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With the improvement of people's requirements for living environment, the effect of indoor radon radioactivity on health has been widely concerned. In this paper, taking a university in Shanghai as an example, indoor radon concentration and its related environmental parameters were measured in some of its rooms to understand the level of indoor radon concentration on its campus. The results showed that the average concentrations of student dormitory, office buildings, and academic buildings were 14.79±9.15 Bq/m3,22.67±5.72 Bq/m3, and 12.55±6.71 Bq/m3 respectively. Indoor radon was positively correlated with indoor temperature and humidity, and ventilation was also an effective method to reduce indoor radon.

Few studies pay attention to the possible associations between indoor VOCs and childhood asthma in Shanghai considering the effect of household ventilation. From March 2013 to December 2014, we collected air samples from 358 children's bedrooms in Shanghai, China. Information on childhood asthma, environmental exposures, and lifestyle behaviors was collected. Two-sample of Mann-Whitney U test, bivariate logistic regressions, and multiple logistic regression were used to obtain the association between VOCs and childhood asthma. Association analysis stratified by frequency of window opening during night was conducted to explore its possible effect on the target association. High concentrations of toluene and dodecane were significantly associated with childhood wheeze, and a high concentration of toluene was significantly associated with diagnosed asthma. In the bedrooms with low frequency of window opening during night, high concentrations of toluene, dodecane, and TVOC were significantly associated with childhood wheeze, and a high concentration of toluene was significantly associated with diagnosed asthma. Our results indicate that exposure to VOCs may be a risk factor for childhood asthma, especially in the bedrooms with poor ventilation during night. Family avoidance behaviors of household ventilation should be considered in the study of associations of household VOCs with childhood asthmatic symptoms.

Household dust mites (HDMs) are the important allergens causing allergic diseases in children. A predictive model can help us understand the concentration of HDMs in different areas of China to better prevent and control this kind of allergen. This study used 454 household inspection samples in childrens’ room obtained from China, Children, Homes, Health (CCHH) phase 2 study, conducted during 2013-2014. Spearman correlation and multiple logistic regression were used to explore the influencing factors of HDMs concentrations, by comprehensively considering residents’ lifestyle, building characteristics, environmental exposure, especially dampness-related exposures. This study used the Gradient Boosting Decision Tree(GBDT) algorithm to build the prediction model. The data from CCHH were used to established the prediction model. It was found that there were some differences in the influencing factors between two types of HDMs. The concentration of HDMs were found a significant correlation (p0. 9). This paper provides a reference for predicting the HDMs concentrations in children's bedrooms and the influence of the influencing factors.

In this paper, the CO2 (carbon dioxide) exhaled by indoor occupants was used as the tracer gas, and the variation of indoor CO2 concentration in the whole day was observed. Among the 454 samples, 114 and 345 valid samples were screened out which can be used to calculate the daytime and night ventilation rate by the tracer gas method through the sectioning method. The results indicated that seasonal differences in daytime average ventilation are greater than night average ventilation. The highest daytime- average ventilation was found in autumn, next was summer, there was the lowest ventilation in winter. According to the necessary fresh air rate when sleeping at night, night average ventilation rate of 30.1% of samples met the standard. The ventilation rates of different building characteristics were analyzed, residential location, construction age, living floor, room size, window structure, indoor dampness, and window opening habits were all included. The results revealed that the window opening habits was the most significant factor for natural ventilation. Both daytime and night average ventilation rate are basically in the ratio of 2:1 when the windows are opened and closed. moreover, there was higher impact of outdoor climate on daytime average ventilation when window was closed. Significant impact of window structure and indoor dampness on night average ventilation was observed when window was opened. Present study proposed the measurement and determination methods of ventilation when daytime activities of occupants were happened

Exposure of phthalate has adverse effects on child health. Currently, the field measurement on PAEs concentration in children’s bedrooms were limited, and the test of PAEs is laborious. Based on the data of home detection in 454 residences from March 2013 to December 2014 in Shanghai, the association of PAEs in children's bedroom and building characteristics, residents’ lifestyle and indoor environment characterization were built by Spearman correlation. According to the Spearman correlation coefficient method, the concentration of PAEs, such as residential area was significantly correlated with DMP, BBP and DiBP in children’s bedroom (sig 0), and the use of chemicals was significantly associated with DEP and DiBP in children’s bedroom (sig 0). Then a gradient-boosting decision tree model with higher prediction accuracy is established. The influencing factors of the studied PAEs were determined by comprehensive consideration of the current study and literature review. 11 influencing factors of PAEs concentrations from three aspects were finally established in this study. The training model of GBDT has a reasonable accuracy( R2>0.9). This paper provides a reference for the prediction of PAEs concentration in the residential bedroom and the influence degree of influencing factors.

Designing an economical, superior activity, excellent stability, and earth-rich catalysts is of crucial significance in the progress of electrochemical water splitting and still remains huge challenge to overcome. In this work, amorphous MoO2 with a porous nanostructure as a novel bifunctional electrocatalyst has been prepared by the hydrothermal method. This nanostructure has excellent HER/OER properties, in which the amorphous and porous states have a large number of vacancies and active sites exposed to the electrolyte. The as-prepared sample has been researched in detail via X-ray diffraction (XRD) and transmission electron microscopy (TEM). Electrochemical experiments show that when the current density reaches − 10 mA cm−2, the as-prepared samples need an overpotential of only about − 0.930 V (vs. RHE) in 1 M H2SO4 and − 0.777 V (vs. RHE) in 1 M KOH for HER, respectively. Furthermore, MoO2 exhibits an extremely overpotential of 2.414 V (vs. RHE) at 10 mA cm−2 in 1 M KOH for OER. It is believed that the amorphous and porous nanostructure remains a promising and efficient hydrolytic electrocatalyst. [ABSTRACT FROM AUTHOR]

After decades of development, the indoor environment in China has changed. A systematic review was conducted from peer‐reviewed scientific papers with field test data of indoor radon in China from 2000 to 2020 for three types of buildings. The mean concentrations of indoor radon for dwellings, school buildings, and office buildings are 54.6, 56.1, and 54.9 Bq/m3. The indoor radon concentration was related to seasons, climate regions, ventilation, decoration, and other factors such as soil and outdoor air. Colder seasons, especially in severe colder areas of China, newer decorated buildings, closed windows, and doors were all associated with higher indoor radon concentrations. Variables like climate region and ventilation showed statistical significance in the correlation analysis. Regarding the increasing trend of indoor radon concentration in China during the last two decades, further study of indoor radon is necessary especially for school buildings and office buildings, and will help access its environmental burden of disease in China more accurately. [ABSTRACT FROM AUTHOR]

Indoor ammonia (NH3) pollution has been paid more and more attention in view of its health risk. However, few studies have investigated the exposure level in the non‐occupational environment in China. This study systematically reviewed the indoor ammonia exposure level in different regions, the equivalent exposure concentration of different populations, and the factors that influence indoor air ammonia in residences, offices, and schools in China. The literature published in 1980–2019 from main databases was searched and detailed screened, and finally, 56 related studies were selected. The results illustrated that the median concentration of indoor air ammonia in residences, offices, and school buildings was 0.21 mg/m3, 0.26 mg/m3, and 0.15 mg/m3. There were 46.4%, 71.4%, and 40% of these samples exceeding the NH3 standard, respectively. The national concentrations and the equivalent exposure levels of adults and children were calculated and found to be higher than 0.20 mg/m3. The concentration of ammonia varied greatly in different climate zones and economic development regions. Higher concentrations were found in the severe cold zone and the regions with higher economic level. This review reveals a high exposure risk of indoor air ammonia and the crucial impact of human emission, indoor air temperature, new concrete, and economic level, suggesting further investigation on indoor air ammonia evaluation and health effects. [ABSTRACT FROM AUTHOR]

In this work, UV light activated multi-cycle photoelectric properties of TiO₂ and CdS/TiO₂ films in formaldehyde were researched. TiO₂ film was prepared by screen printing, CdS/TiO₂ compounded film was synthesized by SILAR method. XRD and FE-SEM was used to characterize the TiO₂ and CdS/TiO₂ samples. Multi-cycle photoelectric properties of TiO₂ and CdS/TiO₂ with uv light on and off were evaluated by testing the photocurrent. On one hand, under the same bias voltage, CdS/TiO ₂showed a higher photocurrent than that by TiO₂. The reason for this result should be ascribed to the compounded structure in CdS/TiO₂, with which the separation and transfer of photogenerated electron-hole pairs could be improved. On the other hand, with the testing cycle number increased, the photocurrent amplitudes of TiO₂ and CdS/TiO₂ increased. These results suggested that the time to reach a stable photocurrent value for TiO₂ and CdS/TiO₂ is much longer than one cycle time (300 S). To illustrate the increased photocurrent amplitude value cycle by cycle, the photocurrent of CdS/TiO₂ to a much longer time (more than 4000 seconds) was also tested. To explain these results, corresponding possible illustrations were presented.