城市空气悬浮颗粒物时空变化规律及影响因素研究进展

对城市空气颗粒物的季节、日动态变化和空间分布规律作了综述,并探讨了人为活动、气象和特殊天气因素等对城市空气颗粒物水平的影响,最后提出目前关于城市空气悬浮颗粒物的研究中存在的问题及今后研究的发展方向。     

深圳湾浮游动物的群落结构及季节变化

2008年2月、5月、8月和11月分别对深圳湾浮游动物进行了周年的季节调查,结果共检出浮游动物38种和浮游幼体13类,其中原生动物2种,腔肠动物4种,介形类1种,桡足类22种,软甲类3种,毛颚类3种,被囊类1种,多毛类2种,浮游幼体（包括仔鱼）13类。年均丰度和生物量分别为406.7 ind.m-3和764.0 mg.m-3,高峰均位于夏季,低谷分别位于冬、春季。种类数（包括浮游幼虫）秋季最多为43种,夏季次之为30种,冬季最少仅23种。主要优势种为太平洋纺锤水蚤Acartia pacifica、刺尾纺锤水蚤Acartia spinicauda、短角长腹剑水蚤Oithona brevicornis、双生水母Diphyes chamissonis、卡玛拉水母Malagazzia carolinae、蔓足类幼体和桡足幼体等。多样性指数和均匀度年均值分别为2.568和0.526。回归分析表明浮游动物丰度和生物量与各环境因子之间存在明显的相关性,但有季节变化。     

北京市城市湖泊上空甲烷浓度水平和季节特征

通过对北京市市区内大于10 000 m2的10个湖泊上空0.5 m处甲烷浓度的季度观测,研究了北京市城市湖泊上空甲烷的浓度水平,并对其中4个典型的湖泊进行了每月1~2次的观测,分析了城市湖泊上空甲烷浓度的连续变化特征。结果表明湖泊上空甲烷浓度年平均值为2.337±0.431 mL/m3,高于全球均值和其他相关研究人员对北京市上空监测的结果。湖泊上空甲烷浓度季节之间的差异性显著(P<0.01),夏季的甲烷浓度较高(2.758±0.516mL/m3),秋季和春季相对较低。4个典型湖泊上空甲烷浓度连续变化具有一定的规律,大都在7-8月份达到甲烷浓度的高峰期,3月初融冰时都会有小幅增加;位于市中心的什刹海上空甲烷浓度相对较高。这表明了北京市内湖泊是甲烷排放的一个重要源头,同时也反映了北京作为一特大城市,其湖泊上空甲烷浓度受人类活动影响的特征。     

广州大气低分子量羰基化合物的季节变化

对广州市区荔湾和五山两个代表性采样点的低分子量羰基化合物(甲醛、乙醛、丙酮和丙醛)进行了季节变化研究.实验方法是应用羰基化合物和2,4-二硝基苯肼(DNPH)迅速反应生成衍生物,产物在高效液相色谱上检测.按冬、夏两季进行样品采集,每次连续采样4 d.研究发现丙酮质量浓度最高,其次是甲醛和乙醛.夏季的羰基化合物质量浓度值高于冬季的.除丙酮外,甲醛、乙醛、丙醛的质量浓度是荔湾采样点高于五山采样点.甲醛/乙醛、乙醛/丙醛质量浓度比值显示广州大气中羰基化合物主要与人为来源有关.羰基化合物之间的相关性冬季好于夏季,暗示羰基化合物冬季来源比夏季简单.羰基化合物的来源主要有汽车排放、大气光化学反应,还可能与植物排放、烟草烟气、实验室所用溶剂有关.     

深圳湾浮游植物的季节变化

2008年2月至11月对深圳湾的浮游植物和理化环境因子进行了4个季度月的调查,结果共检出浮游植物150种（包括变种和变型）：春季66种、夏季72种、秋季54种、冬季50种,其中硅藻门36属108种,甲藻门14属36种,绿藻门3属3种,蓝藻门2属3种。优势种共有湖沼圆筛藻Coscinodiscus lacustris、中肋骨条藻Skeletonema costatum、夜光藻Noctiluca scientillans 3种：春季1种、夏季1种、秋季1种、冬季2种,优势种群由春夏季的湖沼圆筛藻演替至秋季的中肋骨条藻、冬季的中肋骨条藻和夜光藻,没有全年广布优势种;4季均出现的种类共有9种,其中硅藻8种,甲藻1种,各季节间共有种类数在13～31种,Jaccard种类相似性指数范围在0.12~0.35,季节更替明显。多样性指数和均匀度的变化范围分别为0.006~1.724和0.001~0.306,群落结构较脆弱。细胞密度在1.25×107~217.90×107 cells.m-3,夏季最高,春季次之,冬季最低,属季节单峰型变化,与一般亚热带春、秋季出现密度高峰不一致,这与深圳湾陆源营养物质的扰动有关,其无机氮和活性磷酸盐含量均劣于国家海水水质标准的四类水,因此,该海域水质营养类型属于亚热带富营养型。细胞密度与硅酸盐呈极显著的负相关,相关系数为-0.446（p〈0.01,n=36,双尾）,与水温呈显著的正相关,相关系数为0.371（p〈0.05,n=36,双尾）,与其他因子的相关性不明显。从优势种的种类数和多样性指数分析,深圳湾浮游植物的群落结构已趋于单一化,生态系统抗干扰能力极为脆弱。     

日光温室环境空气的变化规律及质量评价

为明确日光温室环境空气质量的变化规律,采用实地固点监测的方法,选取1、5和10 a棚龄的日光温室,分别对其室内温度、相对湿度、可吸入颗粒物(PM10)、总悬浮物(TSP)及Cl2、NH3、NO、O3进行监测,并对室内空气质量进行评价。结果表明,温室内温湿度、气体浓度变化与外界气象条件变化关系密切,温室内PM10和TSP浓度随棚龄的增大而逐渐升高。不同棚龄温室内Cl2、NH3、NO和O3浓度日、月变化规律一致,Cl2、NH3和O3浓度峰值出现在午后,NO浓度峰值出现在揭苫和盖苫前后,且O3与NO浓度呈负相关(r=-0.964),1、5和10 a棚龄的日光温室内Cl2日平均浓度和NH3日最高浓度均超过国家标准,而NO和O3浓度未超标。温室内PM10和TSP浓度以10 a棚龄温室为最高,1 a棚龄温室为最低。1—2月温室内PM10和TSP浓度最高,且10 a棚龄温室内PM10超过国家标准。     

沈阳市大气PM2.5中水溶性离子的季节变化特征

为研究沈阳市大气中PM2.5及其水溶性离子的污染特征、季节差异和来源情况,使用URG-9000D在线监测系统对沈阳市2019年大气颗粒物进行连续的采样分析,并利用正交矩阵因子分析法(PMF)进行污染物的来源解析.结果 表明,2019年沈阳市秋冬季节PM2.5质量浓度变化受相对湿度影响较大,冬季PM2.5平均质量浓度达到...     

临汾市PM2.5中水溶性离子季节变化特征及来源解析

利用在线监控平台获得临汾市2019年3月1日至2020年2月29日PM2.5的24 h均值及其中8种水溶性离子(NO3-、SO42-、NH4+、Cl-、K+、Na+、Mg2+和Ca2+)的监测数据,分析了PM2.5及水溶性离子浓度的季节变化特征,采用主成分分析法探讨了各种离子的主要来源.结果 表明,在研究期内,临汾市P...     

荣成人工湿地净化效果的季节和年际变化

荣成人工湿地污水处理系统占地面积80 hm2,处理规模2.0万m3.d-1,1998年10月开始投入运行。对1999年1月到2004年12月荣成人工湿地污水处理系统净化效果以及净化效果的季节和年际变化进行分析。结果表明,人工湿地对SS、BOD5、CODC r均有很好的去除效果,出水浓度分别为(27.6±6.6)、(22.7±4.3)和(90.0±12.5)mg.L-1,去除率分别为73.9%、72.5%和63.8%。大肠菌群、粪大肠菌群去除率分别为99.7%和99.6%。对NH4 -N和TP去除效果较差,出水浓度分别为(11.2±2.7)和(2.03±0.29)mg.L-1,去除率分别为45.1%和30.2%。BOD5、CODC r、NH4 -N和TP的去除效果与季节变化有一定关系,NH4 -N受季节变化的影响最大,其次是TP,BOD5和CODC r受季节变化的影响相对较小。分析BOD5、CODC r、NH4 -N和TP去除效果的年际变化发现,BOD5、CODC r和NH4 -N去除率有增加的趋势。TP去除率在2001年和2002年基本相同,从2003年开始下降。     

北京大气颗粒物中多环芳烃浓度季节变化及来源分析

使用大流量滤膜采样器,从2006年9月至2007年8月,每周同时采集北京城市大气可吸入颗粒物(PM10)和细粒子样品(PM2.5)各一次,二氯甲烷超声抽提一气相色谱/质谱分析了17种多环芳烃(PAHs)浓度,结果表明,春、夏、秋、冬四季北京大气PM10和PM2.5中PAHs总量分别为63.8±44.6ng·m-3、43.2±4.5ng·m-3、84.7±108.3ng·m-3、348.0±250.0ng·m-3和54.7±17.3ng·m-3、40.3±8.6ng·m-3、66.1±81.5ng·m-3、337.7±267.2ng·m-3;约有70%的PAHs存在于细粒子PM2.5中,其质量浓度有明显季节变化,冬季>秋季>春季>夏季;颗粒物中PAHs主要以4、5、6环存在,其中4环以上占79.4%.源解析表明,北京大气颗粒物中的PAHs主要来自燃煤,同时汽油、柴油燃烧排放也不能忽略.结合气象要素分析,温度升高和太阳辐射增强易造成多环芳烃挥发和反应,湿沉降有利于多环芳烃随颗粒物清除.     

Firm incentives to promote technological change in pollution control

The process of technological change in pollution control is broken into three basic steps: innovation, diffusion, and optimal agency response. Firm incentives to promote these steps are then examined under five regulatory regimes: direct controls, emission subsidies, emission taxes, free marketable permits, and auctioned marketable permits. On a relative basis, emission taxes and auctioned permits provide the highest firm incentives to promote technological change; at times, free permits generate lower incentives. Direct controls, which are common regulatory tools, usually provide the lowest relative firm incentives to promote technological change.     

Estimation of the cost of air pollution control regulation

Estimates of hydrocarbon pollution control costs under the alternative regulatory approaches of individual source or process standards, plant standards, and regionally marketable permits are presented. The estimates are obtained from data supplied by the DuPont Company based on a 1976 in-house engineering study. The estimation procedure is unique in that the data are based on uniform percentage control across sources while the estimated cost equations allow variable control at each source. The cost simulations show that considerable cost savings are available from allowing firms more flexibility in meeting a given environmental standard. The effect of plant relocation and monopoly in the pollution permit market are also investigated.     

On estimating air pollution control benefits from land value studies

This paper deals with some unresolved issues in interpreting empirical property value/air pollution studies. A model is developed in which it is shown that in general regressions of property values on pollution variables do not identify the demand curve for clean air. However since the first derivative of the observed rent function is a locus of household equilibrium marginal willingnesses to pay, aggregate benefits can be calculated directly. The possibilities for obtaining approximate measures of aggregate benefits for nonmarginal changes in air quality are also discussed.     

Firm incentives to promote technological change in pollution control: Comment

Following on from an analysis by Milliman and Prince, this article considers further the relative incentives for technical change provided by different pollution control instruments. The comments involve the recognition that emission targets are typically chosen fairly arbitrarily because of regulators' lack of knowledge of abatement cost schedules. There is also a more detailed discussion of the practicability of auctioning emissions permits, as these have been less thoroughly covered in the literature than the other instruments.     

Firm incentives to promote technological change in pollution control: Reply

Our paper (Firm incentives to promote technological change in pollution control, J. Environ. Econom. Management 17, 247–265 (1989)) concluded that firms will most actively search for new abatement technology under taxes and auctioned permits. However, Marin (Firm incentives to promote technological change in pollution control: Comment, J. Environ. Econom. Management, 21, 297–300 (1991)) argues that we overstated the efficacy of auctioned permits: that we used an unrealistic assumption which might affect our findings; that auctions may misallocate permits and are administratively burdensome; and that innovation detection is difficult under this regime. Here we show that our results are largely unchanged when the assumption questioned by Marin is relaxed. We also argue that he overstates the other concerns.     

Long-term exposure to air pollution and cerebrovascular disease: findings from Beijing Health Management Cohort study

● This study explored the long-term association by double robust additive models. ● Individual exposure concentrations were assessed by integrating GAM, LUR and BPNN. ● PM_2.5, SO₂ and NO₂ are positively associated with cerebrovascular disease. ● CO could reduce the risk of cerebrovascular disease with the highest robustness. ● The elderly, women and people with normal BMI are at higher risk for air pollution. The relationship between air pollution and cerebrovascular disease has become a popular topic, yet research findings are highly heterogeneous. This study aims to investigate this association based on detailed individual health data and a precise evaluation of their exposure levels. The integrated models of generalized additive model, land use regression model and back propagation neural network were used to evaluate the exposure concentrations. And doubly robust additive model was conducted to explore the association between cerebrovascular disease and air pollution after adjusted for demographic characteristics, physical examination, disease information, geographic and socioeconomic status. A total of 25097 subjects were included in the Beijing Health Management Cohort from 2013 to 2018. With a 1 μg/m³ increase in the concentrations of PM_2.5, SO₂ and NO₂, the incidence risk of cerebrovascular disease increased by 1.02 (95% CI: 1.008–1.034), 1.06 (95% CI: 1.034–1.095) and 1.02 (95% CI: 1.010–1.029) respectively. Whereas CO exposure could decrease the risk, with an odds ratio of 0.38 (95% CI: 0.212–0.626). In the subgroup analysis, individuals under the age of 50 with normal BMI were at higher risk caused by PM_2.5, and SO₂ was considered more hazardous to women. Meanwhile, the protective effect of CO on women and those with normal BMI was stronger. Successful reduction of long-term exposure to PM_2.5, SO₂ and NO₂ would lead to substantial benefits for decrease the risk of cerebrovascular disease especially for the health of the susceptible individuals.     

Intercontinental transport of air pollution

There is an increasing interest on the intercontinental transport of air pollution among the three main emission regions at northern mid-latitudes: North America, Europe, and East Asia. Air pollutants with sufficient long lifetime can be transported from one continent to another. Observations from ground sites, aircraft and satellites have demonstrated this intercontinental-scale transport of air pollutants in the free troposphere. Numerical models have been applied to understand the pathways of the transport and the impact of intercontinental pollution transport. This paper reviews current observational evidence and modeling studies of intercontinental transport of ozone and its precursors, and the resulting impacts on air quality.