Communicative Processes Underlying DIY eJuice Mixing Among Young Adult International ENDS Users.

The use of electronic nicotine delivery systems (ENDS) is increasing around the world, with contemporary trends outpacing scientific understanding of the health implications. Such trends include do-it-yourself eJuice mixing (DIY eJuice), which involves the unregulated homemade mixing of fogging agents, nicotine salts, and flavorants to create personalized liquid for ENDS products. The purpose of this study was to employ a grounded theory approach to gather formative data on the communicative processes surrounding the behavior of DIY eJuice mixing among international, young adult ENDS users. Participants were recruited locally for mini focus group discussions via SONA (n = 4) and internationally for an open-ended survey via Prolific (n = 138). Questions explored experiences with the online DIY eJuice community, motivations for mixing, information seeking strategies, flavor preferences, and perceived benefits of mixing. Thematic analysis and flow sketching revealed the underlying processes of social cognitive theory to explain the communicative processes of DIY eJuice mixing behaviors. Specifically, environmental determinants emerged in the form of online and social influences; personal determinants in the form of curiosity and control; and behavioral determinants following a benefits/barriers analysis, particularly regarding cost. These findings provide theoretical implications for the role of health communication constructs in understanding contemporary trends in ENDS use and practical implications for tobacco prevention messaging and tobacco control regulations.

Using the Theory of Planned Behavior to Anticipate DIY E-juice Mixing among Young Adult International E-cigarette Users.

Background: Trends in young adult use of electronic nicotine delivery systems (ENDS) and experimentation with do-it-yourself (DIY) e-juice mixing are growing around the world. Theoretical frameworks for examining secondary behaviors (i.e., mixing) embedded within a primary behavior (i.e., vaping) are limited, leading to challenges in scholarly understanding of behavioral performance. This study explored the theoretically driven factors surrounding ENDS users' decision to mix DIY e-juice through a multiple behavior test of the theory of planned behavior (TPB). Methods: An international sample of young adult participants aged 18-19 (n=203) was recruited from Prolific for an online crosssectional survey. Path modeling tested four theoretically driven models to explore behavioral performance of mixing. Findings: The data supported TPB expectations and revealed new paths for secondary behavior. Primary perceptions of attitudes, norms, and intention were predictive of the same secondary perceptions. In addition, for both primary and secondary behaviors, perceived norms were a function of perceived attitudes. For the secondary behavior, normative influence was experienced indirectly through perceived attitudes. Conclusion: DIY e-juice mixing is a product of perceived attitudes and behavioral control surrounding mixing as well as perceived attitudes, norms, and intention surrounding general ENDS use. While unregulated DIY experimentation increases among youth, these findings provide a lens for public health efforts seeking to reach and reduce use. Understanding DIY e-juice behaviors is essential to anticipate stockpiling behaviors and negative outcomes from amateur experimentation.

Policy-relevant differences between secondhand and thirdhand smoke: strengthening protections from involuntary exposure to tobacco smoke pollutants.

Starting in the 1970s, individuals, businesses and the public have increasingly benefited from policies prohibiting smoking indoors, saving thousands of lives and billions of dollars in healthcare expenditures. Smokefree policies to protect against secondhand smoke exposure, however, do not fully protect the public from the persistent and toxic chemical residues from tobacco smoke (also known as thirdhand smoke) that linger in indoor environments for years after smoking stops. Nor do these policies address the economic costs that individuals, businesses and the public bear in their attempts to remediate this toxic residue. We discuss policy-relevant differences between secondhand smoke and thirdhand smoke exposure: persistent pollutant reservoirs, pollutant transport, routes of exposure, the time gap between initial cause and effect, and remediation and disposal. We examine four policy considerations to better protect the public from involuntary exposure to tobacco smoke pollutants from all sources. We call for (a) redefining smokefree as free of tobacco smoke pollutants from secondhand and thirdhand smoke; (b) eliminating exemptions to comprehensive smoking bans; (c) identifying indoor environments with significant thirdhand smoke reservoirs; and (d) remediating thirdhand smoke. We use the case of California as an example of how secondhand smoke-protective laws may be strengthened to encompass thirdhand smoke protections. The health risks and economic costs of thirdhand smoke require that smokefree policies, environmental protections, real estate and rental disclosure policies, tenant protections, and consumer protection laws be strengthened to ensure that the public is fully protected from and informed about the risks of thirdhand smoke exposure.

Evaluation of a Social Media Campaign Designed to Increase Awareness of Thirdhand Smoke among California Adults.

Despite a growing body of research outlining the harms of thirdhand smoke (THS), the public remains generally unaware of risks and exposure routes. This project built on past tobacco prevention campaigns and the tenants of McGuire's input-output model to implement and evaluate a seven-month Facebook-disseminated campaign seeking to improve THS awareness among California adults (n = 1087). Multilinear regression showed that THS-related knowledge (χ2[6] = 19.31, p < .01), attitude (χ2[6] = 13.88, p < .05), and efficacy (χ2[6] = 13.81, p < .05) significantly increased by the campaign's end, with messages highlighting children's health (r = .110, p < .05), pets (r = .145, p < .01), and dust reservoirs (r = .144, p < .01) as the most persuasive. Path analysis modeling found campaign recall to be associated with changes in knowledge (ß = .161, p < .01), which predicated attitude change (ß = .614, p < .001) and, in turn, behavior change (ß = .149, p < .05). Findings suggest social media campaigns should continue to educate diverse populations about new tobacco risks and that tobacco control advocates should consider integrating educational THS messages.

Thirdhand Smoke Knowledge, Attitudes, and Behavior: Development of Reliable and Valid Self-report Measures.

INTRODUCTION: This study sought to provide essential tobacco control tools by testing the reliability and validity of new self-report scales developed to assess thirdhand smoke (THS) (ie, toxic tobacco residue) related knowledge, attitudes, and behavior (KAB). AIMS AND METHODS: Items for the KAB scales were adapted from established secondhand smoke (SHS) measures, reviewed to support face validity, and tested in a longitudinal online survey evaluating THS health messages. Participants were California adults at risk of THS exposure. For 7 months, the three KAB scales were completed monthly, and data from the first (n = 1086), third (n = 315), and seventh (n = 301) month surveys were used in these analyses. RESULTS: All three scales demonstrated consistent reliability and single-factor loading at all three timepoints for knowledge (αrange: .87-.90), attitude (αrange: .84-.87), and behavior (αrange: .80-.86). Similarly, analyses supported scale convergent validity (scale correlations rrange: .45-.85; all p values <.001), discriminant validity between smokers and nonsmokers (knowledge Cohen's drange: .57-.61, all p values <.001; attitude Cohen's drange: .78-.82, all p values <.001; behavior Cohen's drange: .90-.99, all p values <.001), and predictive validity (range R2KAB: .41-.48; all p values <.001). CONCLUSIONS: KAB scales about THS provide new opportunities for tobacco control advocates and scholars to identify gaps in knowledge, misperceptions, and obstacles to behavior change in order to guide the design of novel tobacco control policies and interventions. IMPLICATIONS: Numerous scales have been vetted as reliable and valid measures for assessing SHS-related KABs. Currently, standard measures of THS KABs are not available. This study tested three THS scales to fill this gap. The present findings provide tobacco control advocates, scholars, and practitioners tools for assessing KABs related to THS. This information is critical to development, implementation, and evaluation of novel tobacco control strategies.

We Post It, U Reddit: Exploring the Potential of Reddit for Health Interventions Targeting College Populations.

Reddit is an anonymous social media platform that allows users to create, modify, share, and discuss content. While this platform is widely used by mainstream audiences, little research exists on how Redditors respond to health information when it appears in general, non-health specific forums called subreddits. Guided by media system dependency theory, the purpose of this study was to anonymously intervene on college subreddits to explore how Redditors interacted with messages about smoke-free policy compliance. Two messages were posted two weeks apart on ten college subreddits, yielding 370 comments (per thread range = 66-0) and 552 Karma points (per thread range = 123-0). A content analytic approach was employed, identifying eight content themes, and classifying message tone. The most popular themes were general smoking [n = 85], animosity toward smoke-free policies/compliance [n = 68], and smoke-free policy/compliance support [n = 65]). Most comments expressed a neutral tone [n = 196]. Data suggest that Redditors are willing to interact with health content on their college subreddits to varying degrees, especially if this content conforms to norms of the subreddit and/or platform. Implications from the findings suggest important considerations for use of Reddit as a future site for health interventions.

Remediating Thirdhand Smoke Pollution in Multiunit Housing: Temporary Reductions and the Challenges of Persistent Reservoirs.

INTRODUCTION: Toxic tobacco smoke residue, also known as thirdhand smoke (THS), can persist in indoor environments long after tobacco has been smoked. This study examined the effects of different cleaning methods on nicotine in dust and on surfaces. AIMS AND METHODS: Participants had strict indoor home smoking bans and were randomly assigned to: dry/damp cleaning followed by wet cleaning 1 month later (N = 10), wet cleaning followed by dry/damp cleaning (N = 10) 1 month later, and dry/damp and wet cleaning applied the same day (N = 28). Nicotine on surfaces and in dust served as markers of THS and were measured before, immediately after, and 3 months after the cleaning, using liquid chromatography with triple quadrupole mass spectrometry (LC-MS/MS). RESULTS: Over a 4-month period prior to cleaning, surface nicotine levels remained unchanged (GeoMean change: -11% to +8%; repeated measures r = .94; p < .001). Used separately, dry/damp and wet cleaning methods showed limited benefits. When applied in combination, however, we observed significantly reduced nicotine on surfaces and in dust. Compared with baseline, GeoMean surface nicotine was 43% lower immediately after (z = -3.73, p < .001) and 53% lower 3 months later (z = -3.96, p < .001). GeoMean dust nicotine loading declined by 60% immediately after (z = -3.55, p < .001) and then increased 3 months later to precleaning levels (z = -1.18, p = .237). CONCLUSIONS: Cleaning interventions reduced but did not permanently remove nicotine in dust and on surfaces. Cleaning efforts for THS need to address persistent pollutant reservoirs and replenishment of reservoirs from new tobacco smoke intrusion. THS contamination in low-income homes may contribute to health disparities, particularly in children. IMPLICATIONS: Administered sequentially or simultaneously, the tested cleaning protocols reduced nicotine on surfaces by ~50% immediately after and 3 months after the cleaning. Nicotine dust loading was reduced by ~60% immediately after cleaning, but it then rebounded to precleaning levels 3 months later. Cleaning protocols were unable to completely remove THS, and pollutants in dust were replenished from remaining pollutant reservoirs or new secondhand smoke intrusion. To achieve better outcomes, cleaning protocols should be systematically repeated to remove newly accumulated pollutants. New secondhand smoke intrusions need to be prevented, and remaining THS reservoirs should be identified, cleaned, or removed to prevent pollutants from these reservoirs to accumulate in dust and on surfaces.

Persistent tobacco smoke residue in multiunit housing: Legacy of permissive indoor smoking policies and challenges in the implementation of smoking bans.

Secondhand smoke (SHS) is a common indoor pollutant in multiunit housing (MUH). It is also the precursor of thirdhand smoke (THS), the toxic mixture of tobacco smoke residue that accumulates in indoor environments where tobacco has been used. This study examined the levels, distribution, and factors associated with THS pollution in low-income MUH. Interviews were conducted 2016-2018 in a cross-sectional study of N = 220 MUH homes in San Diego, California. Two surface wipe samples were collected per home and analyzed for nicotine, a THS marker, using liquid chromatography-triple quadrupole mass spectrometry. Nicotine was detected in all homes of nonsmokers with indoor smoking bans (Geo Mean = 1.67 µg/m2; 95% CI = [1.23;2.30]) and smokers regardless of an indoor ban (Geo Mean = 4.80 µg/m2; 95% CI = [1.89;12.19]). Approximately 10% of nonsmokers' homes with smoking bans showed nicotine levels higher than the average level in homes of smokers without smoking bans from previous studies (≥30 µg/m2). Housing for seniors, smoking bans on balconies, indoor tobacco use, difficult to reach surfaces, and self-reported African-American race/ethnicity were independently associated with higher THS levels. Individual cases demonstrated that high levels of surface nicotine may persist in nonsmoker homes for years after tobacco use even in the presence of indoor smoking bans. To achieve MUH free of tobacco smoke pollutants, attention must be given to identifying and remediating highly polluted units and to implementing smoking policies that prevent new accumulation of THS. As THS is a form of toxic tobacco product waste, responsibility for preventing and mitigating harmful impacts should include manufacturers, suppliers, and retailers.

#Selfharm on #Instagram: Examining User Awareness and Use of Instagram's Self-harm Reporting Tool.

Self-harm-related posts on social media are a growing public health concern. To address the high rate of self-harm posts on their platform, Instagram introduced (in 2016) a tool for users to anonymously report posts that suggest engagement in, or support for, self-harm. Grounded in diffusion of innovation and the theory of planned behavior, the purpose of this study was to evaluate awareness of, and intention to use, the self-harm reporting tool among Instagram users. Survey data collected from 417 undergraduate Instagram users suggests that users are generally unaware that the self-harm reporting feature exists within the platform. However, once informed that the tool is available, regression analysis found attitudes, subjective norms, and perceived behavioral control to predict high intention to use the tool as a method for addressing risks of self-harm. Implications from these findings extend theoretical understandings of social media-based health behavior as well as practical recommendations for reducing risks of self-harm on social media platforms.

I Sought It, I Reddit: Examining Health Information Engagement Behaviors among Reddit Users.

Given the wide use of social media, these platforms have become important channels for understanding health-related information engagement processes. Reddit is a social media platform dedicated to user-generated content and discourse around the world. However, little research exists regarding use of the platform. Guided by the diffusion of innovation theory, the purpose of this study was to analyze Reddit users' behaviors on the platform related to perceptions of information credibility, health information seeking, and behavioral enactment of information found. Data were collected via survey from Reddit users around the world (n = 389). Data suggest that although Reddit use and perceived information credibility are unrelated to acting on the information found on Reddit, users who are specifically seeking health-related information are more likely to enact the information in their lives. Implications from the findings suggest important considerations for communication scholars, media advocates, and health promotion practitioners.

Social Media Campaign Effects: Moderating Role of Social Capital in an Anti-Smoking Campaign.

This study examined the effects of an anti-smoking campaign that employs a crowdsourcing method with a social networking service. Drawing upon social capital scholarship and the expression effect research paradigm in eHealth systems, the study also investigated the roles of social trust and community life satisfaction in the social media campaign that has a specific geographical boundary. To that end, we conducted an experiment using a two-group pretest-posttest design. We randomly assigned 201 participants to two conditions: "campaign message reception only" as a control group and "message reception and expression" as a treatment group in which participants fully engaged in the campaign process by sharing their own campaign ideas with other participants. Findings revealed that social trust and community life satisfaction interacted with the treatment condition to positively affect persuasive intentions, but in distinct ways. Social trust moderated the effect of the message reception and interaction condition on participants' willingness to encourage community members to stop smoking. In contrast, community life satisfaction moderated the effect of the treatment condition on encouraging others to comply with the community's anti-smoking policy. These results provide theoretical and practical implications related to the roles of social capital in geographically defined social media campaigns.

Using the Theory of Planned Behavior to Guide Focus Group Development of Messages Aimed at Increasing Compliance With a Tobacco-Free Policy.

PURPOSE: This study details the persuasive message development for a theory-based campaign designed to increase compliance with a university's tobacco-free policy. APPROACH: The theory of planned behavior (TPB) guided message design and evaluation for focus group-tested messages that were adapted to the context of complying with a tobacco-free policy. SETTING: The study was conducted at a university located in the tobacco belt. PARTICIPANTS: Undergraduate focus group participants (n = 65) were mostly male (69%), white (82%), and freshman (62%) who smoked at least 1 cigarette in the last 30 days; on-campus smoking percentages were never/rare (60%), occasionally (23%), and often/frequently (16%). METHOD: Data analysis used a theoretical thematic approach to identify how the TPB constructs related to perceptions of message effectiveness. RESULTS: Participants responded favorably to attitudinal strategies about health, respect, and university figures; they rejected approaches they considered juvenile and offensive. They also discussed the impact of noncompliance and avoiding overgeneralized statements for addressing subjective norms, suggesting shortening text, adjusting picture location, and emphasizing the importance of compliance to increase perceptions of behavioral control. CONCLUSION: Applying theory to preexisting messages is challenging. The design approach in this study is an evidence-based strategy that can be used as a universal process for message adaptation. Results offer health promotion suggestions for designing messages aimed at improving undergraduate smokers' willingness to comply with tobacco-free campus policies.

Tobacco-Free Policy Compliance Behaviors among College Students: A Theory of Planned Behavior Perspective.

The purpose of this study was to examine the theory of planned behavior (TPB) as a framework for understanding tobacco-free policy compliance behaviors. Undergraduate student smokers (n = 479) on a college campus with a tobacco-free policy were randomly selected to report their tobacco-free compliance behaviors and respond to TPB items. A path analysis found all constructs of the TPB model to be significantly related to tobacco-free policy compliance behaviors. The results obtained from this study fill gaps in the mostly atheoretical literature regarding our understanding of tobacco-free policy compliance behaviors as well as extend our knowledge of the TPB. Implications for this study provide recommendations for universities, health organizations, and government agencies currently attempting to enforce compliance with a tobacco-free policy.

Rural Print Media and a Tailored Advocacy Intervention for Smoke-Free Policy.

PURPOSE: To examine frequency, prominence, and content of local print media after a 4-year policy advocacy intervention. DESIGN: This was a controlled community-based trial. SETTING: The study took place in 39 rural counties (22 intervention, 17 comparison). SUBJECTS: Subjects consisted of 2525 newspaper articles monitored over 18 quarters (July 2007 to December 2011). INTERVENTION: One key element of the tailored policy advocacy intervention delivered by community advisors was building demand for smoke-free policy via media advocacy strategies. MEASURES: Media clips were coded to assess number of articles; percent of tobacco-related articles on the front page or bold heading section; percent of pro-health articles; and percent of articles with secondhand smoke (SHS)-relevant topics or themes. ANALYSIS: Coded data were entered into Atlas.ti software. Article frequencies and attributes were compared between groups and over time using negative binomial regression for longitudinal data, with county-level demographics as covariates. RESULTS: In the last 3 years, there were approximately twice as many articles in intervention than in comparison counties. Media clips from newspapers in intervention counties were between 1.4 and 2 times more likely to have front page placement and percent of relevant topic or theme than were those in comparison counties. There was no difference in rate of pro-health articles by group. CONCLUSION: The policy advocacy intervention to promote smoke-free policy increased media attention to SHS and may have increased public awareness of issues related to smoke-free policy.

Lay Epistemology of Breast Cancer Screening Guidelines Among Appalachian Women.

Recent changes to the U.S. Preventive Services Task Force guidelines for breast cancer screening have contributed to increased patient uncertainty regarding the timing and appropriateness of screening behaviors. To gain insight into the lay epistemology of women regarding breast cancer screening practices, we conducted in-depth, face-to-face interviews with 24 adult women living in a medically underserved Appalachian region. We found that women were unaware of breast cancer screening guidelines (i.e., start age, frequency, stop age). Qualitative analysis revealed two lay epistemological narratives establishing (a) uncertain knowledge and ambiguity about breast cancer screening guidelines but certain knowledge of other women's experiences with breast cancer diagnoses, and (b) feelings of knowing one's own body best and seeing the value in "overscreening" to save even one life. Our findings have theoretical and practical implications for scholars and practitioners seeking to improve knowledge or behavior regarding adherence to breast cancer screening recommendations.

Communication, Reasoning, and Planned Behaviors: Unveiling the Effect of Interactive Communication in an Anti-Smoking Social Media Campaign.

This study examines direct and indirect effects of interactive communication in an antismoking social media campaign. To that end, we pose a multitheoretical framework that integrates communication mediation models and the Theory of Planned Behavior. To test the theorized model, we conducted an experiment using a two-group pretest-posttest design. Participants (N = 201) were randomly assigned into two experimental conditions: "campaign message reception only" as a control group and "message reception and social interaction" as a treatment group, in which the participants contributed to the antismoking campaign by posting their own campaign ideas and information they found through mediated and interpersonal communication. The findings show that interactive communication catalyzes the participants' information searching behaviors through diverse communication channels. In turn, increased media use plays a crucial role in changing their attitudes and perceived social norms about smoking behaviors, and eventually reducing smoking intention. This study affirms that the theory of planned behavior is effective in predicting behavioral intention and demonstrates the usefulness of a multitheoretical approach in interactive campaign research on social media.

Using communication to manage uncertainty about cervical cancer screening guideline adherence among Appalachian women.

Changes to the United States Preventive Services Task Force (USPSTF) recommendations for cervical cancer preventive services have led to patient confusion, especially in medically underserved populations. We investigated how patient uncertainty concerning cervical cancer screening guidelines is appraised and managed through communication with healthcare providers by conducting in-depth, face-to-face interviews with 24 adult women between the ages of 24 and 65 (m = 41, SD = 14) living in Appalachia Kentucky. In general, participants expressed a high degree of uncertainty about the updated cervical cancer screening guidelines and appraised this uncertainty as both a danger and an opportunity. Communication with healthcare providers served both to exacerbate and to mitigate patient uncertainty. The study identifies how health care providers may use the change in USPSTF guidelines as a 'teachable moment' to productively counsel patients on the importance of timely screening, the typical progression of certain types of high-risk HPV infection to cervical cancer, and the importance of follow-up care.

Navigating the thin-ideal in an athletic world: influence of coach communication on female athletes' body image and health choices.

This study sought to investigate how interpersonal communication between coaches and female athletes influences the female athletes' perceptions of body image and health choices. Much of the current literature has focused on the fact that female athletes are at risk for disordered eating and a distorted body image due to susceptibility to the feminine "thin-ideal" while maintaining the fitness levels necessary to compete in their sport. However, very little research has examined how interpersonal interaction plays a role in female athletes' body image perceptions and health behaviors. Utilizing the Communication Theory of Identity (CTI) as a lens to examine communication between female athletes and their coaches, the researchers analyzed transcripts from in-depth interviews with 28 female athletes and identified themes within the personal, relational, enacted, and communal layers of identity. Coach communication with their female athletes was found to be influential to the athletes' body images and health choices.

Creating Effective Media Messaging for Rural Smoke-free Policy.

OBJECTIVES: Objectives were to (1) explore perceived effectiveness of existing smoke-free print advertisements in rural communities and (2) generate message content, characteristics, and media delivery channels that resonate with residents. DESIGN AND SAMPLE: Qualitative methods design. Thirty-nine rural adults recruited by community partners. MEASURES: Content analysis of findings from individuals in four focus groups who participated in general discussion and reviewed eight print ads related to secondhand smoke (SHS) and smoke-free policy. RESULTS: Six content themes were identified: smoking/SHS dangers, worker health, analogies, economic impact, rights, and nostalgia. Seven message characteristics were recognized: short/to the point, large enough to read, graphic images, poignant stories, statistics/charts/graphs, message sender, and messages targeting different groups. Four media delivery channels were considered most effective: local media, technology, billboard messages, and print materials. CONCLUSIONS: Seeking input from key informants is essential to reaching rural residents. Use of analogies in media messaging is a distinct contribution to the literature on effective smoke-free campaigns. Other findings support previous studies of effective messaging and delivery channels. Further research is needed to examine effectiveness of themes related to message content in smoke-free ads and delivery strategies. Effective media messaging can lead to policy change in rural communities to reduce exposure to SHS.

Outdoor tobacco smoke exposure at the perimeter of a tobacco-free university.

There are few studies measuring exposure to outdoor tobacco smoke (OTS). Tobacco users often gather at the boundaries of tobacco-free campuses, resulting in unintended consequences. The objective of this study was to measure exposure levels from OTS on sidewalks bordering a tobacco-free university campus. Data were collected while walking along a sidewalk adjacent to a medium traffic road between May and August 2011. Monitoring occurred during "background," "stop," and "walk-through" conditions at and near hot spot area to measure fine particulate matter (< 2.5 microm; PM2.5) from OTS using a portable aerosol monitor The average PM2.5 levels during stop and walk-through conditions were significantly higher than during background conditions. PM2.5 peak occurrence rate and magnitude of peak concentration were significantly different depending on smoking occurrence. The peak occurrence rate during the stop condition was 10.4 times higher than during the background condition, and 3.1 times higher than during the walk-through condition. Average peak PM2.5 concentrations during the stop condition were 48.7% higher than during the background condition. In conclusion, individuals could be exposed to high levels of PM2.5 when stopping or even passing by smokers outdoors at the perimeter of tobacco-free campuses. The design and implementation of tobacco-free campus policies need to take into account the unintended consequences of OTS exposure at the boundaries. Implications: In this study, outdoor tobacco smoke (OTS) exposure was measured at the perimeter of tobacco-free campus. OTS exposure could be determined by peak analysis. Peak occurrence rate and peak concentration for OTS exposure were identified by using peak analysis. People could be exposed to high levels of PM2.5 when standing or even passing by smokers at the perimeter of tobacco-free campus. OTS exposure measurement in other outdoor locations with smokers is needed to support outdoor smoking regulation.