Acute Effects of Ambient Air Pollution on Lower Respiratory Infections in Guangzhou Children of China

Daily concentrations of air pollution are associated with lower respiratory diseases. We investigated the short-term association of ambient air pollution with daily hospital admissions due to pneumonia among children aged 0−17 in Guangzhou city of China. Ambient air pollutants were all positively associated with children hospital admissions due to pneumonia of all ages. Significant associations were found for air pollutants except for inhalable particulate matter (PM) \(\le\)10 µm in aerodynamic diameter (PM10) in children of all ages. Increments of an interquartile range (IQR) (279.10µg/m3 and 28.42µg/m3, respectively) in the 7-day-average level of carbon monoxide (CO) and nitrogen dioxide (NO2) were associated with a 26.17% (95% confidence interval (CI) 1.40%-56.98%) and 25.09% (95%CI 0.54%-55.64%) increase in pneumonia hospitalizations for children aged 6−17, respectively. An IQR increase in CO concentrations was associated with a 15.15% (95%CI 4.34%-27.08%) increase in pneumonia hospitalizations for children aged 1−5. Daily cases of microbial detection for pneumonia were positively associated with daily NO2 concentration. The pneumonia hospitalizations due to Mycoplasma pneumonia, Flu A virus and Flu B virus, the predominant pathogenic microorganisms detected in children aged 0−5 are apparently associated with levels of PMs, CO, NO2 and O3.

Research on the Difference Between Recreational Walking and Transport Walking Among the Elderly in Mega Cities With Different Density Zones: The Case of Guangzhou City

Walking is the easiest method of physical activity for older people, and current research has demonstrated that the built environment is differently associated with recreational and transport walking. This study modelled the environmental characteristics of three different building density zones in Guangzhou city at low, medium, and high densities, and examined the differences in walking among older people in the three zones. The International Physical Activity Questionnaire (IPAQ) was used to investigate the recreational and transport walking time of older people aged 65 years and above for the past week, for a total of three density zones (N = 597) and was analysed as a dependent variable. Geographic Information Systems (GIS) was used to identify 300, 500, 800, and 1,000 m buffers and to assess differences between recreational and transport walking in terms of the built environment [e.g., land-use mix, street connectivity, Normalised Difference Vegetation Index (NDVI) data]. The data were processed and validated using the SPSS software to calculate Pearson's correlation models and stepwise regression models between recreation and transit walking and the built environment. The results found that land use mix and NDVI were positively correlated with transport walking in low-density areas and that transport walking was negatively correlated with roadway mediated centrality (BtE) and Point-of-Interest (PoI) density. Moreover, recreational walking in medium density areas was negatively correlated with self-rated health, road intersection density, and PoI density while positively correlated with educational attainment, population density, land use mix, street connectivity, PoIs density, and NDVI. Transport walking was negatively correlated with land-use mix, number of road crossings while positively correlated with commercial PoI density. Street connectivity, road intersection density, DNVI, and recreational walking in high-density areas showed negative correlations. Moreover, the built environment of older people in Guangzhou differed between recreational and transport walking at different densities. The richness of PoIs has different effects on different types of walking.

Estimating the Mosquito Density in Guangzhou city, China

Mosquito is a vector of many diseases. Predicting the trend of mosquito density is important for early warning and control of mosquito diseases. In this paper, we fit a discrete time mosquito model developed by Gong et al. in 2011, which considers the immature and adult stages, and weather dependent model parameters, to the Breteau Index and Bite Index data for Aedes aegypti in Guangzhou city, China in 2014, as well as the weather data for average temperature, precipitation, evaporation and daylight for the same period. We estimated the model parameters using the Markov Chain Monte-Carlo (MCMC) method. We find that many parameters are not identifiable. We revise and simplify the model so that the parameters of our new model are identifiable. Our results indicate that the model predicted mosquito prevalence agrees well with data. We then use the fitted parameter values against the Breteau Index and Bite Index data for Guangzhou city in 2017 and 2018, and show that the estimated parameter values are applicable for other seasons.

Impact of Social Work Services on the Resilience of Migrant Children

Purpose: This study examines the effectiveness of social work services designed to enhance resilience among migrant children in urban China. Methods: We selected four primary schools (i.e., two public and two private migrant schools) in the X District, Guangzhou City, China. A total of 461 valid samples were surveyed for analysis. Three regression models were employed to explain the influence of social work services on students’ resilience. Results: Social work services exert a positive and significant influence on the resilience of migrant children. Concretely, social work services in terms of educational activities, interest activities, and psychological counseling affected the resilience of migrant children after controlling for the impact of social capital, self-efficacy, and individual and household economic status. Moreover, students who participated in educational activities exhibit superior resilience. Discussion: Social work organizations should provide more participation opportunities and diversified service items to migrant children.

Effects of Physical Exercise Motives on Physical Health and Aerobic Fitness of Teenagers

Background: A good level of physical fitness helps teenagers maintain a good state in daily study and life and enables them to cope well with emergencies. We aimed to explore the influences of physical exercise motives on the physical health and aerobic fitness of teenagers. Methods: A total of 982 teenagers aged between 13 and 16 years in the four districts of Guangzhou City, China from January to December 2019 were selected randomly with the assistance of communities. Their physical exercise motives and exercise behaviors were investigated using a questionnaire survey, and their physical health indexes and aerobic fitness were assessed. The relationships of physical exercise motives and behaviors with physical health and aerobic fitness were analyzed. Results: Teenagers who have higher physical health scores show significantly increasing trends in their scores in exercise motives and different dimensions, exercise behaviors, and aerobic fitness scores (P<0.05). Physical exercise motives show significant correlations with exercise behaviors, physical health, and aerobic fitness. Moreover, exercise behaviors show significantly positive correlations with physical health and aerobic fitness (P<0.05). Physical exercise motives have a positive effect on exercise behaviors, physical health, and aerobic activities, and exercise behaviors have a positive effect on physical health and aerobic activities (P<0.05). Conclusion: The physical exercise motives of teenagers have positive and prediction effects on exercise behaviors, physical health, and aerobic fitness. Exciting physical exercise motives can promote the physical exercise behaviors of teenagers and improve their physical health and aerobic fitness.

Virome in adult Aedes albopictus captured during different seasons in Guangzhou City, China

Background The mosquito Aedes albopictus is an important vector for many pathogens. Understanding the virome in Ae. albopictus is critical for assessing the risk of disease transmission, implementation of vector control measures, and health system strengthening. Methods In this study, viral metagenomic and PCR methods were used to reveal the virome in adult Ae. albopictus captured in different areas and during different seasons in Guangzhou, China. Results The viral composition of adult Ae. albopictus varied mainly between seasons. Over 50 viral families were found, which were specific to vertebrates, invertebrates, plants, fungi, bacteria, and protozoa. In rural areas, Siphoviridae (6.5%) was the most common viral family harbored by mosquitoes captured during winter and spring, while Luteoviridae (1.1%) was the most common viral family harbored by mosquitoes captured during summer and autumn. Myoviridae (7.0% and 1.3%) was the most common viral family in mosquitoes captured in urban areas during all seasons. Hepatitis B virus (HBV) was detected by PCR in a female mosquito pool. The first near full-length HBV genome from Ae. albopictus was amplified, which showed a high level of similarity with human HBV genotype B sequences. Human parechovirus (HPeV) was detected in male and female mosquito pools, and the sequences were clustered with HPeV 1 and 3 sequences. Conclusions Large numbers of viral species were found in adult Ae. albopictus, including viruses from vertebrates, insects, and plants. The viral composition in Ae. albopictus mainly varied between seasons. Herein, we are the first to report the detection of HPeV and HBV in mosquitoes. This study not only provides valuable information for the control and prevention of mosquito-borne diseases, but it also demonstrates the feasibility of xenosurveillance. Graphical Abstract

The Impact of Impervious Surface Expansion on Soil Organic Carbon: A Case Study of 0–300 cm Soil Layer in Guangzhou City

Empirical evidence shows that the expansion of impervious surface threatens soil organic carbon (SOC) sequestration in urbanized areas. However, the understanding of deep soil excavation due to the vertical expansion of impervious surface remains limited. According to the average soil excavation depth, we divided impervious surface into pavement (IS20), low-rise building (IS100) and high-rise building (IS300). Based on remote-sensing images and published SOC density data, we estimated the SOC storage and its response to the impervious surface expansion in the 0–300 cm soil depth in Guangzhou city, China. The results showed that the total SOC storage of the study area was 8.31 Tg, of which the top 100 cm layer contributed 44%. The impervious surface expansion to date (539.87 km2) resulted in 4.16 Tg SOC loss, of which the IS20, IS100 and IS300 contributed 26%, 58% and 16%, respectively. The excavation-induced SOC loss (kg/m2) of IS300 was 1.8 times that of IS100. However, at the residential scale, renovating an IS100 plot into an IS300 plot can substantially reduce SOC loss compared with farmland urbanization. The gains of organic carbon accumulation in more greenspace coverage may be offset by the loss in deep soil excavation for the construction of underground parking lots, suggesting a need to control the exploitation intensity of underground space and promote residential greening.