도시숲 내 범용열기후지수(Universal Thermal Climate Index: UTCI)와 인체의 생리적, 주관적 반응 = The UTCI (Universal Thermal Climate Index) in Urban Forests and Physiological and Subjective Responses of the Human Body

국문 초록 (Abstract)

본 연구의 목적은 도시숲 내 미기후 요소를 반영한 UTCI(Universal Thermal Climate Index)를 산출 후, 인체의 생리적·주관적 반응과 비교하고 봄철 도시숲 활용에 적정한 행동성 체온 조절 범위 도출을 하는 것이다. 2024년 4월 2일에서 5월 27일까지 충청북도 C 대학교 학술림인 도시숲에서 미기후 요소 측정과 청년층 6명, 장년층 6명, 이용객 대상의 현장 실험이 진행되었다. 피험자는 평균 피부온 산출을 위해 실험 기간 중 2회 피부온 측정과 숲에서 걷기를 진행하며 주관적 열감각에 대하여 응답하였으며, 이용객은 주관적 열감각과 착의량, 운동강도에 대한 설문에 응답하였다. 그 결과, 봄철 도시숲 내 UTCI 지수는 평균 20.26℃인 열중립 상태로 파악되었으며 피험자의 열정서는 서 있을 때와 활동 시 30분 후 약간 불쾌하다는 응답 1회(4.2%)을 제외하고 23회(95.8%) 쾌적하다고 응답하였다. 이용객은 열정서 53명(98.1%)이 쾌적하다고 응답하였으며, 열내성 52명(96.3%)이 현재 열적 상태를 확실하게 견딜 수 있다고 응답하여 UTCI 지수와 주관적 열 쾌적감과 일치하는 경향을 보였다. 피험자의 평균 피부온은 청년층 31.40(±1.17)℃, 장년층은 31.31(±.77)℃로 나타났으며, 집단 간 신체 부위별 평균 피부온 차이는 목, 어깨, 손은 차이가 없었으나 정강이의 경우 두 집단 간 유의한 차이가 있었다(p=.032). 그리고 활동별 평균 피부온과 열지각의 상관관계는 야외 활동 시 30분, 걷기 활동 20분 이후부터 유의미한 상관관계가 나타나지 않았다. 이는 산림치유를 위한 실외 활동 시 30분 이상 노출되면 열적 평형 상태에 이를 것으로 예측된다. 또한, 도시숲 이용객의 착의량과 운동강도를 파악한 결과, 착의량은 평균적으로 0.61clo, RPE 10~13까지 열 쾌적감을 느끼는 것으로 파악되었다. 본 연구를 통해 생활권 도시숲이 국민의 쾌적한 치유 활동과 건강증진 장소로 확장되는 것에 기초자료가 될 것으로 기대한다.

다국어 초록 (Multilingual Abstract)

This paper aims to study the Universal Thermal Climate Index (UTCI) by incorporating microclimate elements within urban forests, compare it with physiological and subjective human responses, and derive the behavioral temperature control range suitable for the utilization of urban forests in spring. From April 2 to May 27, 2024, microclimate parameters were measured within the urban forest, an academic forest at C University in Chungcheongbuk-do, and a field experiment is conducted involving 6 young adults, 6 elderly individuals, and other visitors. To determine the mean skin temperature, participants measured their skin temperature twice during the experiment and walked in the forest while reporting subjective thermal sensations. Participants also completed questionnaires regarding subjective thermal sensation, clothing insulation, and Rating of Perceived Exertion (RPE).
The results indicate that the UTCI in the urban forest during spring averaged 20.26℃, which is classified as thermally neutral. According to subject responses, 23(95.8%) reported feeling comfortable while standing and engaging in physical activity, with only 1(4.2%) reporting feeling slightly uncomfortable after 30 minutes. The majority of visitors 53(98.1%) reported feeling comfortable, and 52 (96.3%) indicate they could comfortably endure the current thermal conditions, demonstrating a high degree of alignment between the UTCI and subjective thermal comfort.
The mean skin temperature of participants is 31.40 ℃(±1.17) for the young adult group and 31.31 ℃(±0.77) for the elderly group. No significant differences are observed in mean skin temperature by body part between groups for the neck, scapula, and hands, but a significant difference is found in shin temperature (p = .032). Additionally, a significant correlation was found between mean skin temperature, body skin temperature, and thermal perceptual after 20 minutes of walking, which is 30 minutes post-outdoor activity. This suggests that thermal equilibrium is achieved after more than 30 minutes of exposure during forest therapy activities.
Furthermore the investigation into the clothing insulation and exercise intensity of urban forest visitors revealed that the average clothing insulation is 0.61 clo, and a RPE of 10 to 13 corresponded with thermal comfort. It is anticipated that this study will provide foundational data for expanding urban forests in residential areas into spaces conducive to comfortable forest therapy activities and health promotion.

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