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The climate of Yangtze River Basin in China is cold and humid in winter. Conventional air-conditioning systems may cause high energy consumption and uncomfortable microclimatic conditions especially for lower body of indoor occupants. This study investigated four personalized seat heating systems, in a typical office room in Shanghai during winter, based on heated floor panels including heated floor panels + ordinary chair (HF-OC), heated floor panels + insulated chair (HF-IC), heated floor panels +insulated chair and leg box (HF-IC-LB) and overall personalized heating (OPH). The surface temperature of walls and heated floor panels, and the indoor air temperature at different positions were recorded with thermocouples. The hourly energy consumptions of the proposed personalized seat heating systems were measured and compared with a conventional split type air conditioner. Questionnaires of thermal sensation and comfort were carried out among 10 university students. Compared with HF-OC, HF-IC could improve the thermal comfort to a certain extent, while HF-IC-LB provided the optimal thermal micro-environment for the lower body other than other body parts. The OPH systems were proven effective to provide satisfactory thermal environment for all body parts at lower indoor temperature (12–16°C) with much less energy consumption than room air conditioners. [ABSTRACT FROM AUTHOR]

Although the environment can greatly influence an individual's sleep quality, China is yet to conduct comprehensive research on the topic. This study investigated the bedroom environment and sleep quality of 41 households during summer in Shanghai. Bedroom environments were comprehensively evaluated through environmental perception questionnaires filled by participants after waking up every morning. Parameters, such as air temperature, relative humidity, CO 2 concentration, and noise level were continuously monitored. Furthermore, participants' sleep quality was observed using both subjective questionnaires and physiological measures. Environmental measurements showed that the most comfortable air temperature and relative humidity was 24.8 °C and 64%, respectively. Physiological measurements showed that the average duration of slow wave sleep (SWS) and sleep efficiency (SE) was 73.8 min and 86.7%, respectively. Additionally, SWS was negatively correlated with air temperature (r = −0.377, p = 0.015) and CO 2 concentration (r = −0.362, p = 0.02), and SE was negatively correlated with noise level (r = −0.32, p = 0.042). The subjective and objective results consistently indicated that higher air temperature, CO 2 concentration, and noise level leads to poor sleep quality in summer. In addition, air temperature and CO 2 concentration had a greater impact on the sleep quality of males, while noise level had a greater impact on the sleep quality of females. • Questionnaires and measurements were combined to figure out the relationship between environment and sleep quality. • Environmental factors and environmental perception votes showed a good linear relationship. • During sleep period, the most comfortable air temperature and relative humidity were 24.8 °C and 64%, respectively. • Air temperature and CO 2 level had a greater impact on males' sleep, while noise level had a greater impact on females'. [ABSTRACT FROM AUTHOR]

The threshold effect in the relationship between impervious surfaces and water quality has been a focus in past decades, but little attention has been paid to how the threshold effect changes during a rapid urbanization period. This study reveals the temporal variation of threshold effect in the relationship between the percentage of total impervious area (PTIA) and water quality indicators in a reticular river network area in Shanghai, China. The PTIA was surveyed and defined using the ISC method (impervious surface coefficients). A segmented regression model was used to disclose the non-linear relationship between PTIA and water quality. It is confirmed that the threshold effect was different in terms of water quality indicators, but the effect size became smaller as the threshold increased with urbanization level during the period of 1989–2010. Meteorological conditions make influence on the threshold effect, it can be found that the effect is more significant under higher air temperature conditions, while in the lower temperature situation, there is no significant threshold effect. Image 1 • Non-linear relationship is disclosed between PTIA and water quality. • Threshold effect is different in terms of water quality indicators. • The threshold increases with urbanization level. • Threshold effect becomes less apparent and may disappear in the near future. There is an obvious threshold effect between impervious surfaces and water quality, but the threshold effect decreases over time. [ABSTRACT FROM AUTHOR]