Skin Barrier and Calcium

( Sang Eun Lee ),( Seung Hun Lee ) 대한피부과학회 2018 Annals of Dermatology Vol.30 No.3

Epidermal barrier formation and the maintenance of barrier homeostasis are essential to protect us from the external environments and organisms. Moreover, impaired keratinocytes differentiation and dysfunctional skin barrier can be the primary causes or aggravating factors for many inflammatory skin diseases including atopic dermatitis and psoriasis. Therefore, understanding the regulation mechanisms of keratinocytes differentiation and skin barrier homeostasis is important to understand many skin diseases and establish an effective treatment strategy. Calcium ions (Ca²⁺) and their concentration gradient in the epidermis are essential in regulating many skin functions, including keratinocyte differentiation, skin barrier formation, and permeability barrier homeostasis. Recent studies have suggested that the intracellular Ca²⁺ stores such as the endoplasmic reticulum (ER) are the major components that form the epidermal calcium gradient and the ER calcium homeostasis is crucial for regulating keratinocytes differentiation, intercellular junction formation, antimicrobial barrier, and permeability barrier homeostasis. Thus, both Ca²⁺ release from intracellular stores, such as the ER and Ca²⁺ influx mechanisms are important in skin barrier. In addition, growing evidences identified the functional existence and the role of many types of calcium channels which mediate calcium flux in keratinocytes. In this review, the origin of epidermal calcium gradient and their role in the formation and regulation of skin barrier are focused. We also focus on the role of ER calcium homeostasis in skin barrier. Furthermore, the distribution and role of epidermal calcium channels, including transient receptor potential channels, store-operated calcium entry channel Orai1, and voltage-gated calcium channels in skin barrier are discussed. (Ann Dermatol 30(3) 265∼275, 2018)

차세대 Barrier 물질 개발 동향

안희성,이종석 한국막학회 2015 멤브레인 Vol.25 No.2

고분자의 용이한 가공성과 우수한 투명성, 그리고 합리적인 비용 효율로 인해 식품 포장 산업에서 금속이나 유리용기들을 고분자 기반의 포장 소재들로 대체하려는 경향이 전 세계적으로 널리 퍼지고 있다. Barrier 고분자들은 산소, 이산화탄소, 수증기 등 대기 가스에 대한 낮은 투과성을 나타내고 있어 식품 포장 산업 이용에 유용하다. 이러한 식품 포장 산업의 전반적인 추세와 함께, 산소에 민감한 주스, 착향 음료, 그리고 에너지 음료 등 새로운 식품 산업의 성장으로 인해 고성능의 barrier 특성, 특히 O2와 CO2에 대해 낮은 투과성을 지닌 고분자 포장 소재의 개발이 시급한 상황이다. 기존의 고분자에 기반한 barrier의 성능 향상은 새로운 식품 포장 산업에 급격한 변화를 줄 것이다. 본 총설에서는 (1) antiplasticization을 유도한 barrier 소재들, (2) antiplasticization과 crystallization을 사용한 barrier 성능 상승 효과, (3) 새로운 barrier 고분자들, (4) 나노합성 소재, (5) 혼합 고분자 등과 더불어, 차세대 포장 소재들의 특성 분석을 소개하고자 한다. A global trend of replacing metal or glass containers with polymer-based packaging materials has been prevalent in the food packaging industry due to their ease in processibility, excellent transparency, and good cost efficiency. Barrier polymers tend to show low permeabilities for atmospheric gases such as oxygen, carbon dioxide, and water vapor, which allow them to be utilized in the food and beverage packaging industry. With the current global trend, expansion of polymeric packaging materials to new markets such as oxygen sensitive juices, flavored water, and energy drinks requires improved CO2 and O2 barrier properties. The improvement of the existing polymer-based barrier platform will enable a rapid market impact. In this paper, the current barrier technologies such as (1) antiplasticization-induced barrier materials, (2) synergistic effect of antiplasticization and crystallization, (3) new barrier polymers, (4) nanocomposite materials, and (5) polymer blending are introduced with their characterization techniques for the development of advanced packaging materials

다문화가정 청소년의 진로장벽인식에 따른 잠재집단분류 및 계층별 영향요인과 집단별 진로결정성 차이

곽은정,이수경 한국국제문화교류학회 2022 문화교류와 다문화교육 Vol.11 No.6

This study classified groups according to career barrier perception, explored factors affecting each group, and examined differences in career determination according to each categorized group to reduce career barriers and enhance career decisions that serve as obstacles in the career decision-making process of multicultural adolescents. For this study, the eighth dataset of the Multicultural Adolescent Panel Survey of the National Youth Policy Institute was used. Latent profile analysis was performed to classify latent groups for career barrier perception, and a multinomial logistic regression analysis was conducted to explore influencing factors based on the latent group. A cross-analysis was conducted to identify the differences in career determination according to the latent group. Major findings were as follows: first, the latent group for career barrier perception was divided into four groups: lowest- to low-career barrier perception group, middle-career barrier perception group, high-career barrier perception group, and highest-career barrier perception group. Second, among the factors affecting the career barrier perception groups, self-esteem and achievement motivation were found to lower career barrier perception, while high school type and the mother’s country of origin and career-related behavior were deeply affected. The accepting attitude of Korean culture, which is a sub-factor of bicultural acceptance, was partially meaningful, but foreign culture acceptance attitude, gender, and household income did not affect career barriers. Third and last, for career determination after high school for the latent group, the lower the level of awareness of career barriers, the lower the level of career indecision, and the highest percentage of all groups chose to attend domestic universities. Therefore, this study suggested ways to recognize the importance of psychological factors and actively utilize bicultural factors to lower career barriers for multicultural adolescents and enhance adaptive career development and decisions. 본 연구는 다문화가정 청소년의 진로장벽을 낮추고 진로결정성을 높이기 위해 진로장벽인식에 따른 잠재집단을 분류하여 각 집단에 영향을 미치는 요인을 탐색하고, 분류된 집단에 따른 진로결정성의 차이를 알아보았다. 본 연구를 위해서 한국청소년정책연구원에서 실시한 다문화청소년 패널 조사 8차 자료를 활용하였다. 진로장벽인식 잠재집단 분류를 위해 잠재프로파일 분석을 실시하였고, 잠재집단에 따른 영향 요인 탐색을 위해 다항로지스틱 회귀 분석을 실시하였다. 마지막으로 잠재집단에 따른 진로결정성의 차이를 알아보기 위해 교차분석을 실시하였다. 본 연구 결과 첫째, 진로장벽인식 잠재집단은 4개의 집단으로 분류되었다. 둘째, 진로장벽인식 집단에 영향을 미치는요인 가운데 자아존중감, 성취동기는 진로장벽인식을 낮추는 요인으로, 모의 출신국, 고등학교 유형, 모의 진로관련 행동은 부분적으로 영향을 미치는 것으로 나타났다. 이중문화수용태도의 하위요인 가운데 한국문화수용태도는 부분적으로 유의했으나, 외국문화수용태도, 성별, 가구소득은 진로장벽에 영향을 주지 않는 것으로 확인되었다. 셋째, 잠재집단에 따른 고등학교 이후 진로결정성은 진로장벽 인식 수준이 낮은 집단일수록 진로미결정 수준이 낮았으며, 모든 집단에서 국내대학진학으로 결정한 비율이 가장 높았다. 따라서 다문화가정 청소년의 진로장벽을 낮추고 적응적인 진로발달과 진로결정성을 높이기 위한 방안으로, 심리·행동적 요인 및 이중문화 요인을 적극적으로 활용할 수 있는 방안들을 제시하였다. 본 연구는 다문화 가정 청소년의 진로에 관한 추후연구에 학문적 도움을 줄 수 있을 것이며, 진로장벽을 감소시킬 수 있는 교육적·상담적방안을 마련하는데 기여할 수 있을 것이라 기대한다.

Analysis of Influence Factors on AC Breakdown Characteristics of Rod-Barrier Gap and Electric Field Simulation

Hu Kai,Li Guochang,Gu Zhenlu,Zhang Fan,Wei Yanhui,Lei Qingquan 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3

The insulation performance of air gap can be improved by inserting insulation barriers into the high voltage box with limited space. The influence of the barrier dimension, barrier thickness, barrier position and surface state of epoxy resin barrier on the AC breakdown characteristics of the “rod electrode-insulation barrier-ground electrode” system are discussed in the work. An equal-size model of the insulation system is established to analyze the influence of the insulation barrier on electric field and the discharge mechanism. The experimental results indicate that the breakdown voltage is improved significantly by enlarging the barrier dimension, up to twice as much. In contrast, the barrier thickness has little effect on the breakdown voltage because the discharge is mainly along the barrier surface. Besides, the breakdown voltage can be increased by reducing the distance between insulation barrier and rod electrode, this is because of the blocking effect of insulation barrier on the corona layer around the electrode, which can hinder the development of charges to the ground electrode, thus delaying the discharge process. The breakdown voltage increases with the barrier surface roughness because of the prolongation of discharge path and the distortion of local electric field. The breakdown voltage decreases with the rise of temperature, it decreases to 37.5 kV when temperature rose to 60 °C. Due to the increase of free charges mobility, the corresponding surface resistivity decreases from 16.2 × 1014 Ω at 20 °C to 3.14 × 1014 Ω at 60 °C. This work can provide support for the reasonable design of insulation barriers in engineering application.

배리어프리(Barrier-Free) 영화 활성화 방안

최영환(Choi, Youngwhan),신주연(Shin, Juyeon),염은유(Yeom, Eunryu),오강국(Oh, Ganggook),오세은(Oh, Seeun),윤혜정(Youn, Hyejeong),정현지(Jeong, Hyunjee),최윤경(Choi, Younkyoung),한지나(Han, Jina),홍소망(Hong, Somang),조성희(Cho, Sunghu 한국상담복지경영학회 2019 상담복지경영연구 Vol.- No.3

본 연구는 장애인의 삶의 질과 밀접한 관련성을 가진 문화향유권을 증진하기 위한 방안을 살펴보기 위한 목적으로 수행되었다. 특히 다양한 문화활동 중 장애인들이 가장 많이 이용하고 있는 활동인 영화 관람에 초점을 맞추었다. 이를 위하여 국내외 배리어프리 영화의 실태와 제도를 살펴보았다. 또한 배리어프리 영화 상영 경험에 따른 배리어프리 영화에 대한 수용도와 장애인에 대한 인식 변화를 검증하였다. 추가적으로 관련 전문가들을 대상으로 인터뷰를 통해 배리어프리 영화의 실태와 활성화 방안을 모색하였다. 연구결과를 살펴보면, 국내의 배리어프리 영화는 2010년대 이후 발전해 오고 있으나, 여전히 장애인들의 문화 활동에 대한 욕구를 충족시키기에는 미흡한 수준이다. 특히 배리어프리 영화의 절대적인 양적 측면의 성장이 미흡한 상황이므로 이에 대한 대책이 필요하다. 국내 배리어프리 영화의 확대를 위한 방안 모색에 있어서 영국은 좋은 사례가 될 수 있으므로 이에 대한 추가적인 검토가 필요하다. 배리어프리 영화 경험에 따른 배리어프리 영화에 대한 수용도와 장애인에 대한 인식 변화를 살펴본 결과에서는 배리어프리 영화를 경험한 경우 배리어프리 영화에 대한 수용도가 증가하고, 장애인에 대한 인식 역시 개선되는 것으로 나타났다. 이러한 결과를 기반으로 하여 배리어프리 영화 경험 증대를 위한 기회 확대, 기업차원이 활성화 방안 추진, 제도의 개선을 제시하였다. The purpose of this study was to find measures to promote cultural rights that are closely related to the quality of life of people with disabilities. In particular, the focus was on movies, which are the most used films for people with disabilities in various cultural activities. We examined the actual conditions and systems of barrier-free films at home and abroad. Also, according to the barrier-free movie screening experience, we examined the change of acceptance of barrier-free movie and perception of disabled people. Additionally, interviews were conducted with relevant experts to find out the status of barrier-free films and how to activate them. Result shows that barrier-free films in Korea have evolved since the 2010s, but are still insufficient to meet the needs of disabled people for their cultural activities. In particular, since the absolute quantitative growth of barrier-free movies is not enough, measures need to be taken. The UK can be a good example of exploring ways to expand domestic barrier-free films, and additional consideration is needed. As a result of examining barrier-free film acceptance and recognition of disabled people according to barrier-free film experience, the barrier-free film experience showed that acceptance of barrier-free film increased and recognition of disabled people also improved. On the basis of results, this study suggested the expansion of opportunities to increase the barrier-free movie experience, the promotion of corporate-level activation, and the improvement of the system.

장기적 관점에서 전환장벽은 긍정적인가? -전환장벽에 대한 심리적 반발을 중심으로-

정윤희 한국마케팅관리학회 2013 마케팅관리연구 Vol.18 No.1

This study attempts to explain the negative effect of switching barrier in the setting of service. To suggest the negative effect of switching barrier, we established the outline of model, based on psychological reactance theory, and then adjusted the specific constructs which are included in the model, based on the attributes of switching context. The negative effects model of switching barriers which we present in this study includes the antecedents and consequences of psychological reactance to the switching barrier. The former factors consist of switching barrier traits and personal traits. The latter factors consist of commitment to the present provider, negotiation intent to the switching barrier, and expectation to the alternative provider. Through reviewing previous studies, we suggested external(service provider) attribution and justification of switching barrier as switching barrier traits, and reactance tendency, variety seeking as personal traits. Also, we expect that these switching barrier traits and personal Traits effect psychological reactance to the switching barrier, in turn psychological reactance to the switching barrier effect commitment to the present provider, negotiation intent to the switching barrier, and expectation to the alternative provider. Survey research is employed to test these hypotheses. Previous researches, such as marketing, leisure, hedonic research, have been referenced to measure constructs. We collected data involving various experiences, and used 228 respondents to analyze these data using LISREL structural modeling. All internal consistency measures are greater than .70, which is above the level set by Nunnally(1978) of .70, so the scales demonstrate internal reliability. In the measurement model, the fit indices indicate satisfactory model fit. The proposed model was a good fit with the data, the hypothesized relationships were statistically significant. External (service provider) attribution had positive effects on psychological reactance to the switching barrier and justification had negative effects on psychological reactance to the switching barrier. Also, both reactance tendency and variety seeking had positive effects on psychological reactance to the switching barrier. And then psychological reactance to the switching barrier had significant effects on commitment to the present provider, negotiation intent to the switching barrier, and expectation to the alternative provider. In the final section, we discussed several limitations of our study and suggested directions for future research. We concluded with a discussion of managerial implications, including the potential to advance understanding switching barrier and implying an enhanced ability to satisfy target consumers of service field. 전환장벽은 제공자를 바꾸는 것을 어렵게 만드는 요인들로서, 장기적으로 소비자의 이탈을 막고 기업의 미래 이익에 기여한다는 측면에서 주로 논의되었다. 전환장벽이 표면적으로 이탈을 막는 것은 분명하지만, 심리적 반작용이론에 비춰볼 때 전환의 자유를 제약한다는 측면에서는 소비자들에게 부정적 영향을 줄 수 있다. 본 연구는 이러한 전환장벽의 부정적 영향을 구체화하기 위해, 전환장벽에 대한 심리적 반발을 중심으로 선행변수와 결과변수를 제안하고 있다. 먼저 전환장벽의 외적(서비스 제공자) 귀인과 정당성과 같은 장벽 자체의 특성, 그리고 반발성향과 다양성추구성향과 같은 개인적 특성이 전환장벽에 대한 심리적 반발에 영향을 주는 것으로 가정하였다. 전환장벽에 대한 심리적 반발은 현재 제공자에 대한 몰입, 전환장벽에 대한 협상의도, 대안적 제공자에 대한 기대에 영향을 주는 것으로 가정하였다. 이러한 가정들을 검증하기 위해 20~30대를 대상으로 228부의 데이터를 수집하였고, 구조방정식 모형을 이용하여 분석하였다. 연구결과, 예상한 바대로 전환장벽의 특성과 개인적 특성이 전환장벽에 대한 심리적 반발에 유의한 영향을 주고 있으며, 심리적 반발은 다시 현재 제공자에 대한 몰입, 협상의도, 그리고 대안적 제공자에 대한 기대에 유의한 영향을 주는 것으로 나타났다. 이러한 연구결과는 전환장벽이 고객과의 관계유지에 긍정적일 뿐 아니라, 한편으로 직간접적으로 미래성과에 부정적 영향을 줄 수 있음을 결과변수를 통해 보여주며, 또한 어떤 특성들이 이러한 부정적 영향에 더 기여할 수 있는지를 선행변수의 제안을 통해 발견하고 있다. 이는 전환장벽에 대한 다양한 시각이 부족했던 기존 연구를 보완하며, 전환장벽에 대한 시각의 확장을 통해 실무적 시사점도 함께 제시하고 있다.

중소기업 제품을 위한 RAMS 프로세스에서 Safety Barrier와 Barrier Function에 대한 연구

이창룡(Chang Long Li),정호형,이기서(Key Seo Lee) 한국철도학회 2013 한국철도학회 학술발표대회논문집 Vol.2013 No.5

본 논문은 중소기업 제품을 위한 RAMS 프로세스에서 시스템 정의의 안전장벽과 기능장벽의 정의로부터 시스템정의 방법과 위험분석방법에 대하여 연구하였다.RAMS 프로세스는 국제규격인 IEC 62278의 규정에 따라 V-Cycle의 컨셉, 시스템 정의, 리스크 분석, 시스템 요구사항, 디자인 및 수행, 제작, 설치 단계로 구성이 된다. 컨셉과 시스템 정의 단계에서는 기능안전부분을 safety barrier와 barrier function으로 분석하고 위험분석은 시스템 FMEA를 통하여 분석한다. 위험분석은 시스템정의와 응용환경을 기본으로 하고 있으므로 RAMS 프로세스에서 중요한 위치에 있다. This paper present RAMS process of Safety Barrier and Barrier Functions for the product of small and medium enterprise. RAMS process is consist of 12 phase in general. And this paper will outline 3 phases which will be used in the product of barrier systems. The 3 phases are concept, system definition and application conditions, risk analysis. In the concept and system definition phase this paper will use safety barrier and barrier function instead of functional safety, and risk analysis will use systematic FMEA methodology.

경험적 소비에서 장벽과 그 영향에 관한 연구 -접근가능성과 접근동인을 통한 이중적 영향을 중심으로-

정윤희,이종호 한국소비자·광고심리학회 2010 한국심리학회지 소비자·광고 Vol.11 No.2

This study defines the type of barrier and conducts the impact of barrier in experiential consumption. There are many studies on leisure constrains, but these researches have several limitations. First, these studies have overlooked different roles of barrier and dealt with the only negative aspects of barrier. Also, previous studies on leisure constraints show only few barriers. So, this study attempts to complement the lack of existing research and has purposes as follows. First, it is to show both the positive and the negative impacts that had been overlooked in the previous researches. Second, it is to propose the barrier traits derived from experience, unlike the barrier traits suggested in previous studies. Third, this research intends to find the effects which these various kinds of barriers have. But, because of the lack of research, the model of study was established by using qualitative research methods. Fourth, it is to verify the detail relationship through quantitative research. To achieve the goal of this study, the following research methods were used. For the first, the theoretical model was established through literature review, and then the detail effects were explored by using indepth-interview. Also, the results of indepth-interview were tested by using survey research method. Based on these test process, this study shows several meaningful results as follows. First, this study identifies the type of barrier, such as ‘barrier on equipment’, ‘barrier on time’, ‘barrier on place’, ‘barrier on knowledge/skill’, ‘barrier on knowledge/skill acquisition process’, ‘barrier on norm’, ‘barrier on the probability’. Unlike previous studies, these barriers include the various barriers to be measurable by multi-item. Second, this study shows how these barriers affect experience. Dropping accessibility toward the experience, barriers negatively influence on experience intention. And stimulating access-drivers toward the experience, barriers positively influence on experience intention. The accessibility includes physical accessibility (accessibility toward funds, accessibility toward time, accessibility toward ability, accessibility toward companion) and psychological accessibility. And in the access drivers, envy-exploration driver and arousal seeking driver were confirmed. These results provide new perspectives on barriers, and contribute to the academic development. Also, these results can be used practically in various fields related to the barrier. 이 연구는 경험적 소비에서 소비자들이 직면하는 장벽들에는 어떤 것들이 있으며, 이들이 어떤 영향을 발휘하는지에 대해 초점을 두고 있다. 대부분의 연구들은 경험적 소비 개별 분야에 있어서만 연구를 진행해오고 있기 때문에 그 기반이 되는 경험적 소비에 관한 연구는 부족하며, 장벽에 관한 연구 또한 경험적 소비분야 중 여가분야에서만 한정적으로 다뤄져 왔다. 또한 기존 여가 제약 연구는 경험에서 발생하는 다양한 장벽을 보여주지 못하고 있으며, 사람들이 여가에 참여하지 않는 이유를 탐색하는 과정에서만 장벽을 다루었기 때문에, 장벽이 가지는 다양한 영향에 대한 가능성을 간과하고 있다. 따라서 본 연구에서는 경험적 소비를 연구 범위로 하여 다양한 장벽 들을 밝히고, 장벽의 부정적 영향을 넘어 긍정적 영향까지 확장하여 보여주고자 하였다. 기존 연구를 참조하여 경험 장벽, 접근가능성, 접근동인, 경험의도를 중심으로 모형을 설정하고, 심층면접과 검증과정을 통해 상세한 내용과 관계를 확인하였다. 연구결과, 다항목으로 측정가능한 장비상의 장벽, 시간상의 장벽, 장소상의 장벽, 지식/기술상의 장벽, 지식/기술 습득과정 장벽, 규범상의 장벽, 확률상의 장벽 등이 경험 장벽으로 확인되었고, 이러한 경험 장벽은 자금 접근성, 시간 접근성, 능력 접근성, 동료 접근성과 같은 물리적 접근성과 심리적 접근성에 부정적 영향을 주고, 선망․탐험 동인, 감각추구동인과 같은 접근동인에는 긍정적 영향을 주는 것으로 나타났다. 이러한 연구결과는 장벽에 대한 새로운 시각을 제공해주며 장벽과 관련한 다양한 분야들에서 이론적 실무적으로 기여할 것이다.

태권도 수련의 참여동기가 장애요인 및 수련지속 의도에 미치는 영향

곽한병(Kwak Han-Pyong),송민규(Song Min-Kuy) 한국체육과학회 2009 한국체육과학회지 Vol.18 No.4

The purpose of this study was to examine the relationship of the participation motivation and barriers of taekwondo trainees to their intention of continuous training. The subjects in this study were 600 taekwondo trainees who resided in Gyeonggi Province and Seoul as of 2009. After self-administered questionnaires were prepared, 30 questionnaires each were sent to 10 selected taekwondo gyms located in different regions. And the answer sheets from 532 respondents were analyzed except for 68 incomplete ones. A SPSSWIN 16.0 program was employed to make a factor analysis, reliability analysis, correlation analysis, one-way ANOVA and standard multiple regression analysis. The findings of the study were as follows. First, the participation motivation of the taekwondo trainees had an impact on their barriers. Particularly, good use of leisure time affected all the barrier factors in a negative manner, and that was under the strong influence of family-related barriers, time barriers and social barriers. Health orientation exercised a significant influence on all the barriers, and was especially affected by social barriers, family-related barriers and personal barriers. Second, the participation motivation of the taekwondo trainees exercised an influence on their intention of continuous training. Good use of leisure time had a strong impact just on intention of continuous training, but health orientation didn't affect the barrier factors. It showed that the taekwondo trainees practiced taekwondo to take advantage of their free time rather than to seek after health promotion. Third, the barrier factors of the taekwondo trainees exerted an influence on their intention of continuous training. The environmental barriers, part of the barrier factors, had a negative impact on their intention of continuous training, and the social barriers affected it in a positive way. The time barriers exercised a negative influence on it.

Effectiveness of vegetation and sound wall-vegetation combination barriers on pollution dispersion from freeways under early morning conditions

Ranasinghe, Dilhara,Lee, Eon S.,Zhu, Yifang,Frausto-Vicencio, Isis,Choi, Wonsik,Sun, Wu,Mara, Steve,Seibt, Ulrike,Paulson, Suzanne E. Elsevier BV 2019 Science of the Total Environment Vol.658 No.-

<P><B>Abstract</B></P> <P>Pollutants in tailpipe emissions can be highly elevated around roadways, and in early mornings the pollution plume can extend hundreds of meters into surrounding neighborhoods. Solid sound walls and vegetation barriers are commonly used to mitigate noise, but they also help mitigate near-road air pollution. Here we assess the effectiveness of barriers consisting of vegetation only and of a combination of vegetation and a solid sound wall (combination barrier) in reducing pollution concentrations downwind of roads, under stable atmospheric stability and calm to light wind conditions. Because there was no practical (no barrier) control site in the area, we primarily compare the two barrier types to each other and explore the importance of atmospheric conditions. Using measurements collected with a mobile platform, we develop concentration decay profiles of ultrafine and fine particles, oxides of nitrogen (NO and NO<SUB>2</SUB>) and carbon monoxide downwind of a freeway in California with different barrier configurations and meteorological conditions. Diurnally averaged data collected with passive samplers indicate that pollution from morning rush hour has about equal impact as the entire remainder of the day, because of differences in atmospheric dispersion as the day progresses. Under calm and stable atmospheric conditions (wind speed <0.6 m/s); a vegetation-only barrier was more effective than a combination barrier with a total height that was somewhat lower than the vegetation-only barrier, by 10–24% in the first 160 m downwind. Under light winds (above ~ 0.6 but below 3 m/s) and stable conditions, the combination barrier was more effective than the vegetation barrier alone, by 6–33%, in the first 160 m from the barrier. The average particle size downwind of the vegetation-only barrier was larger than downwind of the combination barrier, indicating that particle deposition plays an important role in the reductions observed downwind of vegetation. Our results are consistent with the notion that at low wind speeds, vegetation acts as an effective barrier. Overall, adding vegetation alone or to an existing solid barrier results in lower downwind pollution concentrations, especially under low wind speeds when concentrations can be high.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Measurements were made around two barrier types under stable conditions. </LI> <LI> At higher wind speeds, the combination barrier was better than vegetation alone. </LI> <LI> Pollution reduction from vegetation was higher at low wind speeds. </LI> <LI> Deposition of particles onto even thin stands of trees is important. </LI> <LI> Pollution from a brief morning period equaled that from the remainder of the day. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>