To explore the effects of different types of forest environments for forest therapy, this study focused on forest resting environments. Seven representative forest resting environments found in field research in Beijing were used as independent variables and were shown to subjects by a virtual reality (VR) video. Stress level was used as the dependent variable, and blood pressure, heart rate, salivary amylase, and the Brief Profile of Mood States (BPOMS) were used as physiological and psychological indicators. A between-subjects design was used in the experiment. A total of 96 subjects were randomly assigned to each environment type, and only one type of forest resting environment was observed. Through the relevant sample t-test and one-way analysis of variance, the pre- and post-test data of the indicators were analyzed. This study found that all the seven different types of forest resting environments can produce stress relief effects to some extent. Different types of forest resting environments have different effects on relieving stress. The most natural environment does not have the most significant effect on stress relief. A water landscape has a positive effect on the relief of stress. The conclusions of this study are conducive to the better use of the forest environment for forest therapy services.

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The globalization of agricultural trade has dramatically altered global nitrogen flows by changing the spatial pattern of nitrogen utilization and emissions at a global scale. As a major trading country, China uses a large amount of nitrogen, which has a profound impact on global nitrogen flows. Using data on food production and trade between China and 26 other countries and regions, we calculated nitrogen inputs and outputs in food production ecosystem in each country. We estimated nitrogen flows in international food trade and analyzed their impact on nitrogen pollution in China. We divided nitrogen flows into embodied and virtual nitrogen flows. Embodied nitrogen is taken up by the plant and incorporated into the final food product, whereas virtual nitrogen is lost to the environment throughout the food production process and is not contained in the final food product. Our results show that China mainly imports food products from America and Asia, accounting for 95 % of all imported food. Asia (mainly Japan) and Europe are the main exporters of food from China, with Japan and the EU accounting for 17 and 10 % of all exported food, respectively. Total nitrogen inputs and outputs in food production in China were 55,400 and 61,000 Gg respectively, which were much higher than in other countries. About 1440 and 950 Gg of embodied and virtual nitrogen respectively flow into China through the food trade, mainly from food-exporting countries such as the USA, Argentina, and Brazil. Meanwhile, 177 and 160 Gg of embodied and virtual nitrogen respectively flow out of China from the export of food products, mainly to Japan. China's net food imports have reduced 720 and 458 Gg for nitrogen utilization and outputs, respectively, which accounted for 1.3 and 0.78 % of total nitrogen inputs and outputs in China. These results suggest that food trade in China has a profound effect on nitrogen flows and has greatly reduced environmental impacts on nitrogen pollution in China.

The concentration, sources and environmental risks of polycyclic aromatic hydrocarbons (PAHs) in surface water in urban areas of Nanjing were investigated. The range of ∑PAHs concentration is between 4,076 and 29,455 ng/L, with a mean of 17,212 ng/L. The composition of PAHs indicated that 2- and 3-ring PAHs have the highest proportion in all PAHs, while the 5- and 6-ring PAHs were the least in proportion. By diagnostic ratio analysis, combustion and petroleum were a mixture input that contributed to the water PAH in urban areas of Nanjing. Positive matrix factorization quantitatively identified four factors, including coke oven, coal combustion, oil source, and vehicle emission, as the main sources. Toxic equivalency factors of BaP (BaP) evaluate the environmental risks of PAHs and indicate the PAH concentration in surface water in urban areas of Nanjing had been polluted and might cause potential environmental risks. Therefore, the PAH contamination in surface water in urban areas of Nanjing should draw considerable attention.