A top-down approach was employed to estimate the influence of lockdown measures implemented during the COVID-19 pandemic on NOx emissions and subsequent influence on surface PM2.5 and ozone in China. The nation-wide NOx emission reduction of 53.4% due to the lockdown in 2020 quarter one in China may represent the current upper limit of China's NOx emission control. During the Chinese New Year Holiday (P2), NOx emission intensity in China declined by 44.7% compared to the preceding 3 weeks (P1). NOx emission intensity increased by 20.3% during the 4 weeks after P2 (P3), despite the unchanged NO2 column. It recovered to 2019 level at the end of March (P4). The East China (22°N - 42°N, 102°E - 122°E) received greater influence from COVID-19. Overall NOx emission from East China for 2020 first quarter is 40.5% lower than 2019, and in P4 it is still 22.9% below the same period in 2019. The 40.5% decrease of NOx emission in 2020 first quarter in East China lead to 36.5% increase of surface O3 and 12.5% decrease of surface PM2.5. The elevated O3 promotes the secondary aerosol formation through heterogeneous pathways. We recommend that the complicated interaction between PM2.5 and O3 should be considered in the emission control strategy making process in the future.Global warming and nitrogen (N) deposition are known to affect root dynamics in grasslands. However, previous studies were based only on a single ecosystem type, so it is unclear how warming and N addition affect root traits (root biomass, root-shoot ratio, root production and turnover) along the aridity gradient. Bortezomib mouse In this study, we conducted an experiment to determine the effects of warming and N addition on root traits in desert, typical, and meadow grasslands in northern China, where the aridity gradually decreases from west to east across the region. Warming increased root-shoot ratio in dry year due to decline in soil water, but had a downward trend in root production and turnover in all three grasslands. N addition decreased root-shoot ratio in humid year due to increase in soil N, whereas did not significantly affect root production in any grasslands and increased root turnover in desert and meadow grasslands rather than typical grassland. Warming combined with N addition had negatively additive effects on root turnover in typical and meadow grasslands rather than desert grassland. N addition-induced changes in root biomass and root-shoot ratio were negatively affected by aridity in dry year. Aridity positively affected responses of root production and turnover to warming but negatively affected those responses to N addition. However, root-shoot ratio, root production and turnover under warming combined with N addition were not affected by aridity. Our results suggest that warming suppresses root carbon (C) input but N addition may exacerbate it in temperate grasslands, and warming combined with N addition suppresses it only in wet grasslands. Aridity promotes root C input under warming but suppresses it under N addition. However, aridity may little affect soil C and nutrient dynamics under global warming combined with N deposition in temperate grasslands in the future.Simulation studies following OECD guideline 309 (Aerobic Mineralisation in Surface Water - Simulation Biodegradation Test) are performed to determine the biodegradation of chemicals in surface water. The aim of our study was to perform different versions of this test to identify possible shortcomings. In order to investigate the influence of a chemical charge on the degradation, we used 14C-labelled 4-n-dodecylbenzenesulfonic acid sodium salt (14C-DS-), 4-n-dodecylbenzyltrimethylammonium chloride (14C-DA+) and 4-n-dodecylphenol (14C-DP) Additionally, abiotic degradation of these compounds and the effectiveness of different sterilization methods was assessed. The sampling technique of withdrawing sub-samples provided insufficient recoveries for 14C-DS- and 14C-DP which were mainly below 80% of applied radioactivity (AR). Therefore, the suspended sediment test was repeated using 14C-DS-, 14C-DA+ and 14C-DP and whole flasks were harvested at each sampling time resulting in superior recoveries. For 14C-DS- and 14C-DP, mineralisation was the major route of dissipation with 14CO2 evolution of 75.3% and 69.0% AR, respectively, after 62 days. Mineralisation of 14C-DA+ accounted for only 6.7% AR. Non-extractable residues (NER) of all compounds were similar after 62 days (7.3% - 9.2% AR). Sterile test conditions were best achieved using γ-irradiated sediment and autoclaved water treated with sodium azide. Under sterile conditions, mineralisation of the test compounds as well as NER formation of 14C-DS- and 14C-DP were negligible, whereas small amounts of NER were formed for 14C-DA+ (5.5% AR). We showed that OECD guideline 309 provides too much scope for the experimental setup which affects the outcome of the test and thus, needs further refinement.This study explored the effects of adding phosphogypsum (PPG), medical stone (MS), and both (PPM) during composting on nitrogen transformation, nitrogen functional genes, the bacterial community, and their relationships with NH3 and N2O emissions. Adding MS and PPM reduced NH3 emissions by 25.78-68.37% and N2O emissions by 19.00-42.86%. PPG reduced NH3 emissions by 59.74% but slightly increased N2O emissions by 8.15%. MS was strongly correlated with the amoA-dominated nitrification process. PPG and PPM had strong correlations with nirS- and nirK-dominated, and nosZ-dominated denitrification processes, respectively. PPM promoted nitrification and denitrification processes more than PPG and MS. Different functional bacteria had key roles in nitrification and denitrification during different composting stages. Firmicutes probably contributed to the conversion and release of nitrogen in the thermophilic period, whereas Proteobacteria, Chloroflexi, Bacteroidetes, and other phyla might have played important roles in the cooling and maturation periods. PPM obtained the greatest reductions in NH3 and N2O release via the regulation of environmental variables, nitrogen functional genes, and the bacterial community. Overall, these results provide insights at a molecular level into the effects of PPG and MS on nitrogen transformation and NH3 and N2O emissions during composting.