An analysis of influential factors on outdoor thermal comfort in summer

Abstract

A variety of research has linked high temperature to outdoor thermal comfort in summer, but it remains unclear how outdoor meteorological environments influence people's thermal sensation in subtropical monsoon climate areas, especially in China. In order to explain the process, and to better understand the related influential factors, we conducted an extensive survey of thermally comfortable conditions in open outdoor spaces. The goal of this study was to gain an insight into the subjects' perspectives on weather variables and comfort levels, and determine the factors responsible for the varying human thermal comfort response in summer. These perceptions were then compared to actual ambient conditions. The database consists of surveys rated by 205 students trained from 6:00 am to 8:00 pm outdoors from 21 to 25 August 2009, at Nanjing University of Information Science & Technology (NUIST), Nanjing, China. The multiple regression approach and simple factor analysis of variance were used to investigate the relationships between thermal comfort and meteorological environment, taking into consideration individual mood, gender, level of regular exercise, and previous environmental experiences. It was found that males and females have similar perceptions of maximum temperature; in the most comfortable environment, mood appears to have a significant influence on thermal comfort, but the influence of mood diminishes as the meteorological environment becomes increasingly uncomfortable. In addition, the study confirms the strong relationship between thermal comfort and microclimatic conditions, including solar radiation, atmospheric pressure, maximum temperature, wind speed and relative humidity, ranked by importance. There are also strong effects of illness, clothing and exercise, all of which influence thermal comfort. We also find that their former place of residence influences people's thermal comfort substantially by setting expectations. Finally, some relationships between thermal perception and amount of exercise, thermal experience, mood, clothing, illness and microclimate, etc., are established. Our findings also shed light on how to resist or adapt to outdoor hyperthermic conditions during summer in subtropical monsoon climate areas.

A new method to assess spatial variations of outdoor thermal comfort: Onsite monitoring results and implications for precinct planning

“…Some previous Asian urban micro-climate researchers were also very active, for instance, Ng et al [11] investigated urban human thermal comfort in Hong Kong, Lin and Hwang [37,38] in Taiwan, Thorsson et al [21] and Knez et al [39] investigated Japanese urban public places, Jeong et al [40] conducted similar studies in Korea; and for Mainland China, there were related investigations in Nanjing [41], Wuhan [42,43] and Tianjin [44].…”

Weather Regulated Cattle Behaviour on Rangeland

“…Solar radiation, atmospheric pressure, maximum temperature, wind speed and relative humidity determine the outdoor comfort level, as Yin (2011) suggested that a strong relationship may exist between microclimatic and comfort conditions. In the present work, biometeorological observations were carried out on Hungarian Grey cattle.…”

“…The effects of environmental factors, such as temperature, humidity and wind speed, which all impact on the animals, need to be examined in a broad context (Anda et al, 2010;Lovelock, 2010;Yin and Zheng, 2011). Previous zoometeorological observations pointed out that grazing cattle react differently to various weather conditions (Malechek and Smith, 1975).…”

Experimental study on skin temperature and thermal response of the foot-bather

“…The feet, as the distal extremities of human body, consist of massive capillaries [12], and therefore, local thermal exposure of foot has a significant impact on overall human thermal responses [13]. Since thermal responses of human body are difficult to be reconstructed, researchers have performed a great number of studies to find how occupants feel and adapt to inhomogeneous and dynamic environments [14], including experimental investigations carried out in public buildings [15,16], vehicles, and outdoors [17,18], which aim to explore relations between human thermal responses and thermal environment parameters. In addition, the thermal comfort due to local thermal exposure has been extensively investigated in the air environment based on heat transfer process [19][20][21], psychology [22][23][24][25] and physiology [26][27][28].…”