基于入户称重调研的居民春节食物消费和浪费特征

节庆期间食物消费是中国居民食物消费的重要组成,但目前缺乏对其特征结构的精准刻画。本文利用大学生网络,于2018年春节期间实地入户称重调研,获得连续3天192户1728餐居民家庭食物消费的一手数据,定量分析居民春节期间食物消费与浪费的结构和特征。研究结果表明：（1）春节期间,人均食物消费量为541.05 g/(人·餐),浪费量为30.72 g/(人·餐),浪费率为5.68%,高于非节庆时期3个百分点。（2）食物消费多为生鲜食品与平日不会每日购买的“奢侈品”,以蔬菜（21.73%）、肉类（17.77%）、大米（12.45%）、水果（8.39%）和水产类（7.88%）为主。食物浪费结构与食物消费结构相似,以蔬菜（26.20%）、肉类（21.58%）、大米（16.34%）、水产类（11.78%）和酒水（8.43%）为主。（3）春节期间,不同人口规模的家庭食物消费水平差异显著,城乡家庭、不同收入及不同人口规模的家庭食物浪费水平具有显著差异。农村家庭人均食物消费量和浪费量均高于城市家庭;经济水平高和人口规模小的家庭食物消费和浪费量更高。研究结果定量刻画了中国居民春节期间的食物消费特征,为中国《中华人民共和国反食品浪费法》中食物浪费的监测评估提供数据支撑,具有重要借鉴意义。     

碳市场对能源结构低碳转型的影响及作用路径

选取中国2000~2018年30个省市的面板数据,构建了能源消费结构低碳化指数,基于多期双重差分、三重差分等方法实证检验碳交易政策与能源消费结构低碳转型之间的关系及异质性影响,并进一步利用多重中介效应模型探讨碳交易政策推动地区能源消费结构低碳转型的作用路径.结果表明:碳交易政策可以显著提升地区能源消费结构低碳化水平且作用效果逐年增强.从作用路径看,“四大效应”激励作用彰显,作用效果由大到小依次为结构优化效应、行为驱动效应、生态创新效应和环保支出效应;从异质性影响看,GDP增速较慢地区的政策实施加快了能源消费结构低碳转型,影响明显高于GDP增速较快地区;碳交易政策对东部地区的正向推动效应显著,对中西部地区无明显促进作用.     

“双碳”背景下中国能源消费碳排放与植被固碳的时空分异

为理解中国能源消费碳排放(ERCE)与植被固碳(VCS)的演变特征及空间差异,基于气象数据、遥感数据、土地覆盖数据及统计资料等,分别在全国尺度、省域尺度和县域尺度上,定量分析2000~2017年我国ERCE和VCS的动态变化与空间分异格局,并利用碳压力指数(CPI),表征二者之间的相互关系.结果表明:(1)我国ERCE和人均ERCE在2000~2017年间表现出显著增加趋势(P<0.01),但二者分别在2013年和2012年以后出现小幅下降;空间上,二者呈现出“北高南低、东高西低”的差异特征;(2)VCS和人均VCS均在2010年以后呈现快速增加趋势(P<0.01),幅度分别为148.09×10⁶t/a和0.04t/(人·a),东北、西南和黄土高原等区域VCS和人均VCS的增加幅度明显高于其他地区;(3)全国约有近1/3的省份CPI多年平均值在1以上(即ERCE高于VCS),其中上海、天津、江苏、山东、宁夏的CPI平均值较高,且增幅也相对较大,反映出这些区域具有较大的减排压力.研究结果可为我国不同区域碳减排政策的制定提供科学依据.     

Machine learning and theoretical analysis release the non-linear relationship among ozone, secondary organic aerosol and volatile organic compounds

Fine particulate matter (PM_2.5) and ozone (O₃) pollutions are prevalent air quality issues in China. Volatile organic compounds (VOCs) have significant impact on the formation of O₃ and secondary organic aerosols (SOA) contributing PM_2.5. Herein, we investigated 54 VOCs, O₃ and SOA in Tianjin from June 2017 to May 2019 to explore the non-linear relationship among O₃, SOA and VOCs. The monthly patterns of VOCs and SOA concentrations were characterized by peak values during October to March and reached a minimum from April to September, but the observed O₃ was exactly the opposite. Machine learning methods resolved the importance of individual VOCs on O₃ and SOA that alkenes (mainly ethylene, propylene, and isoprene) have the highest importance to O₃ formation; alkanes (C_n, n ≥ 6) and aromatics were the main source of SOA formation. Machine learning methods revealed and emphasized the importance of photochemical consumptions of VOCs to O₃ and SOA formation. Ozone formation potential (OFP) and secondary organic aerosol formation potential (SOAFP) calculated by consumed VOCs quantitatively indicated that more than 80% of the consumed VOCs were alkenes which dominated the O₃ formation, and the importance of consumed aromatics and alkenes to SOAFP were 40.84% and 56.65%, respectively. Therein, isoprene contributed the most to OFP at 41.45% regardless of the season, while aromatics (58.27%) contributed the most to SOAFP in winter. Collectively, our findings can provide scientific evidence on policymaking for VOCs controls on seasonal scales to achieve effective reduction in both SOA and O₃.     

基于生命周期分析方法的家庭消费生态影响评价

建立了基于生命周期分析方法的可持续消费评价模型,并对2 0 0 0年中国城市家庭消费行为的生态影响进行了分析,比较了不同消费行为对生态影响的贡献。结果发现,2 0 0 0年中国城市家庭消费的生态影响主要来自与交通相关的消费行为,其次是食品和居住消费     

新时代循环经济发展助力美丽中国建设的路径与方向

世界主要经济体普遍把发展循环经济作为破解资源环境约束、应对气候变化、培育经济新增长点的基本路径。发展循环经济是推进生态优先、节约集约、发展方式绿色转型的必要途径,也是推进美丽中国建设的必然要求。本文从全球视野分析了物质资源消耗与经济社会发展的关系,提出了发展循环经济的战略价值,结合新时代背景阐释了循环经济发展的新内涵及其助推碳减排的关键路径。同时,分析了当前循环经济发展存在的问题,从完善循环经济评价体系、构建循环经济治理路径的实施方案、推动政用产学研融合技术创新体系、加强立法及配套政策的可操作性和完善智慧平台建设等方面提出了若干建议。     

Continuing the building's cycles: A literature review and analysis of current systems theories in comparison with the theory of Cradle to Cradle

Recently, the Cradle to Cradle (C2C) theory set ground in the Netherlands, propounding that environmental impact reduction can provide a positive economical impulse to stakeholders. The building industry has warmly received this approach and considers it to be a solution to the above-mentioned burden.However, if the building sector wants to implement C2C into their practice, a paradigm shift is required. Therefore, the sector must overcome the many difficulties it encounters while striving for an eco-effective built environment.Current sustainability strategies focus on reducing the negative environmental impact of buildings. The systems theory of C2C however aims at a positive impact; this could suggest that the state-of-the-art becomes inadequate when adopting C2C as a strategy for improvement.This paper reviews contemporary systems theories and analyses them in the light of C2C, focusing on closed or continuous materials cycles. The paper finalises by describing the hiatus in and correspondence between these current theories and C2C theory.From the study we found that C2C provides new features that help continue materials, energy and water cycles, just as the contemporary theories provide potentially useful additional material for C2C. Moreover, it reveals a striking difference between the state-of-the-art and C2C.     

The energy,water, and air pollution implications of tapping China's shale gas reserves

China has laid out an ambitious strategy for developing its vast shale gas reserves. This study developed an input–output based hybrid life-cycle inventory model to estimate the energy use, water consumption, and air emissions implications of shale gas infrastructure development in China over the period 2013–2020, including well drilling and operation, land rig and fracturing fleet manufacture, and pipeline construction. Multiple scenarios were analyzed based on different combinations of well development rates, well productivities, and success rates. Results suggest that 700–5100 petajoules (PJ) of primary energy will be required for shale gas infrastructure development, while the net primary energy yield of shale gas production over 2013–2020 was estimated at 1650–7150 PJ, suggesting a favorable energy balance. Associated emissions of CO₂e were estimated at 80–580 million metric tons, and were primarily attributable to coal-fired electricity generation, fugitive methane, and flaring of methane during shale gas processing and transmission. Direct water consumption was estimated at 20–720 million metric tons. The largest sources of energy use and emissions for infrastructure development were the metals, mining, non-metal mineral products, and power sectors, which should be the focus of energy efficiency initiatives to reduce the impacts of shale gas infrastructure development moving forward.     

基于情景分析法的中国馆碳减排效益评估

建筑部门的低碳发展已成为推进我国低碳经济至关重要的一个组成部分,因此正确客观地评价建筑的低碳水平具有重要的指导意义。本文以2010年上海世博会中国馆为研究对象,采用碳排放情景分析法,针对中国馆的基准建筑与实际建筑,计算其世博结束后正常运行条件下的碳排放水平,评估中国馆实际建筑的碳减排效益。使用建筑能耗模拟软件DesignBuilder对建筑全年能源消耗水平进行了模拟,并通过相应能源品种的碳排放因子分别计算了实际建筑和基准建筑的碳排放水平;同时应用全生命周期方法(LCA)分析了中国馆实际建筑应用太阳能光伏、LED照明技术相比于基准建筑所带来的减排效益。结果表明:世博结束后正常运行条件下,中国馆实际建筑年碳排放量为18 969 t CO2e,基准建筑年碳排放量为25 770 t CO2e,因此,相比基准建筑,中国馆实际建筑一年减排6 801 t CO2e,年碳减排率为26.4%;减排效益主要由节能设计及绿色技术贡献,分别占96.3%和3.7%。本文通过综合评估中国馆的碳减排效益,以期为我国公共建筑低碳工作的开展进行有益的探索。     

山东省城市化和能源消耗的关系研究

通过建立向量自回归模型,运用格兰杰因果分析方法和协整分析方法对于山东省城市化和能源消耗量之间的长短期关系进行了实证分析,并利用因素分解模型对城市化所引起的能源消耗变动的贡献份额进行了定量测算。实证结果表明,山东省城市化水平提高是导致能源消费量增长的格兰杰因果原因,而山东省能源消费增长却不是城市化水平提高的格兰杰因果原因,二者之间存在单向的格兰杰因果联系。山东省城市化和能源消耗量之间不仅存在着单向的格兰杰因果联系,并且存在着协整关系,但是这种长期动态均衡的短期误差修正作用并不很强,能源消耗量的增长率变动除了受城市化水平影响之外,还同时受到其他多种因素的影响;现阶段城市化因素对山东省能源消费总量的贡献份额尚比较小,且有逐年下降的趋势。因此,能源需求不会成为制约山东省城市化进程的瓶颈,目前应该加快推进有助于资源节约型的城市化进程模式。