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911.
保定市大气污染变化趋势及特征 总被引:2,自引:1,他引:1
为了解保定市近年来大气污染变化趋势和污染特征,对2013~2018年保定市空气质量和大气污染物浓度进行分析,结果表明:(1)从2013~2018年保定市综合指数由11.6下降到6.6,重度污染天数由114 d下降到27 d,重度污染时污染物累积浓度由57.34%下降到20.59%.表明2013~2018年保定市空气质量逐年改善,不仅重污染天数减少、污染物年均浓度降低,而且重污染时污染物累积浓度的占比也在下降,同时与"2+26"城市平均浓度水平的差距越来越小.(2)夏季ρ(O3-8h)逐年上升, 2017年和2018年由O3导致的重污染天分别占当年重污染天的17.0%和14.8%,臭氧污染逐渐突出;秋季NO2特征值高于SO2、CO、PM2.5和PM10,说明秋季污染类型偏机动车型;冬季污染类型由2013~2014年的偏燃煤型转向2015~2018年的偏燃煤型和不完全燃烧的混合影响.(3)2016、 2017和2018年高污染季PM2.5... 相似文献
912.
2003—2018年全国酸雨状况变化趋势研究 总被引:1,自引:0,他引:1
基于2003—2018年全国291个城市降水监测结果的分析表明:全国降水酸度明显降低,其中,2003—2006年有所升高,2006年之后呈降低趋势;酸雨区面积呈减小趋势,共减少约97万km2,酸雨发生频率超过5%的面积减少了20.9个百分点;全国酸雨城市比例为21.3%~40.9%,2009年开始总体呈下降趋势,2018年降为21.6%,重酸雨城市比例在2005年之后总体呈下降趋势;全国平均酸雨频率为11.7%~25.6%,2006年之后总体呈下降趋势,2018年酸雨频率在50%以上的城市比例较2006年下降了13.9个百分点。基于174个城市的降水离子组分分析结果显示:我国降水中的主要阴离子为硫酸根,其离子当量浓度占比为19.4%~32.9%,2003年以来年平均降低0.6个百分点;降水中的主要阳离子为钙离子和铵离子;硫酸根沉降通量年平均下降0.68 t/km2,硝酸根沉降通量年平均降低0.05 t/km2,全国SO2浓度变化趋势与硫酸根沉降通量变化趋势基本一致;我国降水中的硝酸根与硫酸根离子当量浓度比值总体呈升高趋势,表明硝酸根离子对降水酸度的影响逐渐增加,酸雨类型正由硫酸型向硫酸-硝酸混合型转变。 相似文献
913.
小清河入海口近十年水质变化及驱动因素分析 总被引:3,自引:3,他引:0
根据2008~2017年小清河入海口水体污染物浓度监测数据,选取13个污染因子,利用污染指数评价法、相关系数分析法以及主成分分析法等对入海径流水质变化进行了分析,并研究影响水质变化的驱动因素.结果表明, 2008~2017年,小清河入海口水质呈好转状态,污染状况大大减轻;不同污染因子超标情况有所差异,化学需氧量、石油类污染物超标情况最严重,磷类污染物次之,其他污染物基本符合Ⅲ类水质标准;石油类、化学需氧量、氨氮、亚硝酸盐氮和砷等污染物的污染程度整体呈下降趋势,磷、硝酸盐氮以及重金属中的铜、镉、铅、锌、汞和六价铬等污染物的污染程度呈不同程度上升趋势;污染物排放以及土地利用类型的变化是小清河水质整体上较差的主要因素,污水处理率的提高以及水环境保护政策的实施是小清河水质明显改善的重要原因,温度、日照时长、降水和瞬时径流等气候和水文因素也间接影响小清河入海径流的水质. 相似文献
914.
915.
Elizabeth J. Golebie Miriam Aczel Jacob J. Bukoski Sophia Chau Natali Ramirez-Bullon Mimi Gong Noah Teller 《Conservation biology》2022,36(1):e13850
Management of mangrove ecosystems is complex, given that mangroves are both terrestrial and marine, often cross regional or national boundaries, and are valued by local stakeholders in different ways than they are valued on national and international scales. Thus, mangrove governance has had varying levels of success, analyzed through concepts such as principles of good governance and procedural justice in decision-making. Although there is substantial research on case studies of mangrove management, global comparisons of mangrove governance are lacking. This research aims to fill this gap by comparing relationships among qualities of governance across mangrove social-ecological systems worldwide. Through a systematic literature search and screening process, we identified 65 articles that discussed mangrove governance and conservation. Case studies in these articles, drawn from 39 countries, were categorized as top-down, bottom-up, or comanaged and thematically coded to assess the influence of eight principles of good governance in mangrove conservation success. Across all three governance systems, the principles of legitimacy, fairness, and integration were most important in determining conservation success or failure. These principles are closely related to the concept of procedural justice, highlighting the importance of stakeholder inclusion throughout all stages of mangrove management. Thus, we recommend clearly defined roles for all governance actors, transparent communication of policy development to stakeholders, fairness in both process and outcome, and careful consideration of sustainable access to conservation resources. 相似文献
916.
Area protection is a major mechanism deployed for environmental conservation in Antarctica. Yet, the Antarctic protected areas network is widely acknowledged as inadequate, in part because the criteria for area protection south of 60°S are not fully applied. The most poorly explored of these criteria is the type locality of species, which provides the primary legal means for Antarctic species-based area protection and a method for conserving species even if little is known about their habitat or distribution. The type locality criterion has not been systematically assessed since its incorporation into the Protocol on Environmental Protection to the Antarctic Treaty in 1991, so the extent to which the criterion is being met or might be useful for area protection is largely unknown. To address the matter, we created and analyzed a comprehensive database of Antarctic type localities of terrestrial and lacustrine lichens, plants, and animals. We compiled the database via a literature search of key taxonomic and geographic terms and then analyzed the distance between type localities identifiable to a ≤ 25km2 resolution and current Antarctic Specially Protected Areas (ASPAs) and human infrastructure. We used a distance-clustering approach for localities outside current ASPAs to determine candidate protected areas that could contain these unprotected localities. Of the 386 type localities analyzed, 108 were within or overlapped current ASPAs. Inclusion of the remaining 278 type localities in the ASPA network would require the designation of a further 105 protected areas. Twenty-four of these areas included human infrastructure disturbance. Given the slow rate of ASPA designation, growing pace of human impacts on the continent, and the management burden associated with ASPAs, we propose ways in which the type locality criterion might best be deployed. These include a comprehensive, systematic conservation planning approach and an alternative emphasis on the habitat of species, rather than on a single locality. 相似文献