Generic spatial classes for human health impacts, part II:

Within a Life Cycle Assessment of the fuel supply and the operation of cars fueled by natural gas, diesel and gasoline, the impacts of airborne pollutants on human health were assessed in a spatially differentiated way. Country average impacts were used for secondary sulfate and nitrate aerosols. The use of country average impacts also turned out to be sufficient for the primary pollutants emitted from most processes of the fuel supply. For emissions of primary pollutants from the vehicles and from some processes of the fuel supply, the low to moderate emission height and the high local population density in urban areas needed to be taken into account. In these cases, the method of generic spatial classes presented in Part I was applied. The spatially differentiated impacts were compared with the results of a generic impact assessment based on average European damage factors. The generic impact assessment overestimates the human health impact of the fuel supply by about a factor of 2, since many of the upstream processes take place in very sparsely populated countries, and underestimates the impact of the primary particles emitted by the diesel cars in large cities by about a factor of 2.     

中国典型城市群城镇化碳排放驱动因子

城市群作为推进国家新型城镇化的战略举措,是国家参与全球竞争与国际分工的主要地域单元。以中国典型城市群6个代表性城市(北京、天津、上海、广州、武汉和重庆)为案例,采用因素分解法将碳排放的影响效应分解为4部分,包括人口规模效应、经济发展效应、能源强度效应和碳强度效应,研究2000—2014年城镇化过程中碳排放的驱动机制。主要结果:(1)各城市群的经济总量均有增长,能源效率逐渐提高,碳排放强度在北京、上海和重庆的是下降趋势,在天津呈上升趋势,而在广州和武汉则趋于平稳状态,各城市群能源消耗中各种能源的比重和碳排放量的变化存在着较显著的差异性;(2)天津和广州的4个碳排放影响效应整体上是逐渐增大,北京和上海是趋于平稳对称,武汉和重庆是先减小后增大。研究表明,经济和人口对碳排放具有正向作用,能源强度对碳排放具有负向作用。通过研究中国典型城市群碳排放的驱动因子,有助于城市群碳排放权交易的政策制定以及城市群发展模式规划。     

华北平原土地利用/覆盖对CO空间分布的调控作用

CO不仅是中国主要的空气污染物之一,还是温室效应的贡献者。农业用地每年消耗了大量的CO通量,土地利用/覆盖格局对于调控CO空间分布发挥了较大的作用。针对土地利用/覆盖调控CO空间分布开展研究,以华北平原为例揭示人类活动对CO空间异质性的影响。研究发现2010至2020年华北平原CO排放量由4964×10⁴ t降低至2683×10⁴ t,大部分耕地CO浓度由90 t/km²下降至45 t/km²以下。CO浓度空间集聚程度呈现先降低后升高趋势,Moran′s I指数由0.25增加至0.41。经济发展迅速的地区CO污染较为严重,北京和周边城市形成了CO污染高-高集聚区,周口和淮北等城市则形成了低-低集聚区。总体来看,CO浓度呈低-低集聚分布的区域不断扩大,反映出CO减排措施已经初见效果。研究表明土地利用/覆盖在类型与结构方面的差异影响了CO的排放、扩散以及氧化消耗,增加了大气CO收支的不确定性,对CO空间分布具有一定的调控作用。通过分析土地利用/覆盖与CO空间分布的关联性,探究土地利用/覆盖及景观格局对区...     

A characterization model with spatial and temporal resolution for life cycle impact assessment of photochemical precursors in the United States

Background, aim, and scope  Traditional life cycle impact assessment methodologies have used aggregated characterization factors, neglecting spatial and temporal variations in regional impacts like photochemical oxidant formation. This increases the uncertainty of the LCA results and diminishes the ease of decision-making. This study compares four common impact assessment methods, CML2001, Eco-indicator 99, TRACI, and EDIP2003, on their underlying models, spatial and temporal resolution, and the level at which photochemical oxidant impacts are calculated. A new characterization model is proposed that incorporates spatial and temporal differentiation. Materials and methods  A photochemical air quality modeling system (CAMx-MM5-SMOKE) is used to simulate the process of formation, transformation, transport, and removal of photochemical pollutants. Monthly characterization factors for individual US states are calculated at three levels along the cause–effect chain, namely, fate level, human and ecosystem exposure level, and human effect level. Results and discussion  The results indicate that a spatial variability of one order of magnitude and a temporal variability of two orders of magnitude exist in both the fate level and human exposure and effect level characterization factors for NO_x. The summer time characterization factors for NO_x are higher than the winter time factors. However, for anthropogenic VOC, the summer time factors are lower than the winter time in almost half of the states. This is due to the higher emission rates of biogenic VOCs in the summer. The ecosystem exposure factors for NO_x and VOC do not follow a regular pattern and show a spatial variation of about three orders of magnitude. They do not show strong correlation with the human exposure factors. Sensitivity analysis has shown that the effect of meteorology and emission inputs is limited to a factor of three, which is several times smaller than the variation seen in the factors. Conclusions  Uncertainties are introduced in the characterization of photochemical precursors due to a failure to consider the spatial and temporal variations. Seasonal variations in photochemical activity influence the characterization factors more than the location of emissions. The human and ecosystem exposures occur through different mechanisms, and impacts calculated at the fate level based only on ozone concentration are not a good indicator for ecosystem impacts. Recommendations and perspectives  Spatial and temporal differentiation account for fate and transport of the pollutant, and the exposure of and effect on the sensitive human population or ecosystem. Adequate resolution for seasonal and regional processes, like photochemical oxidant formation, is important to reduce the uncertainty in impact assessment and improve decision-making power. An emphasis on incorporating some form of spatial and temporal information within standard LCI databases and using adequately resolved characterization factors will greatly increase the fidelity of a standard LCA. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

LCA of Multicrystalline Silicon Photovoltaic Systems - Part 1: Present Situation and Future Perspectives (8 pp)

- Part 1: Present Situation and Future Perspectives Part 2: Application on an Island Economy Goal, Scope and Background Incorporation of exposure and risk concepts into life cycle impact assessment (LCIA) is often impaired by the number of sources and the complexity of site-specific impact assessment, especially when input-output (I-O) analysis is used to evaluate upstream processes. This makes it difficult to interpret LCIA outputs, especially in policy contexts. In this study, we develop an LCIA tool which takes into account the geographical variability in both emissions and exposure, and which can be applied to all economic sectors in I-O analysis. Our method relies on screening-level risk calculations and methods to estimate population exposure per unit of emissions from specific geographic locations. Methods We propose a simplified impact assessment approach using the concept of intake fraction, which is the fraction of a pollutant or its precursor emitted that is eventually inhaled or ingested by the population. Instead of running a complex site-specific exposure analysis, intake fractions allow for the accounting of the regional variability in exposure due to meteorological factors and population density without much computational burden. We calculate sector-specific intake fractions using previously-derived regression models and apply these values to the supply chain emissions to screen for the sectors whose emissions largely contribute to the total exposures. Thus, the analytical steps are simplified by relying on these screening-level risk calculations. We estimate population exposure per unit emissions from specific geographic locations only for the facilities and pollutants that pass an initial screening analysis. We test our analytical approach with reference to the case of increasing insulation for new single-family homes in the US. We quantify the public health costs from increasing insulation manufacturing and compare them with the benefits from energy savings, focusing on mortality and morbidity associated with exposure to primary and secondary fine particles (PM2.5) as well as cancer risk associated with exposure to toxic air pollutants. We estimate health impacts using concentration-response functions from the published literature and compare the costs and benefits of the program by assigning monetary values to the health risks. In the second part of this paper, we present the results of our case study and consider the implications for incorporating exposure and risk concepts into I-O LCA. Conclusions We have presented a methodology to incorporate regional variability in emissions and exposure into input-output LCA, using reduced-form information about the relationship between emissions and population exposure, along with standard input-output analysis and risk assessment methods. The location-weighted intake fractions can overcome the difficulty in incorporation of regional exposure in LCIA.     

浙江三大城市群绿色发展效率时空分异及影响机理

提升浙江三大城市群绿色发展效率是浙江加快建成美丽中国先行示范区的重要途径之一.以三大城市群包含的41个县(市)为依托,以2000-2019年县域面板数据为样本,将超效率SBM模型与窗口分析及测度效率相结合,运用空间计量分析方法研究效率的空间分布及区域差异,并借助面板固定效应模型探索效率的差异化影响机理.结果 表明:研究...     

城市街谷大气污染物分布研究进展

城市街谷是现代城市最重要的空间形式与特征之一,是城市中使用频率最高、汽车尾气污染最严重、日常人口密度最大的公共空间类型之一。城市街谷不合理的空间配置和结构会造成城市通风自净能力降低,大气污染物浓度增高。本文综述了城市街谷形态、行道树配置、机动车车流量和气象因素等对街谷大气污染物分布的影响,以及数值模拟、风洞试验和实地监测等用于街谷大气污染物分布及扩散研究的相关方法。建议未来以实地监测数据为基础,综合考虑多种因素对街谷大气污染物分布的研究,提出适宜城市大气污染物扩散的城市街谷构建模式,从城市规划和格局优化的角度为城市大气污染物的减控提出科学支撑和优化方案。     

A Risk-Based Approach to Health Impact Assessment for Input-Output Analysis, Part 1: Methodology (7 pp)

Goal, Scope and Background Incorporation of exposure and risk concepts into life cycle impact assessment (LCIA) is often impaired by the number of sources and the complexity of site-specific impact assessment, especially when input-output (I-O) analysis is used to evaluate upstream processes. This makes it difficult to interpret LCIA outputs, especially in policy contexts. In this study, we develop an LCIA tool which takes into account the geographical variability in both emissions and exposure and which can be applied to all economic sectors in I-O analysis, relying on screening-level risk calculations and methods to estimate population exposure per unit emissions from specific geographic locations. Methods We develop our analytical approach with reference to the case of increasing insulation for new single-family homes in the US. We quantify the public health costs from increasing insulation manufacturing and compare them with the benefits from energy savings, focusing on mortality and morbidity associated with exposure to primary and secondary fine particles (PM2.5) as well as cancer risk associated with exposure to toxic air pollutants. We use OpenLC to estimate the incremental economic outputs induced by increased insulation and reduced fuel consumption and calculate emissions from a sector-specific pollution intensity matrix. We calculate sector-specific intake fractions (dimensionless ratios between the amount of pollutant intake and the amount of a pollutant emitted) using previously-derived regression models and apply these values to the supply chain emissions of fiberglass and fuel sources. We refine the exposure estimates for selected emission sites and pollutants that contribute significantly to total health impacts, running site-specific air dispersion models. We estimate health impacts using concentration-response functions from the published literature and compare the costs and benefits of the program by assigning monetary values to the health risks. In the second part of this paper, we present the results of our case study and consider the implications for incorporating exposure and risk concepts into I-O LCA.     

Spatial greenhouse gas emissions from US county corn production

Purpose

Stakeholders from across supply chains have been prompted to explore ways to reduce the environmental burdens of corn production. To effectively manage these environmental impacts, spatially explicit information accounting for the differences in growing conditions and production practices across the production landscape is essential, allowing for high impact intensity corn to be identified and prioritized for improvement. To support these sustainability efforts, this study examines the spatially explicit life cycle greenhouse gas emissions of US county corn production, providing the most comprehensive assessment to date.

Methods

A streamlined spatial life cycle assessment is conducted, focusing on the three key hotspots of corn production for spatial differentiation at the county scale across the contiguous USA, accounting for almost 60% of total average cradle-to-farm gate impacts. Variations in nitrogen fertilization types and rates, N₂O emission rates, and irrigation emission rates are specifically revealed. Spatially distinguished hotspot inputs and related emissions are combined with static national average emission estimates from all other inputs used in corn production to gain a full picture and understand the relative contributions to total cradle-to gate impacts.

Results and discussion

Results show significant variation across corn producing counties, states, and regions. High impact priority locations are highlighted and key contributors of impact for each location are illuminated, providing critical information on the spatially explicit levers to reduce impacts. Results increase the generalizability of emission estimates using expected yields to characterize emission intensity, enabling more practical integration into company supply chain sustainability assessments to align with the time horizons in which decisions are made.

Conclusions

Streamlined life cycle assessment methods are an effective way to characterize spatial heterogeneity around key contributors of impact, helping deliver the necessary information for companies, stakeholders, and policy makers to target their influence to reduce these emissions through various engagement efforts.

     

Human Health Damages due to Indoor Sources of Organic Compounds and Radioactivity in Life Cycle Impact Assessment of Dwellings - Part 2: Damage Scores (10 pp)

- Part 1: Characterisation factors (DOI: http://dx.doi.org/10.1065/lca2004.12.194.1) Part 2: Damage scores (DOI: http://dx.doi.org/10.1065/lca2004.12.194.2) - Preamble. In this series of two papers, a methodology to calculate damages to human health caused by indoor emissions from building materials is presented and applied. Part 1 presents the theoretical foundation of the indoor emission methodology developed, as well as characterisation factors calculated for 36 organic compounds, radon and gamma radiation. Part 2 calculates damage scores of building materials with the characterisation factors presented in part 1. The relevancy of including indoor air emission in the full damage scores at a material level and a dwelling level is also quantified and discussed. Goal, Scope and Background In industrialized countries such as the Netherlands, the concentration of pollutants originating from building materials in the indoor environment has shown an increasing trend during the last decades due to improved isolation and decreased ventilation of dwellings. These pollutants may give rise to negative impacts on human health, ranging from irritation to tumours. However, such negative impacts on health are not included in current life cycle assessments of dwellings. In this study, damages to the health of occupants caused by a number of organic compounds and by radioactivity emitted by building materials, including those due to indoor exposure, have been calculated for a number of categories of common building materials. The total damage to human health due to emissions occurring in the use phase of the Dutch reference dwelling is compared with the total damage to human health associated with the rest of the life cycle of the same dwelling. Methods Human health damage scores per kilogram of building material for compartments of the Dutch reference dwelling have been calculated using the methodology described in part I of this research. This methodology includes the calculation of the fate, effect and damage factors, based on disability adjusted life years (DALYs), and has been applied assuming average concentrations of pollutants in building materials. Damage scores for health impacts of exposure to pollutants emitted during the production and the disposal phase of the same building materials were calculated using standard LCIA methodology. Results and Discussion Human health damage scores due to emissions of pollutants occurring in the use phase of building materials applied at the first or second floor are up to 20 times lower or higher than the corresponding damage scores associated with the rest of the life cycle of the same building materials. The damage scores due to emissions occurring in the use phase of building materials applied in the crawlspace are up to 105 times lower than those of building materials applied in the other compartments. The total damage to human health due to emissions occurring in the use phase of the Dutch reference dwelling has the same order of magnitude as the total damage to human health associated with the rest of the life cycle of the same dwelling. At a dwelling level, radon and gamma radiation are dominant in the human health damage score among the pollutants studied. Conclusion Health damages due to indoor exposure to contaminants emitted by building materials cannot be neglected for several materials when compared with damage scores associated with the rest of the life cycle of the same building materials. Indoor exposure to pollutants emitted by building materials should be included in the life cycle assessment of dwellings in order to make the assessment better reflect full impact of the life cycle.     

基于DMSP/OLS影像的我国主要城市群空间扩张特征分析

20世纪90年代以来,随着中国城市化步伐的加快,城市用地空间扩张极为明显。采用1992、1995、2000、2005、2009年5期的夜间灯光影像数据提取了京津冀、长江三角洲和珠江三角洲城市群的城市像元,并从空间扩张强度、扩张类型以及方向性空间扩张特征3个方面对三大城市群城市用地的空间扩张特征进行了分析,同时还从社会经济方面对城市群空间扩张的驱动因素进行了讨论。结果表明,三大城市群的空间扩张特征既存在共性也存在明显的差异,同时社会经济的快速发展对城市用地的扩张具有明显的驱动作用,为进一步推动中国城市化进程提供了数据支撑。     

海岛碳排放核算与时空特征——以东山岛为例

把握地区碳信息发展动态是开展区域碳平衡规划的科学基础。以统计年鉴数据为基础,对东山岛2012—2021年整体及各产业的直接碳排放量进行核算,同时,将产业与土地利用结合,分析其空间表现形态,运用核密度分析和克里金法分析碳排放源的空间影响,采用高斯烟羽模型对工业点源的碳排放扩散进行空间模拟,通过渔网和人口修正的方法分析海岛碳排放的空间分异,以此探讨海岛碳排放的空间分布和空间影响特征。结果显示,工业是东山岛的首要碳排放源,2021年工业碳排放量的大幅下降表明能源种类的转换对于工业碳减排具有重要作用;渔业碳排放量总体占比25%左右,是海岛地区不容忽视的碳排放源之一。在空间分布方面,东山岛综合碳排放的空间分布呈“点状聚集,面状扩散”的基本特征,工业碳排放对周围地区的影响最大,往往形成以工业碳排放源点为中心的碳排放热点核心区,其次碳排放量较高的地区为人口聚集区,丘陵区的碳排放量最低,不同土地利用类型之间形成碳排放的交叉过渡区。最后,本文从碳排放空间影响的视角出发,根据不同形态的碳排放源提出“包围”、“伴随”和“介入”的碳汇空间规划策略,这对区域的低碳规划具有一定参考意义。     

基于夜间灯光数据的湖南省县域碳排放时空格局及影响因素研究

研究碳排放的时空格局演变及影响因素对指导制定差异化的碳减排政策具有重要意义。基于夜间灯光数据,在估算湖南省各县区碳排放量的基础上,结合空间统计、空间自相关、热点分析、地理加权回归、GIS等方法研究了湖南省县域碳排放的空间分异、时空格局特征与影响因素。研究结果表明:(1)2013—2017年,湖南省能源消费碳排放总体上呈现东高西低的空间格局,碳排放主要集中于区域的市辖区,县域碳排放最高点在长沙市市辖区;(2)湖南省能源消费碳排放存在较为显著的空间正相关,全省县域尺度能源消费碳排放全局Moran’sI指数整体呈现出逐年上升的趋势,各市的市辖区在中心相互辐射,表现出显著的集聚现象,并形成了碳排放“高-高型”分布特征;(3)湖南省能源消费碳排放量的冷热点格局表现出湘南地区冷点扩张,湘中地区热点扩张的演变趋势,从2013年到2017年,热点区与次热点区由11个升至13个,湘中地区与其他地区的冷热点差距在逐步拉大;(4)影响湖南省县域能源消费碳排放量的4个影响因素与碳排放均表现为正相关性,其影响程度依次为人口、人均GDP、第二产业比重与单位GDP能耗。     

Uncertainty and spatial variability in characterization factors for aquatic acidification at the global scale

Purpose

Characterization factors (CFs) quantifying the potential impact of acidifying emissions on inland aquatic environments in life cycle assessment are typically available on a generic level. The lack of spatial differentiation may weaken the relevance of generic CFs since it was shown that regional impact categories such as aquatic acidification were influenced by the surroundings of the emission location. This paper presents a novel approach for the development of spatially differentiated CFs at a global scale for the aquatic acidification impact category.

Methods

CFs were defined as the change in relative decrease of lake fish species richness due to a change in acidifying chemicals emissions. The characterization model includes the modelling steps linking emission to atmospheric acid deposition (atmospheric fate factor) change, which lead to lake H⁺ concentration (receiving environment fate factor) change and a decrease in relative fish species richness (effect factor). We also evaluated the significance of each factor (i.e. atmospheric fate, receiving environment fate and effects) to the overall CFs spatial variability and parameter uncertainty.

Results and discussion

The highest CFs were found for emissions occurring in Canada, Scandinavia and the northern central Asia because of the extensive lake areas in these regions (lake areas being one of the parameters of the CFs; the bigger the lake areas, the higher the CFs). The CFs’ spatial variability ranged over 5, 6 and 8 orders of magnitude for NO_x, SO₂ and NH₃ emissions, respectively. We found that the aquatic receiving environment fate factor is the dominant contributor to the overall spatial variability of the CFs, while the effect factors contributed to 98 % of the total parameter uncertainty.

Conclusions

The resulting characterization model and factors enable a consistent evaluation of spatially explicit acidifying emissions impacts at the global scale.     

Estimates of real damage from air pollution: Site dependence and simple impact indices for LCA

In contrast to the various “potential impact” indices that have been proposed, we show that indices for real damage can be derived, based on the impact pathway methodology which involves the calculation of increased pollutant concentration in all affected regions due to an incremental emission (e.g. μg/m³ of particles, using models of atmospheric dispersion and chemistry), followed by the calculation of physical impacts (e.g. number of cases of asthma due to these particles, using a concentration-response function). The numbers are summed over all receptors of concern (population, crops, buildings,…). We show that in a uniform world (linear dose-response function, uniform receptor density and uniform atmospheric removal rate) the conservation of matter implies a very simple formula for the total damage. The generalization to secondary pollutants is straightforward. By detailed numerical evaluations, using real data for atmospheric dispersion and geographic receptor distribution, we have demonstrated that this simple formula is an excellent representation of typical damages. Results are shown for the principal air pollutants emitted by smoke stacks of industrial installations or by road transport. A preliminary version was presented as a key note lecture at the SETAC Meeting in Bordeaux, April 14-18, 1998     

Dependence of Intake Fraction on Release Location in a Multimedia Framework

A defining feature of industrial ecology is the design of processes to minimize any disruption of the functioning of the natural ecosystem that supports life, including human beings. The extent of human exposure to anthropogenic contaminants in the environment is a complex function of the amount of chemical emitted, its physicochemical properties and reactivity, the nature of the environment, and the characteristics of the pathways for human exposure, such as inhalation, dermal contacts, and intake of food and water. For some chemicals, the location of emissions relative to areas of high population density or intense food production may also be an important factor. We explore the relative importance of these variables using the regionally segmented Berkeleyf-Trent (BETR) North America contaminant fate model and data for food production patterns and population density for North America. The model is applied to fourfff contaminants emitted to air: benzene, carbon tetrachloride, benzo-a-pyrene, and 2,3,7,8 tetrachlorodibenzo-pff-dioxin. The total continental intake fraction (iF), relating exposure quantity to emission quantity, is employed as a metric for assessing population exposure to these contaminants. Results show that the use of continentally averaged parameters for population density and food production provides an accurate estimate of the median of iF calculated for emissions in individual regions; however, iF can range from this median by up to 3 orders of magnitude, especially for chemicals transferred to humans through foods. The locations of population and food production relative to sources of chemicals are important variables that should be considered when assessing the possible human health impacts of chemical emissions as in life-cycle assessment.     

江西县域土地利用变化碳排放时空演变及其影响因素

查明县域尺度下土地利用变化碳排放,对于推进县域低碳发展和土地资源的可持续利用与管理具有重要意义。以江西省为例,基于2000-2020年江西省土地利用数据、社会经济数据等,利用空间自相关模型和对数平均迪氏指数分解法(LMDI) 法,对其县域土地利用碳排放时空演变及影响因素进行分析。结果表明:①2000-2020年间,区县土地利用碳排放均呈上升趋势,碳排放量增速和平均碳排放强度均有下降,但部分区县碳排放增速在2015年后出现提高的变化特征。建设用地是碳排放量增长的首要碳源,林地则具有重要的碳汇作用。②空间上,土地利用变化碳排放呈现出明显的空间差异,表现为北高南低的分布特征和较为稳定的聚类模式,即轻度和重度及以上排放区空间分布上较为集中。经济发达区县成为碳排放量增长"核心",欠发达区县则是碳排放量增长"外围",且这种"核心-外围"格局在不断强化。③总体上,抑制碳排放量增长的主要因素为碳排放强度及土地利用效率;驱动因素则有经济发展水平和建设用地规模。但部分区县碳排放强度可能表现为"前期驱动后期抑制"作用,且抑制作用小于驱动作用,故这类区县土地利用碳排放量仍显著增长。因此,江西省各区县应积极调整产业结构和继续降低碳排放强度及通过优化土地资源配置,提高土地利用效率,如用适度集约模式提高建设用地利用效率以免盲目性扩张浪费。另外,欠发达地区和发达地区需加强在资金、技术等领域的交流与合作,不同区县还应因地制宜,各自明确发展目标,走具有各自县域特色的低碳高质量发展道路。     

中国城市生态基础设施对碳排放量的影响

在碳达峰、碳中和的时代背景下,探究城市生态基础设施的碳减排效应对实现城市的可持续性发展、现代化发展具有重要的现实意义。选用中国2003-2019年中国214个地级市为样本,采用熵权法量化中国城市生态基础设施发展水平,构建空间计量模型研究城市生态基础设施发展对碳排放量的影响及其空间溢出效应。研究发现：（1）中国城市碳排放总量整体呈上升趋势,并且碳排放量较高的地区是人口密度较大的城市,以及传统工业城市。城市生态基础设施发展水平总体呈先下降,后上升的趋势,发展较好的城市分布在东部沿海地区,西北城市,中部省会与直辖市。（2）城市生态基础设施发展显著促进了本地城市和邻地城市的碳排放量,该结果通过稳健性检验。并且,城市生态基础设施的碳减排效应存在滞后性,城市生态基础设施在发展至12期时,具有显著的碳减排效应。（3）城市第二产业发展具有集聚效应,降低了邻地城市的碳排放量;城市对外开放程度越高,地区间贸易加速流动,促进了邻地城市的碳排放量。（4）与其他城市相比,西部地区城市、非省会城市和直辖市,以及资源型城市的生态基础设施发展显著促进了城市碳排放。（5）政策制定上,一方面应全力推进城市生态基础设施发展和第二产业转型,重视城市绿化覆盖、垃圾废水处理等设施建设。另一方面需特别关注西部地区城市、非直辖市和非省会城市、以及资源型城市,因地制宜,激发其生态基础设施建设动力,助推碳达峰、碳中和目标的实现。     

A spatial analysis of atmospheric ammonia and ammonium in the U.K

As measures are implemented internationally to reduce SO2 and NOx emissions, attention is falling on the contribution of NH3 emissions to acidification, nitrogen eutrophication, and aerosol formation. In the U.K., a monitoring network has been established to measure the spatial distribution and long-term trends in atmospheric gaseous NH3 and aerosol NH4+. At the same time, an atmospheric chemistry and transport model, FRAME, has been developed with a focus on reduced nitrogen (NHx). The monitoring data are important to evaluate the model, while the model is essential for a more detailed spatial assessment. The national network is established with over 80 sampling locations. Measurements of NH3 and NH4+ (at up to 50 sites) have been made using a new low-cost denuder-filterpack system. Additionally, improved passive sampling methods for NH3 have been applied to explore local variability. The measurements confirm the high spatial variability of NH3 (annual means 0.06 to 11 microg NH3 m(-3)), consistent with its nature as a primary pollutant emitted from ground-level sources, while NH4+, being a slowly formed secondary product, shows much less spatial variability (0.14 to 2.4 mg NH4+ m(-3)). These features are reproduced in the FRAME model, which provides estimates at a 5-km level. Analysis of the underlying NH3 emission inventory shows that sheep emissions may have been underestimated and nonagricultural sources overestimated relative to emissions from cattle. The combination of model and measurements is applied to estimate spatial patterns of dry deposition to different vegetation types. The combined approach provides the basis to assess NHx responses across the U.K. to international emission controls.     

城市三维空间结构对碳排放影响的尺度效应

城市是碳排放最集中的区域,全面厘清城市空间结构对碳排放的影响对碳减排规划具有重要意义。以往研究主要关注城市二维结构与碳排放的关系,表明城市扩张是碳排放剧增的主要原因。虽然城市三维空间结构也会显著影响碳排放,然而其影响的尺度效应依然缺少深入分析。为此以广州市为例,结合相关性分析、随机森林探究三维空间结构与碳排放的关系,并揭示三维空间结构影响的尺度效应。研究结果表明：（1）（高层）建筑物密度、建筑覆盖率、容积率与人口密度是碳排放的关键影响因素,主要通过直接增加人类活动或加剧热岛效应使得能源消耗和碳排放增多;（2）三维空间结构对碳排放的影响具有明显的尺度效应。随着分析尺度的变化,碳排放受三维空间结构的不同方面主导;（3）广州作为紧凑型城市的代表,如果片面追求城市三维空间的紧凑布局将不利于低碳城市的发展。因此,相关部门应重视宏观尺度下的三维空间结构的合理布局,合理开发城市边缘地区,降低城市中心建筑物的紧凑布局,构建多中心的城市格局,以有效降低碳排放水平,促进低碳城市的构建与可持续发展。研究所得成果可为城市建筑三维空间布局的合理优化提供参考依据,助力"双碳"目标的实现。