The first detailed inventory for volatile organic compounds(VOC) emissions from vegetation over Yunnan Province, China was presented. The spatially and temporally resolved inventory was developed based on a geographic...The first detailed inventory for volatile organic compounds(VOC) emissions from vegetation over Yunnan Province, China was presented. The spatially and temporally resolved inventory was developed based on a geographic information system(GIS), remote sensing(RS) data and field measurement data, such as digitized land-use data, normalized difference vegetation index(NDVI) and temperature data from direct real-time measurement. The inventory has a spatial resolution of 5 km×5 km and a time resolution of 1 h. Urban, agriculture, and natural land-use distributions in Yunnan Province were combined with biomass factors for each land-use category to produce a spatially resolved biomass inventory. A biogenic emission inventory was developed by combining the biomass inventory with hourly emission rates for tree, shrub and ground cover species of the study area. Correcting for environmental factors, including light intensity and temperature, a value of 1.1×10 12 gC for total annual biogenic VOC emissions from Yunnan Province, including 6.1×10 11 gC for isoprene, 2.1×10 11 gC for monoterpenes, and 2.6×10 11 gC for OVOC was obtained. The highest VOC emissions occurred in the northwestern, southwestern and north region of Yunnan Province. Some uncertainties were also discussed in this study.展开更多
The control strategy and simulation of external carbon addition were specially studied in an anoxic-oxic(A/O) process with low carbon: nitrogen(C/N) domestic wastewater. The control strategy aimed to adjust the flow r...The control strategy and simulation of external carbon addition were specially studied in an anoxic-oxic(A/O) process with low carbon: nitrogen(C/N) domestic wastewater. The control strategy aimed to adjust the flow rate of external carbon dosage to the anoxic zone, thus the concentration of nitrate plus nitrite(NOx--N) in the anoxic zone was kept closed to the set point. The relationship was studied between the NOx--N concentration in the anoxic zone(S_ NO) and the dosage of external carbon, and the results showed that the removal efficiency of the total nitrogen(TN) could not be largely improved by double dosage of carbon source when S_ NO reached about 2 mg/L. Through keeping S_ NO at the level of about 2 mg/L, the demand of effluent quality could be met and the carbon dosage could be optimized. Based on the Activated Sludge Model No.1(ASM No.1), a simplified mathematical model of external carbon dosage was developed. Simulation results showed that PI controller and feed-forward PI controller both had good dynamic response and steady precision. And feed-forward PI controller had better control effects due to its consideration of influent disturbances.展开更多
Twenty three kinds of typical plants in Xishuangbanna, the tropical area of southwestern China, were screened to estimate the emission rates of isoprene and monoterpenes by adopting bag enclosure and curette sampling ...Twenty three kinds of typical plants in Xishuangbanna, the tropical area of southwestern China, were screened to estimate the emission rates of isoprene and monoterpenes by adopting bag enclosure and curette sampling methods followed by a GC FID analysis. It was found that the Ficus species were mainly emitting isoprene and most tropical vegetations were mainly releasing monoterpenes. The results also showed that the emissions of isoprene were affected by both temperature and PAR(Photosynthetic Active Radiation), while monoterpene emissions were mainly temperature dependent.展开更多
基金The National Natural Science Foundation of China(No. 40075027 40375038)
文摘The first detailed inventory for volatile organic compounds(VOC) emissions from vegetation over Yunnan Province, China was presented. The spatially and temporally resolved inventory was developed based on a geographic information system(GIS), remote sensing(RS) data and field measurement data, such as digitized land-use data, normalized difference vegetation index(NDVI) and temperature data from direct real-time measurement. The inventory has a spatial resolution of 5 km×5 km and a time resolution of 1 h. Urban, agriculture, and natural land-use distributions in Yunnan Province were combined with biomass factors for each land-use category to produce a spatially resolved biomass inventory. A biogenic emission inventory was developed by combining the biomass inventory with hourly emission rates for tree, shrub and ground cover species of the study area. Correcting for environmental factors, including light intensity and temperature, a value of 1.1×10 12 gC for total annual biogenic VOC emissions from Yunnan Province, including 6.1×10 11 gC for isoprene, 2.1×10 11 gC for monoterpenes, and 2.6×10 11 gC for OVOC was obtained. The highest VOC emissions occurred in the northwestern, southwestern and north region of Yunnan Province. Some uncertainties were also discussed in this study.
基金Foundation item:Beijing Science and Technology Commission(No. H020620010120), the Significant International Projects of the National Natural Science Foundation of China(No. 50521140075), Beijing Municipal Education Commission(No. KZ200310005003) and Beijing Key Laboratories
文摘The control strategy and simulation of external carbon addition were specially studied in an anoxic-oxic(A/O) process with low carbon: nitrogen(C/N) domestic wastewater. The control strategy aimed to adjust the flow rate of external carbon dosage to the anoxic zone, thus the concentration of nitrate plus nitrite(NOx--N) in the anoxic zone was kept closed to the set point. The relationship was studied between the NOx--N concentration in the anoxic zone(S_ NO) and the dosage of external carbon, and the results showed that the removal efficiency of the total nitrogen(TN) could not be largely improved by double dosage of carbon source when S_ NO reached about 2 mg/L. Through keeping S_ NO at the level of about 2 mg/L, the demand of effluent quality could be met and the carbon dosage could be optimized. Based on the Activated Sludge Model No.1(ASM No.1), a simplified mathematical model of external carbon dosage was developed. Simulation results showed that PI controller and feed-forward PI controller both had good dynamic response and steady precision. And feed-forward PI controller had better control effects due to its consideration of influent disturbances.
文摘Twenty three kinds of typical plants in Xishuangbanna, the tropical area of southwestern China, were screened to estimate the emission rates of isoprene and monoterpenes by adopting bag enclosure and curette sampling methods followed by a GC FID analysis. It was found that the Ficus species were mainly emitting isoprene and most tropical vegetations were mainly releasing monoterpenes. The results also showed that the emissions of isoprene were affected by both temperature and PAR(Photosynthetic Active Radiation), while monoterpene emissions were mainly temperature dependent.
