission effectively improved customers' perceived service quality and brand image [50]. Additionally, some studies conceptualize corporate sustainability as corporate social responsibility and empirically analyze the direct relationship between CSR behavior and corporate performance. For example, in a study conducted by Madueño et al. (2016) on small-and medium-sized enterprises in Spain, the authors successfully verified the relationship between CSR behavior and corporate performance. They concluded that CSR activities, such as environmental initiatives, employee benefits, and local community benefits, can enhance a company's worth and competitive edge. They found that CSR initiatives can also significantly promote other corporate performance indicators, improving the company's image, profitability, sales, and customer satisfaction [17]. Importantly, their study also revealed that consumers who witness CSR behavior contribute more to corporate performance indicators such as company image and profitability than those who do not witness such behavior. Therefore, event activities perceived by primary participants as socially sustainable can improve a brand's image and lead to a greater willingness to pay for future events.
Hypothesis 3a. Social sustainability practices significantly influence the brand image of event activities.
Hypothesis 3b. Social sustainability practices significantly influence willingness to pay a price premium.
Although relevant policies are crucial to an event industry's development, foreign research mainly focuses on analyzing policy factors related to choosing event destinations, while domestic analysis of policy factors only concentrates on theoretical and qualitative research, with a focus on funding subsidies and policy recommendations [26]. Consequently, there is a lack of relevant empirical research. For instance, Draper et al. (2011) found that conference planners prioritize a conference destination's sustainability when selecting a location and assess the importance of each type of sustainability. These researchers randomly surveyed 3000 conference planners of various types and identified energy efficiency, recycling, and sustainable policies as the most important elements of a destination's sustainability. The study revealed that all sustainable policy factors scored above average, indicating their crucial position in destination selection decisions [2]. Furthermore They examined sustainability aspects such as the suitability of the application process, government support, social and political stability, regulatory requirements, government efficiency, and entry procedures [51,52]. However, these studies merely analyzed event participants' attitudes towards sustainability using ANOVA or IPA methods and did not examine the specific effects of policy sustainability. Later, Ajour et al. (2019) highlighted that positive policy factors from governments or managers are essential drivers of brand asset value when exploring the relationship between environmental, social, and management sustainability factors, and the intangible value of brand equity. The stronger an enterprise's economic, social, and management sustainability factors, the higher the overall value of the enterprise [53]. This means that consumers have a better impression of a brand's future development and are likely to pay a premium to support the brand's development when they perceive a brand's sustainable development measures to be supported by local government or policies. In conclusion, this study infers that sustainable event policies are an important influencing factor in improving brand image and increasing consumers' willingness to pay a premium. Therefore, this study proposes the following hypotheses: Hypothesis 4a. Policy sustainability practices significantly influence the brand image of event activities.
Hypothesis 4b. Policy sustainability practices significantly influence willingness to pay a price premium.

Impact of Brand Image and Willingness to Pay a Price Premium on Brand Loyalty
Brand image, willingness to pay a premium, and brand loyalty are important components of the brand asset model, and their relationship has been a topic of significant interest to scholars across various industries. In the tourism sector, Boo et al. (2009) conducted a study on tourists in Las Vegas and Atlantic City and validated the feasibility and effectiveness of a destination brand asset model comprising five dimensions: brand recognition, self-image, brand quality, brand value, and brand loyalty. The results showed inconsistent perceptions of destination brand value and loyalty among the two tourist groups, but the destination brand image had a consistent and strong relationship with destination loyalty [54]. Kim et al. (2018) investigated the festival industry and found that celebrity endorsement had no significant influence on festival brand recognition or loyalty, but festival brand image played a significant role in both festival brand loyalty and destination attachment [55]. Furthermore, in an investigation of the sports event industry, Chen et al. (2021) gathered 392 samples of marathon participants and employed various structural equation models to compare different path results, identifying the key factors that affect athletes' loyalty to the event city. The result showed that a positive destination image could directly enhance athletes' loyalty to the destination [56]. Nevertheless, while brand image has an essential role in constructing a destination brand asset model, it is not the only factor that contributes to the assessment of a destination's key dimensions, as pointed out by Konecnik and Gartner (2007) [57]. This conclusion was later verified by San Martin et al. (2019), who studied Spanish domestic and international tourists, constructed a destination brand asset model consisting of awareness-perceived image-perceived qualitysatisfaction-loyalty, and showed that perceived image indirectly and positively influenced loyalty in both samples [58]. Hence, a positive brand image can directly or indirectly enhance customers' loyalty to the brand. Based on the findings of previous studies, this research proposes the following hypothesis:

Hypothesis 5. Brand image significantly influences brand loyalty to event activities.
In today's competitive market, brand managers recognize that consumers' willingness to pay a higher price can lead to better profitability and sustainable competitive advantages for the company. Netemeyer et al. (2004) validated the brand asset model and found that the greater the consumers' willingness to pay a premium, the more likely it is to advance their purchasing behavior [31]. This highlights the importance of willingness to pay a premium in the brand asset model [28], as emphasized by Aaker (1996), as it directly relates to customer purchasing behavior and is considered a key factor in evaluating the overall performance of the brand asset model. Godey et al. (2016) examined the social media marketing activities of 845 luxury brand consumers and found that a positive brand image can enhance consumers' willingness to pay a higher price and their brand loyalty [59], which are important indicators of brand asset model performance. However, this study did not directly investigate the relationship between willingness to pay a higher price and brand loyalty behavior. Cassidy and Wymer (2016) empirically analyzed a loyalty model consisting of three items-belonging, trust, and importance-and found that loyalty has a significant positive relationship with willingness to pay a premium. However, it is worth noting that loyalty in this study refers to consumers' attachment to a specific service brand (attitude) rather than actual transaction behavior [60]. This suggests that while willingness to pay a premium is an important consideration for brand managers, research in the tourism industry exploring its direct relationship with customer loyalty is scarce, possibly due to customers' sensitivity to prices. Considering that previous studies have demonstrated that consumers are willing to pay more for brands they like [61], this study explores whether event participants' continuing participation is influenced by price factors and infers that willingness to pay a premium is an important influencing factor of customer loyalty behavior from the perspective of event attendees. Hence, the following hypothesis is proposed: Hypothesis 6. Willingness to pay a price premium significantly influences brand loyalty to event activities.

Questionnaire Design
To ensure the effectiveness of the questionnaire, we utilized established scales from both the domestic and international literature and modified them to align with our definitions and the Chinese context. After a review of the literature, the scales of sustainability (environmental, economic, social, and policy) were partly derived from ISO 26000  [63], and Cai and Si (2016) [12] for a total of 11 items. The brand equity measure was based on scales from Netemeyer et al. (2004) [31] and Kim et al. (2018) [55], for a total of 9 items. For the further development of the scales, modifications were made through 10 in-depth interviews with industry experts. To ensure a diverse range of both academic and practical perspectives, these interviewees included 3 academic experts, 2 government officials, 3 event organizers, and 2 event service providers, all related to the event industry. Each interview lasted at least half an hour and the in-depth interview process was documented. The researchers verified whether all 22 items collected during the literature review were applicable to the event industry in China. The aim of this process was to confirm that all selected sustainability practices could embody the concept of sustainable development in the event industry in China.
The results of the in-depth interviews indicated that all 22 initial items were appropriate for the Chinese context. On the other hand, over half of them suggested more detailed descriptions for items related to sustainability practices. According to these suggestions, the items' wordings were refined to describe the practices more clearly. For example, some experts pointed out that the questionnaire items should specify the sentence subject, so the item "the event present distinctive product" was revised to "the event that practice sustainable development concept have more distinctive products" to better reflect the subject. Similarly, some interviewees suggested that light pollution, air pollution, and noise pollution could all result from event activities and require different solutions; thus, the more specific the measures the organizers practice, the higher the degree of sustainability they can achieve. Therefore, the practice "taken measures to reduce pollution" was divided into "taken measures to reduce air pollution", "taken measures to protect air quality", and "taken measure to reduce noise pollution" to address various types of common pollution resulting from event activities. The practice of "improved relevant systems for events" was grouped into "has improved relevant systems for events" and "has given tax incentives" to emphasize the more favorable tax system in Hainan that was mentioned by 6 experts. In addition, the new practice of "help to spawn new business projects" was supplemented according to three interviewees' comments, because this practice is an efficient and significant indicator for evaluating economic sustainability. Finally, 17 items were generated to represent event sustainability and 9 items to represent brand equity. The questionnaire was conducted using a 5-point Likert scale, with 1 indicating strong disagreement and 5 indicating strong agreement.

Data Collection
Considering the need to select event activities with a certain scale and level of sustainability practices, this study selected participants from the China International Consumer Products Expo (Hainan Expo), one of the four national-level exhibitions in China, as research objects. The Hainan Expo advocates for sustainable consumption not only by holding high-level forums on sustainable consumption, but by also encouraging exhibitors to use environmentally friendly products for booth construction, showcasing new products with sustainable concepts, and actively promoting sustainability through multiple channels.
The first Hainan Expo was held in 2021. Since the first Hainan Expo, the organizers have been committed to the concept of low-carbon and sustainable development throughout, ensuring the event is green, pollution-free, and low-energy-consuming. Many brands participating in the Expo have also released initiatives related to sustainable consumption. For example, L'OREAL released a system known as product environmental and social impact labeling, which allows consumers to understand the environmental impact of products in an intuitive and comparable manner and provides comprehensive and transparent information. During the Expo, a sustainable consumption forum was also held. Thus, the Hainan Expo can be viewed as a representative sustainable event in China, making it highly relevant to the research topic.
The second Hainan Expo was held in the last week of July 2022. The data collection was conducted during the second Hainan Expo on-site by 4 trained undergraduate students.
All the respondents were selected according to the non-probability convenience sampling technique. To ensure that all the respondents had enough time to visit and understand the sustainability practices of this event, the survey was conducted during the last 4 days of the event. A total of 300 questionnaires were distributed. The outliers were removed, and 215 questionnaires were used for the final analysis.

Data Analysis and Results
The analysis within this study proceeded as follows: First, we used SPSS 22.0 to conduct a descriptive statistical analysis of the demographic data. Second, Smart PLS 3.0 was used to analyze the structural equation modeling (SEM), which was suitable for researchers to explore and test hypotheses based on mature theoretical foundations [64]. SEM can be used to analyze multiple dependent variables simultaneously. In addition, SEM allows researchers to calculate the overall fitness of different models to the same sample data to determine which model is closest to the relationship presented by the data. Therefore, SEM was an appropriate method to use in this study. Table 1 shows the results of the descriptive analysis, which include detailed sample profiles. The majority of respondents had received a junior college or bachelor's degree (76.3%), while 9.3% of respondents had a master's degree or above. In terms of age, 86.7% of the respondents were between 18 and 40 years old. Approximately half of the respondents were exhibitors, 26.5% were public visitors, and 15.3% of them were professional visitors. Over 85% of respondents had been aware of sustainability before attending the Expo, and approximately 90% of them had attended events that practiced sustainable behavior. Therefore, these results guarantee that participants had a certain awareness of sustainable practice behavior before they attended the Expo, further ensuring the quality of the sample.

Measurement Model
The model fit was tested based on the standardized root mean square residual (SRMR) value. SRMR is an absolute measure of model fit. The SRMR value of this study was 0.074, which is less than 0.08, indicating a good fit [65]. The measurement model of this study was evaluated through tests of reliability and validity. The factor loading value of all items ranged from 0.66 to 0.91, which was greater than 0.6. The value of Cronbach's α ranged from 0.69 to 0.87, which was higher than the value of 0.6 recommended by [66]. In addition, the C.R values were greater than 0.8 and the AVE values of all variables were higher than 0.5, which was suggested by [67]. These results confirmed the convergent validity and reliability of the measurement model ( Table 2). The discriminant validity of the measurement model was confirmed via the Fornell-Larcker criterion test and the heterotrait-monotrait ratio (HTMT) test. Table 3 presents the results of the Fornell-Larcker criterion test. All of the correlations with any other latent variables were smaller than their AVE root values [67]. Table 4 presents the result of the HTMT test. Discriminant validity has been proved since all of the HTMT values between the two reflective constructs were below 0.90 [68]. Thus, discriminant validity was demonstrated.  Table 5 presents the results of the hypotheses testing. First, the values of the inner and outer Variance Inflation Factor (VIF) were less than 2.02, which eliminated the multicollinearity issue among the variables. The results show that the four dimensions of economy, society, environment, and policy proposed in this paper can reflect the sustainable practice of exhibition activities. The ESPs have significant impacts on both BI (β = 0.30, p < 0.000) and WPP (β = 0.19, p < 0.05), and thus H1a and H1b are both supported. This indicates that the participants recognized the environmental sustainability behaviors implemented by the organizers during the exhibition, such as using reusable materials to build booths and disposing of waste in a harmless manner. They believed that these measures helped the Hainan Expo establish an image of sustainability. The ECSPs also have a significant effect on BI (β = 0.21, p < 0.000), but do not have a significant effect on WPP (β = 0.02); thus, H2a is supported while H2b is not supported. According to the results, the participants believe that the economic sustainability behaviors of the exhibition will promote the construction of a sustainable brand image for the Hainan Expo, but this does not mean that most exhibitors and visitors are willing to pay a price premium.

Hypothesis Testing
BI and (β = 0.28, p < 0.000) WPP (β = 0.32, p < 0.000) are significantly affected by the SSPs, while the PSPs have significant effects on both BI (β = 0.11, p < 0.01) and WPP (β= 0.14, p < 0.01). Therefore, H3a, H3b, H4a, and H4b are all supported. According to the results, the participants believe that the social and policy sustainability of the exhibition, such as promoting cultural integration, providing more leisure choices for local residents, standardizing the legal environment related to exhibitions, and improving related systems of exhibitions, can help the Hainan Expo to build a sustainable brand image.
In addition, the BI and WPP also have significant impacts on BL, with path coefficients reaching 0.38 (p < 0.000) and 0.45 (p < 0.000); thus, H5 and H6 are also supported. The results show that the brand image of sustainable development and the willingness to pay a premium help to enhance the brand loyalty of the participants, improving the overall competitiveness of the exhibition brand.
The results also indicate that the R2 values of the dependent constructs are 0.46 for BI and 0.25 for WPP, respectively. Meanwhile, 53% of the variance in the BL can be explained by BI and WPP. These findings indicate that the model has good explanatory power.

Conclusions
This study is grounded in the theory of sustainable development, aiming to investigate the impact of event sustainability on brand equity. A research framework was constructed to include sustainability in relation to events, brand image, willingness to pay a premium, and brand loyalty. The framework was then empirically tested, leading to the conclusions outlined below.
Sustainability in event activities, consisting of four dimensions (environment, economy, society, and policy), has a significant positive impact on brand image. In other words, practicing sustainability in events is an important way to enhance the brand image of events in view of sustainable development. The results show that all four dimensions have a positive impact on enhancing the brand image and also indicate that the environmental factors (β = 0.30) have the most direct effect, followed by social (β = 0.28), economic (β = 0.21), and policy (β = 0.11) factors. This conclusion is consistent with previous studies by authors such as Han [37,41,43,45,50,53].
Except for economic sustainability practices, all of the social, environmental, and policy dimensions have significant effects on participants' willingness to pay a premium. Among these dimensions, the social factor has the strongest direct effect (β = 0.32) on willingness to pay a premium, followed by the environmental (β = 0.19) and policy factors (β = 0.14). The results indicate that event participants, including exhibitors who purchase event booths and professional or general attendees, appreciate and are willing to pay a premium for sustainability implemented by event organizers. This finding is consistent with the results of Wang et al.'s (2022) study on consumers' willingness to pay a higher price for environmentally conscious products [44]. However, unlike previous research, this study found that although economic sustainability in events contributes to the construction of sustainable event branding, most attendees are not willing to pay a premium to participate in other events that embody sustainable development practices.
This study found that both brand image (β = 0.38) and willingness to pay a premium (β = 0.45) have a significant impact on brand loyalty among event participants. Specifically, event participants who perceive a positive brand image tend to exhibit increased loyalty toward the event brand. Furthermore, the degree of brand loyalty towards the event is positively correlated with the participants' willingness to pay a premium for the event.
These results are consistent with Boo's (2009) and Kim et al.'s (2018) studies, which identified a significant positive relationship between destination brand image and destination loyalty [54,55]. Additionally, the positive relationship between willingness to pay a premium and brand loyalty is consistent with the results of Godey et al.'s (2016) study on the beneficial effects of price premiums on brand loyalty [59].

Discussion
Based on these conclusions, it can be inferred that event organizers can enhance the image of events through the implementation of sustainable practices. Additionally, since events involve multiple stakeholders, it is important to establish a multidimensional sustainability assessment model to truly understand participants' perceptions of an event's brand image. This model should incorporate the attitudes of different types of participants and consider various dimensions of sustainability. This study shows that the environmental, social, economic, and policy dimensions of sustainability form an appropriate model for evaluating the sustainability of events. These dimensions complement one another and are not interchangeable.
Secondly, among the four dimensions, the economic dimension did not directly affect participants' willingness to pay premiums. This may be because the Hainan Expo is a large-scale event held at the Hainan Free Trade Port. Compared with events held in mainland China, the time and transportation costs are higher; moreover, nearly 77% of respondents were exhibitors (mostly from outside Hainan) and professional visitors (mostly from outside Hainan), who represent exhibiting companies aiming to reduce costs and increase profits. Economic dimension items focus on contributions to local economic development in Hainan rather than participating companies themselves, which does not resonate sufficiently with surveyors, thus providing no significant results. As other dimensions have shown significant results regarding willingness-to-pay-premiums behavior among participants in relation to sustainable activities during events, this result does not hinder their participation.
Furthermore, this study confirms that implementing sustainable practices in events not only enhances the image of the event brand but also encourages attendees and exhibitors to pay a premium for such events, resulting in greater loyalty towards the brand. These results suggest that both suppliers and consumers in the event industry recognize the importance of sustainable development, indicating a growing consensus on the need for sustainable practices in the industry. This is significant for the continued adoption and promotion of sustainable practices in the event industry. For instance, at the second Hainan Expo, the event organizers provided a pass/visitor card reuse service to reduce waste and encourage revisiting. The original pass/visitor card price was RMB 200, but this will be waived for attendees who reuse their pass cards at the third or fourth Hainan Expo. This process can be completed via the official app. This action achieved unexpected positive feedback from the participants. Exhibitors implemented this practice in favor of reducing re-attendance costs and mail delivery time, and this created a good impression of the event organizer because it shows that they are trying to reduce the negative impact of the event and protect the environment. Similarly, during the second Hainan Expo, all special cars (i.e., shuttle buses and special bus lines) associated with the event used clean energy and travel was free for participants. Participants indicated that this practice is very convenient and economical for them, especially during their first visit to the Hainan Expo and its host city.

Theoretical Implications
The conclusions drawn from this research offer valuable insights and contribute to the development and application of the theoretical understanding of sustainable practices in the events industry. This study developed and verified seventeen sustainability practices for events by carefully reviewing the relevant literature, interviewing experts, and verifying the findings based on a representative event in China. This was important because previous studies had limitations in terms of empirical research [10,12,16]. As few events practice sustainability in real-world scenarios, most of these studies merely provide a system of indicators without an empirical test, especially in the Chinese market in which sustainable events have only recently been introduced. In addition, this study identified one new factor (policy support) which is crucial and difficult to measure but significantly affects participants' perceptions and behavior [25,26]. Therefore, improving this dimension provides participants with a good impression and can trigger positive behavior. This finding provides new perspectives for event organizers and event host cities.
The current study extends the sustainability literature by utilizing event sustainability practices as constructs in the proposed theoretical model. Although some studies have mentioned and discussed the consequences of sustainability practices, they simply evaluated consumers' brand attitudes [4] and considered financial performance [47], or examined sustainability practices in the context of other fields, such as a green hotel [42,43], ecoagricultural applications [44], or the home appliance industry [45]. None of the previous research explored the impacts of sustainability practices systematically in the field of the event industry in relation to event brand equity to investigate their consequences via an empirical approach. Therefore, this study fills a research gap in the event literature by developing an appropriate approach to examine the linkage between the inputs of sustainable practices and the resulting event brand equity outputs. The findings of this empirical analysis confirmed the positive effects of implementing sustainable practices in events and provide a theoretical basis and practical evidence that sustainability practices can enhance event brand equity. Thus, the results offer solid research support to aid the event industry in achieving its sustainable development goals and bridging the gap between sustainable development theory and its practical application.
Consequently, the results are valuable as they address the contradiction between the investment in and the outcomes of sustainable practices in event management. According to this research, implementing sustainability practices not only enhances events' brand image but also does not deter attendees from participating, even with a premium price, but rather increases participants' loyalty toward the event brand.

Practical Implications
The results of our research indicated that incorporating sustainable practices into events can clearly benefit the event brands. Therefore, this study can be used as a basis for long-term development strategies for event organizers and corporations participating in said events. Currently, few events in China implement these practices due to concerns about costs. Unexpected environmental, social, and policy sustainability practices of the event under study showed positive effects on multiple participants' willingness to pay a price premium. These results provide support and guidance that may encourage event companies to consider incorporating sustainable practices into their events, especially for companies that still hesitate to adopt these practices. According to our results, event organizers should increase their investment in relevant measures and resources to promote sustainable development practices at their events. Environmental and social practices are the two important factors related to willingness to pay a price premium. Therefore, organizers could provide more concurrent events for exhibitors to practice social and environmental sustainability. For instance, event organizers of the Hainan Expo actively provide communication platforms for exhibitors and local institutions, and ultimately the Burberry and Hainan Re-form and Development Research Foundation jointly launched a three-year green ecological project in 2022. On the other hand, event organizers should endeavor to provide more convenient and value-added services for the price premium. For instance, the Hainan Expo adopts "no-touch" technology (e.g., face-scan) when participants enter the venue, provides "free shuttle buses", complimentary tickets for VIP participants invited by the exhibitors or organizers, and an electronic guidebook for participants. Furthermore, organizers can provide preferential accommodation prices for exhibitors by partnering with local hotel companies to reduce the costs of participation.
Another important implication of this study is its provision of a new approach to improve event brand image and brand loyalty. The results of hypothesis testing indicated that all sustainability practices had considerable effects on participants' brand image. Based on the results, event organizers should improve these practices, especially environmental practices which have the most significant effect, to improve brand image and brand loyalty efficiently. For instance, the organizers could provide a visitor card/pass reuse service to reuse materials; restrict the use of high-decibel speakers to reduce noise pollution; reduce the use of high-power consumption equipment, or switch to LED lighting to reduce the pollution caused by light sources; use low-volatility glues and paints and reusable materials to build booths; provide exhibitors with reusable handbags; use degradable tableware; and provide new energy shuttle buses. Additionally, organizers could provide an official service contractor to dispose of event waste or make agreements with event venues to ensure the waste generated during the event is disposed of in a suitable manner. Furthermore, the implementation of digital management systems can facilitate efficient and effective on-site event management. For example, the Hainan Expo provided smart power distribution to manage venue power and adopted a mini-program or APP for registration and reservation services.
This study proposed an appropriate group of practices that can be used by event organizers to ensure the sustainability of their events. The empirical results of the validity analysis confirmed the rationality of four dimensions for evaluating event sustainability in China. According to the results, event organizers need to balance environmental, social, economic, and policy aspects when implementing sustainability. This suggests that event organizers should consider the long-term impact when planning events and implementing relevant measures for sustainability. Not only should they adhere to the concepts of "green events" and "sustainable events" in material selection, energy consumption, and construction but they should also combine local economic development levels with relevant policies by supporting local communities through event hosting to achieve a positive relationship between event activities and host cities' development. In addition, event stakeholders (e.g., exhibitors, volunteers, governments, local citizens, event visitors, etc.) involved in event activities can use the research results to optimize their decision-making processes and innovate cooperation models. For instance, the results show that more than 85% of participants were already familiar with the concept of sustainability before attending the event; therefore, event organizers and exhibitors should pay more attention to related measures presented at events and create a sense of connection with visitors. More specifically, during planning or marketing processes, organizers can guide exhibitors to showcase their ideas for booth designs and encourage exhibitors or event volunteers to proactively introduce sustainable achievements to visitors. Event organizers should be encouraged to follow the example of the Hainan Expo and China International Import Expo by integrating the concept of sustainable development into the theme and preparation works of the event (i.e., introduce relevant sustainability concepts and initiatives in promotional materials; place a bulletin board in a conspicuous position in the exhibition hall; encourage exhibitors to create exhibits in their booths explaining how companies implement the concept of sustainability; promote sustainability measures during volunteer training and encourage them to introduce these concepts to visitors, etc.). Moreover, event organizers should publicize the positive social impacts of events (i.e., increase the leisure options of residents, enrich the types of products available to consumers, and endeavor to relieve traffic congestion) and determine ways to avoid negatively impacting citizens to earn the support of host cities' residents.
The results of the predictive validity analysis and path analysis also indicated that the strength of policy sustainability has a critical role in perfecting the sustainability practices of events and improving the participants' loyalty. Therefore, while promoting sustainable development in the event industry, the favorable support of government policies can greatly assist event companies in practicing and achieving sustainable development goals. The current results also demonstrated that creating a good legal environment, establishing excellent event-related systems, and providing certain tax incentives for event projects can indirectly promote active participation and brand promotion for event attendees, thereby driving the long-term sustainable development of the entire industry. Event organizers could seek government support for large-scale events that encourage attendees or citizens to use public transportation instead of driving, thus reducing greenhouse gas emissions. For instance, at the Hainan Expo, the local government coordinated two complimentary bus lines with 45 new energy buses for pass holders to encourage participants to use public transport, subsequently reducing energy consumption. Also, the host city's government provided a preferential amount of RMB 10,000 for the purchase of new energy vehicles. On the other hand, based on the "Hainan Province Carbon Peak Implementation Plan" released by the Hainan Provincial Government, the sale of fuel vehicles will be banned by 2030 and new energy vehicles will account for more than 45% of vehicles. Similarly, the Hainan province released an implementation plan to ban single-use plastic products and end the production, sale, and use of non-biodegradable plastic products in Hainan. These government measures provide clear guidance for environmental sustainability initiatives. Therefore, single-use plastic products and non-biodegradable plastic products cannot be used at events. Visitors and exhibitors are encouraged to use low-consumption and environmentally friendly equipment to reduce energy consumption as well. Furthermore, to attract new business projects to extend the after-event effects by encouraging exhibitors to set up local companies, the Hainan government announced corporate income tax (CIT) and individual income tax (IIT) preferential policies (i.e., a reduced 15% CIT rate and maximum 15% IIT rate). These policy practices will provide a guide for other event host cities to implement sustainability practices in event activities. In addition, governments must implement more specific criteria for sustainable events and evaluation systems to evaluate the degree of implementation. The government could structure a program to assess event sustainability management and provide a sustainable event label to guide and encourage the event industry.

Limitations and Future Research Directions
This study has some limitations that should be acknowledged. First, the sample consisted solely of participants from the Hainan Expo, which is one of the four major events organized by the government; thus, the generalizability of the results to other types of events or areas may be limited. It is suggested that various types of events should be included to obtain broader results. Future research should consider a wider range of events, including smaller-scale events, and expand the scope of the survey to capture a more complete picture of sustainable practices. Second, this study only focused on economic, social, environmental, and policy support, as the four dimensions of event sustainability. Increasing attention is being paid to sustainable development, and as the movement of sustainable events continues to grow, sustainable event attributes will need to be updated. Future research should consider the unique characteristics of event industry development in different regions and consider expanding the measurement dimensions to create a more comprehensive and diverse set of practical indicators. Finally, this study only considered the perception of brand equity from a consumer viewpoint when examining the output factors. Future research can take different perspectives of industry output into account, such as the perspective of financial-based outcomes of firms, to explore additional benefits of event sustainability.
Author Contributions: X.C., conceptualization, validation, data curation, investigation, resources, writing-original draft preparation, funding acquisition, supervision, and project administration; A.C., methodology, software, formal analysis, writing-original draft preparation, writing-review and editing, visualization, and funding acquisition. All authors have read and agreed to the published version of the manuscript.