Search Results (172)

Life expectancy in the United States varies significantly by region, a gap often explained by socioeconomic factors like income and education. However, the relative contribution of atmospheric exposures is less understood. We identify formaldehyde exposure and wet-bulb temperature as leading predictors of county-level life expectancy. Our analysis of 22,540 county-year observations (2012–2019) shows that formaldehyde ranked as the second-strongest predictor, surpassed only by educational attainment. Wet-bulb temperature, a physiological measure of heat stress, ranked sixth and was the leading meteorological predictor. We identified these patterns using XGBoost with SHAP analysis, integrating atmospheric exposures, livestock density, socioeconomic conditions, and smoking prevalence within an external exposome framework. These results suggest that air pollutants and heat stress provide predictive information beyond traditional socioeconomic indicators. Full article

Frost buildup on copper tube-fin heat exchangers reduces their performance in cold, humid conditions. Fin length plays a key role in balancing heat transfer and frost resistance. This study experimentally examines how fin length affects thermal and frosting behavior. Four heat exchangers with fin lengths of $15.1$ $\mathrm{m}$$\mathrm{m}$, $18.53$ $\mathrm{m}$$\mathrm{m}$, $20.3$ $\mathrm{m}$$\mathrm{m}$, and $23.5$ $\mathrm{m}$$\mathrm{m}$ were tested at 2 °C/1 °C dry-bulb/wet-bulb air temperature and $-6$ °C coolant temperature under constant static pressure. Results show that longer fins increase total heat transfer—peak capacity rose from 512 $\mathrm{W}$ to 566 $\mathrm{W}$—but reduce heat transfer per unit area by about 30%. Operating time before defrosting increased by 30.6%, from $45.7$ $\min$ to $59.6$ $\min$, due to lower frost density. Total frost mass grew, but unit-area frost decreased by 12.7%. During defrosting, longer fins achieved greater absolute airflow recovery (from 195 to 213 ${\mathrm{m}}^3$h⁻¹), though defrosting efficiency per gram of frost declined. Short fins (15 $\mathrm{m}$$\mathrm{m}$) suit space-limited systems needing high surface efficiency. Long fins (23 $\mathrm{m}$$\mathrm{m}$) benefit large systems requiring long run times and strong post-defrost performance. Medium lengths (17 $\mathrm{m}$$\mathrm{m}$ to 20 $\mathrm{m}$$\mathrm{m}$) offer a practical balance for general use. These findings support better heat exchanger design in frost-prone applications. Full article

Background/Objectives: Since June 2025, Japan has mandated countermeasures to prevent outdoor laborers from developing heat-related illness at work. However, the extent to which preventive behaviors can reduce the actual heatstroke risk has not been quantified. The present study aimed to (i) project future trends in the daily number of heat-related ambulance transports in the working population under climate change, and (ii) evaluate the population-level preventive impact of workplace-adopted preventive behaviors using effect estimates from observational data. Methods: Using daily maximum wet-bulb globe temperature, a long-term future projection of heat-related ambulance transports was performed in the working population. A cross-sectional survey was carried out to infer the effect size of behavioral interventions. The effectiveness of taking preventive behaviors was evaluated by increasing the coverage rate of workers adhering to all four behaviors (current: 23%): (i) regular hydration, (ii) use of an air-cooling vest, (iii) checking their own health condition before work, and (iv) recognizing warning signs. Theoretical scenarios in which workplace instructions to workers or teams increased adherence by 50%, 100%, and 300% relative to baseline were considered, corresponding to coverage rates at 34%, 45%, and 91%, respectively, and we evaluated the associated reduction in heatstroke risk. Results: Many future years were projected to have higher annual levels of heat-related ambulance transports than the median value from 2018–2024, indicating a long-term increasing trend. Even when all four possible countermeasures were implemented at an additional 50%, 100% or 300% from the current rate, the expected relative risk reduction in transports was 3.2%, 6.3%, and 19.0%, respectively, indicating only a small effect on future projected heat-related illnesses. Conclusions: The number of heat-related ambulance transports is expected to increase; however, the relative risk reduction with behavioral intervention is likely limited. A fundamental overhaul of working regulations and environment (e.g., drastic shift in working hours to earlier morning) is required via adaptation policies, and mitigation of climate change is vital. Full article

This study investigates microclimatic variation across four environmentally and socially vulnerable neighborhoods in Philadelphia, utilizing ground-based measurements to assess urban heat (UH) and heat stress (HS). HS metrics, specifically Wet-Bulb Globe Temperature (WBGT) and heat index (HI), were calculated from UH measurements, including dry bulb and globe temperature, relative humidity, and wind speed. The methodology incorporates statistical modeling to identify significant predictors of HS, with street orientation (north–south and east–west) emerging as a key determinant, while categorical shade conditions were not statistically significant. Notably, Kingsessing exhibited lower HS and a unique humidity profile, whereas temperatures in Point Breeze and Grays Ferry and Hunting Park were consistently elevated. The research demonstrates that neighborhood-scale measurements can reveal critical spatial differences in UH and HS that are helpful in customizing mitigation strategies to specific communities. The approach is adaptable for integration with public health and emergency response initiatives, supporting data-driven decision-making for local governments and community-based organizations. Although assessment of physiological metrics and sampling during peak heat periods were not possible, overall, the study provides a practical framework for addressing urban heat vulnerability and underscores the importance of context-specific, community-engaged solutions to protect at-risk populations from extreme heat impacts. Full article

Background: Symptom scales are routinely used in sport during concussion screening and return-to-play. Limited research has explored the presence of concussion symptoms in the absence of a diagnosed concussion. This study analyzed concussion symptom scores in concussed vs. non-concussed football players after football activities and evaluated the effect of field of play variables. Methods: NCAA Division I football players with (n = 9) and without (n = 30) diagnosed concussion completed concussion symptom scales (C3 Logix) following practice for 1 week. Wet bulb globe temperature (WBGT), play duration, equipment, and location (inside/outside) were recorded. Mixed models analyzed the effect of day, WBGT, equipment, location, and play duration on concussion-like symptoms in non-concussed players and determined the time course of symptom relief in concussed players. Results: Fatigue or low energy (27.6%), neck pain (16.8%), feeling slowed down (14.8%), and headache (12.8%) were most reported. In non-concussed players, total symptoms scores were higher early in the week (Monday/Tuesday) and decreased throughout the week (p < 0.01). No effect of play duration (p = 0.49), WBGT (p = 0.12), equipment (p = 0.40), or location (p = 0.83) was found. Symptom scores were greater in the concussed vs. non-concussed groups on days 1–3. Conclusions: Football players report concussion-like symptoms in the absence of a concussion diagnosis, particularly following the first few practices after a game. Full article

Winter cities face the dual pressures of climate change and population aging, urgently requiring a shift from a singular focus on winter protection toward a development model adaptable to both winter and summer conditions. This shift is essential to enhance social resilience and safeguard the health of all age groups. This case study investigates how the thermal environment of life-sustaining streets in winter cities correlates with older adults’ daily activities. Employing Spearman correlation analysis, a heat exposure–pedestrian flow coupling matrix, and a comprehensive risk diagnostic model, the research analyzes the spatiotemporal variation patterns and underlying drivers of the street thermal environment. The key findings are: (1) All 15 surveyed streets exhibited Wet Bulb Globe Temperatures (WBGT) exceeding 28 °C during peak activity hours, with afternoon values (17:00–19:00) up to 2.7 °C higher than morning values. (2) On East Chaoyang Road, despite building shade and a high Visible Green Index (39.68%), the WBGT ranked second highest. This condition is attributed to a critically low average wind speed of 0.69 m/s (significantly below the city’s summer average of 2.67 m/s) and the widespread use of low-albedo asphalt, which collectively trap heat and negate the benefits of shading. (3) Using a dual-dimensional diagnostic framework, four streets were identified as dual-pressure streets with their combination of high elderly pedestrian flow (exceeding 126 persons/h) and high thermal risk (WBGT > 29 °C), marking them as priority intervention units. Based on these findings, the study proposes categorized street retrofit strategies that synergistically integrate climate adaptation and aging-friendliness. This provides an actionable, evidence-based foundation for planning decisions to support the sustainable renewal of winter cities amid climate change and population aging. Full article

This study analyzed how climate variability affects lactation yield and reproduction in Holstein cows in a continental climate. It specifically compared Wet-Bulb Temperature (T_wb) with the standard Temperature–Humidity Index (THI). We conducted a retrospective study on a dairy farm in Konya, Türkiye, analyzing a total of 144 complete lactation records from a herd of 90 cows calving between 2022 and 2023. To rule out nutritional factors, a consistent TMR diet without pasture access was maintained in both years. Average Daily Milk Yield (ADMY) was calculated to adjust for lactation length. Climatic data showed a distinct contrast. Ambient temperatures and THI were similar between years (p > 0.05). However, 2022 was characterized by “humid heat” (high T_wb), while 2023 presented a “dry heat” profile with significantly lower T_wb (p < 0.001). This difference significantly impacted performance. Cows in the 2023 group produced much higher milk yields (50.55 ± 3.01 kg) than the 2022 group (30.74 ± 0.81 kg) (p < 0.001). Unexpectedly, milk yield peaked during the Autumn and Summer seasons of the low-humidity year. In contrast, fertility declined with thermal load. Poor winter fertility suggested a “carry-over” effect of previous heat stress. These findings show that T_wb is a better indicator of thermal comfort than THI in continental climates. Furthermore, low humidity can significantly reduce the negative impact of heat on milk production. Full article

People living in India are experiencing some of the hottest summers on the planet. Conditions are particularly harsh in Indian cities, like Kolkata, where high temperatures are combined with high humidity. Understanding how conditions in Kolkata have evolved could provide an important addition to the growing study of the problems facing megacities in the hot, humid tropics. Yet in Kolkata, this understanding is obscured by different, often incompatible, methods of assessing the intensity of heat stress. This narrative review considers the problems encountered when attempting to develop a clear understanding of past increases or even to quantify current conditions using conventional meteorological or remote sensing data. Rather than trying to arrive at a precise quantification of how much hotter it is now in Kolkata than in the past, we argue for more fine-grained, individual-level understanding of how heat is experienced. An example of this approach is provided by a study that used telemetric devices to continuously monitor the temperature and humidity to which elderly residents of slum areas in Kolkata were exposed during 24h periods as they went about their daily lives. This study indicates that individuals experience a diversity of heat conditions that are inadequately represented by outdoor temperatures. Living in dwellings where indoor temperatures are often hotter than outdoor temperatures, the daily heat stress experienced by this vulnerable group varies between conditions that are stressful but endurable to those that approach the limits of human heat tolerance. Given the likelihood of even hotter environments in the future, urban planners will need access to more comprehensive heat studies, focusing on continual monitoring of heat stress and physiological responses of individuals from different walks of life. Full article

A dew-point evaporative air cooler incorporating a novel segmented heat exchange design, demarcated according to the humidity state of moist air, is proposed. The system employs a porous fibrous material to create a wetted evaporative surface, which is continuously maintained in a moistened condition through a self-wicking water supply mechanism to enhance latent heat transfer. Circular fins are installed on the heat exchanger’s partition surface once the moist air reaches saturation, thereby improving sensible heat exchange between the dry and wet channels. The performance of a prototype was evaluated under controlled conditions in a standard enthalpy chamber. Experimental results indicate that, under typical summer conditions (inlet dry-bulb and wet-bulb temperatures of 33.8 °C and 25.4 °C, respectively), with an air mass flow ratio of 0.7 and an air velocity of 1.5 m/s, the wet-bulb effectiveness reaches 114.4% and the dew-point effectiveness achieves 84.8%. The maximum temperature reduction occurs in the sensible heat exchange section, reaching up to 6.1 °C, demonstrating its substantial sensible heat recovery capability. The device exhibits an energy efficiency ratio (EER) ranging from 9.1 to 31.8. The proposed compact configuration not only enhances energy efficiency but also reduces material costs by approximately 15.4%, providing a valuable reference for the future development of dew-point evaporative cooling systems in residential buildings. Full article

Historic arcades in shaded street canyons may act as passive microclimate infrastructure. We monitored paired arcade–open points along two arcaded streets in Haikou, China, under clear summer conditions, recording hourly microclimate from 09:00 to 21:00. From these data we derived mean radiant temperature (Tmrt) and the Universal Thermal Climate Index (UTCI), tested main and interaction effects of space (arcade vs. open) and orientation (east–west vs. north–south), examined relations with sky view factor (SVF), and quantified exceedances of health-relevant thresholds using wet-bulb globe temperature (WBGT) and degree-hours. Arcades consistently lowered thermal exposure, with the largest benefits around midday–afternoon; the daily mean UTCI reduction was ~4.4 °C relative to adjacent open points. Orientation modulated benefits: east–west segments showed larger marginal reductions, and orientation differences were markedly compressed beneath arcades. SVF correlated positively with Tmrt and thermal stress but contributed little additional explanatory power after accounting for space and orientation, indicating geometric shielding as a primary mechanism. High-risk WBGT windows (≥32 °C) were strongly reduced under arcades, and day–night degree-hour summaries indicated net improvement. We conclude that historic arcades provide measurable thermal protection while preserving urban form, supporting their dual role as cultural heritage and passive climate-adaptation assets. Full article

This study looks into the parameters that affect the heat transfer coefficient (h₂) on the wet surfaces of vertical tube indirect evaporative coolers (VTIEC). An experimental platform was used to investigate the impact of secondary-to-primary airflow ratios (AFR) and spray water density on the HTC. The findings show that raising the primary air temperature drop, expanding the outside dry-bulb and wet-bulb temperature differences, and decreasing the air-to-water ratio improve heat transmission. The HTC of the wet sides ranged from 34.79 to 924.5 W/(m²·°C) throughout testing. To achieve optimal performance, aim for a spray water density of 2.07 to 3.46 m³/(m²·h), an AFR of 0.5 to 0.6, and a primary air temperature drop of at least 6 °C. These factors help keep the h₂ above 350 W/(m²·°C). Full article

Permeable pavement is commonly used for urban stormwater management and urban heat island mitigation. It has been proven that permeable pavement has such benefits; however, the clogged permeable pavement could lose its function, and there are relatively few studies on its long-term monitoring. This study monitored an in-use permeable sidewalk in central Taipei City, Taiwan, and presented its four-year performance. In the study area, the permeable sidewalk occupies nearly half of the drainage area. The onsite data showed that the average runoff reduction rate in the first year (2021) was 41.2% but decreased to 28.8% in the fourth year (2024). The differences in runoff reduction rate between different rainfall patterns are also discussed. If the permeable pavement is not cleaned, it might lose its permeability after 7 years. The results of the surface temperature monitoring show that the average surface temperature of permeable pavement is maintained at 28.8 °C over the four-year period, whereas the surface temperature of impermeable pavement increases annually. This finding verified that permeable pavement is helpful in stabilizing surface temperatures in urban areas, thereby combating the warming environment. In addition, Wet Bulb Globe Temperature (WBGT) was tested in this study. The results of WBGT showed that the WBGT above the permeable pavement is lower than that on impermeable pavements by about 1–2 °C from 12 p.m. to 16 p.m. This implies that permeable pavement may contribute to a comfortable thermal environment for the public. The results of this study provide crucial information for maintaining permeable pavement and enhancing its beneficial functions. Full article

Background: Elevated global temperatures increase the risk of heat-stroke among athletes exercising in hot conditions. Japanese high school baseball tournaments occur during peak summer, raising concerns regarding heat-related health issues. We examined whether the color of footwear and legwear affects lower-limb temperature, exploring approaches to prevent heat-related health problems. Methods: Eight mannequin legs were fitted with shoes, socks, and baseball stirrup socks in white or black combinations. Plantar and shin surface temperatures were recorded for 120 min on both dirt and artificial turf at wet-bulb globe temperatures above 30 °C and compared across color combinations. Reflectance spectra of shin legwear were also measured. Results: Plantar and shin surface temperatures increased under all conditions. On the dirt field, mannequins wearing all-black gear (shoe, sock, and baseball stirrup sock) exhibited plantar temperatures exceeding 45 °C and shin temperatures over 50 °C. The highest shin temperature occurred with the white shoe/black baseball stirrup sock combination. Temperature increases were smaller for all-white items compared with all-black items. Reflectance spectra showed that white baseball stirrup socks strongly reflected both visible and infrared light. Conclusions: Footwear and legwear color significantly influence lower-limb temperature increases during baseball games in summer heat, especially when wearing all-black items. White gear may help prevent heat-related health problems and improve performance in baseball and other outdoor sports. Full article

Besides oral temperature, meteorological parameters are expected to be relevant for mouthpiece temperature, potentially influenced by the material, surface area and weight of the bit. This study measured the temperature of the mouthpieces at the corner of the mouth while they were in use on 58 carriage horses during the four 2024 seasons. Stainless steel, copper, and copper–steel bits were tested in three shapes: Butterfly Liverpool, Liverpool, and Loose Ring Snaffle with four rings. Additionally, surface temperatures of inner thighs, the ground, and buildings were measured using infrared thermography as well as meteorological parameters. Mouthpieces of copper bits reached the highest median temperatures of all materials over all months (31.9 °C) and in August (34.5 °C). In February, the air temperature (median 12.45 °C) was cooler than mouthpiece temperatures (steel median 21.8 °C, copper median 26.4 °C). Mouthpieces of copper–steel Liverpool bits were significantly warmer than those of steel Liverpool bits (+1.1 °C, p < 0.026) at wet bulb globe temperatures > 25 °C. Maximum mouthpiece temperatures of steel Butterfly Liverpool bits showed a weaker correlation (Spearman Rho 0.8) with wet bulb globe temperature categories than both steel Liverpool bits and steel Loose Ring Snaffle bits, which demonstrated a full correlation (Spearman Rho 1). Concerning mouthpiece temperatures, bit material, shape, and weather conditions should be considered when selecting bits to ascertain impacts on equine welfare. Full article

Water distribution and pumping systems consume a large share of energy in metro HVAC operations and remain a major challenge to energy-efficient performance. This study, grounded in a practical metro project, investigates four control strategies for chilled water systems, focusing on chiller sequencing, pump frequency modulation, and variable flow regulation. A dynamic system model was developed using Dymola to simulate and evaluate the performance of each strategy. The results indicate that Strategy 2, which integrates real-time outdoor weather parameters into the frequency control logic, enhances operational stability and maintainability while achieving a 4.42% reduction in total energy consumption compared to the baseline. Strategy 4 employs a genetic algorithm to optimize chiller load distribution, resulting in improved system efficiency and energy savings of up to 8.62%. Further analysis reveals that chillers account for approximately 80% of the system’s total energy consumption, underscoring their central importance in system-wide energy optimization. Additionally, cooling towers show significant energy-saving potential under low wet-bulb temperatures. A 1 °C decrease in wet-bulb temperature results in an estimated 7% reduction in energy use. These findings offer quantitative insights and practical guidance for the low-carbon optimization of metro chilled water systems. Full article