Outdoor wind and thermal environments in residential areas are greatly affected by the distance between buildings. A short distance is conducive to providing shade, and a long distance can enhance ventilation between buildings. In this study, four cities with different latitudes in China (Guangzhou, Wuhan, Beijing, and Harbin) were selected to research the relationship between the distance between buildings and thermal environments of residential areas. The results show that (1) when the distance between buildings is small, it is easier for wind paths to form. Wind paths can strengthen the wind velocity. When the distance between buildings exceeds 40–50 m, the building density is small, the building’s resistance to the wind becomes smaller and smaller, and the wind speed will gradually increase. (2) When the distance is in the range of 20–50 m, the MRT (mean radiant temperature) rise rate of each city is similar. For every 10 m increase in the distance between buildings, the MRT increases by about 1.25 °C. (3) D = 50 m (D/H = 1.19) is an inflection point. When D is less than 50 m, within the range of 20–50 m, the smaller the D is, the lower the SET* (standard effective temperature) is, while when D is more than 50 m, the opposite trend is observed.

Currently, people in crowded indoor spaces are required to wear a variety of personal protective equipment to curb the spread of COVID-19. This study aimed to investigate the effects of wearing four types of personal protective equipment (unprotected, wearing masks, wearing face shield and wearing medical protective clothing) on human thermal perception and physiological responses in indoor crowded spaces in summer. The experiment was conducted in a climate chamber designed to simulate the indoor crowded spaces. Environmental parameters of climate chamber (air temperature, relative humidity and wind speed), physiological parameters of subjects (wrist skin temperature and pulse rate), and subjective perceptions (thermal sensation and thermal comfort) were collected during the experiment. The experimental results showed that medical protective clothing has the most obvious blocking effect on heat exchange between human and environment. Thermal sensation in state 4 (wearing medical protective clothing) was significantly (p < 0.05) higher than that in other states. The study of physiological parameters showed that the wrist skin temperature and pulse rate under different protection states increased with the increase of room temperature. Through regression analysis, the thermal sensation estimation model of protective personnel in indoor crowded spaces based on wrist skin temperature and pulse rate was established. The adjusted R² and RMSE of all models were above 82% and less than 1, indicating that the established thermal sensation model had a good prediction effect.

In the context of normalized epidemic prevention and control, the impact of masks and protective clothing on personal thermal comfort cannot be overlooked. To investigate the thermal comfort of outdoor personnel under various protective conditions, this study took Wuhan as an example and evaluated the outdoor thermal comfort of subjects under different protection and activity conditions through thermal environment monitoring, physiological measurements, and thermal comfort questionnaires. The results show significant differences in the PET thermal comfort baseline under various protective conditions. To address the problem that most areas have not yet established state-specific thermal comfort baselines, a State Outdoor Comfort Index (SOCI) model was developed to correct the insensitivity of PET indicators to clothing thermal resistance and metabolic rate. Finally, the performance of the SOCI model was evaluated through statistical indicators, demonstrating its good predictive capability. This study provides appropriate quantitative indicators to improve the thermal comfort of outdoor personnel.

In this paper, both onsite measurements of thermal parameters and a subjective questionnaire of thermal comfort were conducted to investigate thermal comfort of different age groups during the winter season. This study was performed in a rural area of Tianmen, a city of China’s hot summer and cold winter region. Indoor environmental parameters were measured and a total of 1440 questionnaire samples were collected. The volunteers were divided into four groups, i.e., children, young people, middle-aged people and old people. The results indicated that in a cold environment with the temperature below 6 °C, old people were the most sensitive to cold and in a warm environment with the temperature above 19 °C, children were the most sensitive to heat. The neutral SET* (standard effective temperature) of children, young people, middle-aged people and old people in winter was 21.3 °C, 20.8 °C, 23.9 °C and 24.7 °C, which indicated discrepancies of SET* among different age groups. The neutral SET* model of different ages was predicted based on Newton interpolation. This study revealed differences in indoor thermal comfort among different age groups and could provide useful guidance for creating thermal comfortable environment for different ages.

Fine particulate matter (PM_2.5) is directly associated with smog and has become the primary factor that threatens air quality in China. In order to investigate the variation patterns of PM_2.5 concentrations in various regions of Wuhan city across different time spans, we analyzed continuous monitoring data from six monitoring sites in Wuhan city from 2013 to 2017. The results showed that the PM_2.5 concentration from the various monitoring sites in the five-year period showed a decreasing trend. January, October, and December are the three months with relatively high mean monthly PM_2.5 concentrations in the year, while June, July, and August are the three months with relatively low mean monthly PM_2.5 concentrations in the year. The number of days with a daily mean concentration of 35–75 μg/m³ was the highest, while the number of days with a daily mean concentration of more than 250 μg/m³ was the lowest. PM_2.5 accounted for a large proportion of the major pollutants and is the main source of air pollution in Wuhan city, with an average proportion of over 46%.