武汉市夏季大气中PAN和O3污染特征分析

采用在线监测设备对2020年9月武汉大气中光化学污染物PAN、O₃以及气象条件进行实时监测,对PAN和O₃变化特征和日变化规律进行分析,并将PAN和O₃体积分数与气象观测数据和后向轨迹相结合,综合分析输送特征以及污染状况。观测期间,武汉城区大气中PAN体积分数平均值为(0.68±0.53)×10^-9,最大小时体积分数为2.79×10^-9,O₃体积分数平均值为(54.56±22.44)×10^-9,最大小时体积分数为108.73×10^-9。PAN与O₃间存在相似的日变化趋势,PAN与O₃均是碳氢化合物与氮氧化物光化学反应的产物,通过相关性分析PAN和O₃体积分数相关系数为R²=0.61,城市大气中大多数反应性VOCs都能生成O₃,而PAN仅由能产生CH₃CO₃自由基...     

大气中O3与CO2浓度升高对植物影响研究进展

由于工业的快速发展,大气中的O₃和CO₂浓度有逐年上升的趋势,对植物产生了很大的影响。目前,植物对O₃和CO₂浓度变化的复合作用的响应机制研究已经成为生态学研究的热点问题。文中阐述了O₃和CO₂浓度升高及其复合作用对植物的形态特征、光合作用、抗氧化系统及生物量等生理生化机制的影响,指出目前研究中存在并有待进一步研究的问题,以期为进一步开展高浓度O₃和CO₂对植物生理生态学影响研究提供科学参考和理论依据。     

江津城区大气污染特征及常规污染物分析

采用2018～2021年江津城区自动监测站点监测数据,分析了城区空气质量状况和污染特征,结果表明：(1)江津城区首要污染物常年以PM_2.5和O₃为主,短期内不会改变;(2)城区的O₃污染天气主要集中在春夏,以轻度污染为主,O₃浓度有上升趋势,PM_2.5污染天气主要集中在秋冬季节,年超标天数约为40 d, PM_2.5污染状况亟需进一步改善;(3)PM_2.5和O₃的有较高的相关性,冬季主要为负相关,春季逐步变为正相关,夏季相关系数最大,NO₂和O₃之间的相关性呈季节性,冬季呈负相关,春夏呈为正相关,且相关性显著。     

汕尾市臭氧污染变化特征分析

指出了O₃作为汕尾市空气污染的首要污染物,研究汕尾市O₃浓度变化特征对全面掌握汕尾市空气质量概况具有重要意义。以汕尾市城市国控空气自动监测站2014～2021年的监测数据为基础,结合气象资料,分析了汕尾市O₃变化趋势及相关气象因子影响。结果表明：2014年以来,汕尾市的O₃-8h(90百分位浓度)质量浓度在130～153μg/m³之间,总体上汕尾市O₃污染的变化特征与广东省整体趋势基本一致,O₃污染未继续恶化。从多年月平均看,6～8月份汕尾市O₃质量浓度相对较低,冷热交替的月份(10月与4月)的质量浓度相对较高。O₃浓度日变化为昼高夜低,峰值在15:00左右,与NO₂呈反相关关系。     

安徽省部分地区大气污染现状分析与评估

对比分析了安徽省部分城市2016～2020年6种污染指标的浓度和AQI的观测数据。结果表明：2016～2020年间安徽省大气污染物PM_2.5、PM₁₀、SO₂、CO,NO₂浓度整体都呈现下降趋势,而O₃浓度整体呈现上升趋势;安徽省AQI随季节变化明显呈现出冬季首要污染物主要为PM_2.5,夏季首要污染物主要为O₃,首要污染物为细颗粒物的天数逐年下降,无首要污染物的天数在逐年上升。     

苏南某地2022年大气污染物变化特征及相关性分析

分析了苏南某地2022年大气污染物监测数据。结果表明：某地主要超标污染物为O₃和PM_2.5,O₃月均值占标率呈双峰变化,其他污染物呈“U”形变化,O₃高值日的O₃小时浓度在11:00—19:00均处在较高位,PM_2.5高值日的PM_2.5小时值全天处于较高水平。各污染物月均值相关性分析,NO₂与CO、PM_2.5正相关且相关性较大,O₃与NO₂、CO负相关,PM_2.5与NO₂、CO正相关;日均值相关性分析,1-3月份、11-12月份,PM_2.5与PM₁₀的相关系数在0.8以上,4-10月份,O₃与PM_2.5、PM₁₀的相关性较好。在O₃和PM_2.5超标的情况...     

植物de监测作用

有些植物对大气污染的反应远比人敏感得多，例如人在二氧化硫浓度达1—5ppm时，嗅觉才能感觉到；10—20ppm时才有刺激感觉。而某些敏感植物处在0．3ppm浓度下几小时，就会出现受害症状。有些气体毒性很大（如有机氟），但无色无臭，不易感觉。然而某些植物却能及时作出反应。因此利用某些敏感植物来监测大气中有毒气体的浓度，指示环境的污染程度是十分可靠而又方便的办法。关于植物对大气中常见有毒气体的敏感性、抗性和吸收力的测定，我国和欧美、日本都作了大量调查和实验，找出了一批敏感性很强的监测植物。当然同一植物对不同的有毒气…     

永泰县域臭氧时空分布特征及其相关因素分析

以2019～2021年永泰县环境空气自动站监测数据为基础,运用Excel、Origin、SPSS等软件分析了臭氧(O₃)时空分布特征,O₃与气象要素、O₃前体物(CO、NO₂)相关性,并结合Hysplit模型对O₃超标事件进行了分析。结果表明：(1)2019～2021年O₃浓度变化趋势明显向好;月O₃浓度受气象条件、排放源、外来输入等影响,各年份间最高值与最低值出现的时间不同;日变化呈单峰型;(2)各站点O₃浓度除2020年青云山站略低于城南小学站外,总体上浓度大小为：青云山站>城南小学站>上马路站;(3)O₃与气压、CO、NO₂相关性不明显,与气温、日照、风速呈正相关,与降水、相对湿度呈负相关,高值出现在风向为东南或南期间;(4)上马路站超标原因主要为当地生成累积导致。同时从提升监测能力、实施VOCS和NO_X专项整治行动、强化联防联控...     

大夫山森林公园大气环境中污染物浓度变化及评价

利用长期定位观测方法对大夫山森林公园的大气质量进行监测,分析了大夫山森林公园大气污染源的种类、数量、分布规律,包括NO、NO₂、NO_x和SO₂浓度的日变化规律、季节变化规律进行了探讨。在此基础上,通过分析森林公园大气污染物超标率和分担率情况来评价大夫山森林公园大气质量的影响。结果表明,大夫山森林公园的大气质量非常良好,SO₂和NO_x秋冬季对大气环境有轻微污染,污染分担率最大的SO₂,其次是NO_x,而NO和NO₂对大夫山森林公园环境不产生影响。为进一步提高森林公园的大气环境质量,建议增加冬季常绿阔叶树种。       

“十三五”期间襄阳市环境空气质量时空变化特征分析

基于“十三五”期间(2016～2020年)襄阳市6种大气污染物监测数据,对襄阳市各污染物时空变化特征及影响因素进行了分析,结果表明：(1)“十三五”期间襄阳市CO、SO₂、PM₁₀均呈下降趋势,PM_2.5、NO₂除2020年有所下降,无明显变化趋势,O₃除了2019年出现一个明显峰值,总体保持在140μg/m³左右水平;(2)襄阳市大气污染物质量浓度表现出明显的季节性特征,PM₁₀、PM_2.5、SO₂、NO₂、CO的质量浓度均为冬季最高、夏季最低;O₃则呈相反变化趋势;(3)2020年襄阳市空气污染物浓度在空间分布上总体呈现出PM₁₀、PM_2.5西低东高、中间区域较高,O₃、SO₂北高南低,NO₂西低东高,CO北低南高的规律。     

Risk assessment of ozone impact on <Emphasis Type="Italic">Fagus crenata</Emphasis> in Japan: consideration of atmospheric nitrogen deposition

Tropospheric ozone (O₃) is considered to be the air pollutant relating to the decline of Fagus crenata forest in Japan. In the present study, we assessed a risk of O₃ impact on the growth of F. crenata in Japan, giving consideration to the effects associated with atmospheric nitrogen (N) deposition based on the experimental study, national monitoring data for oxidant concentration and atmospheric N deposition, and a national vegetation survey. The average and maximum O₃-induced relative growth reduction (RG_red) of F. crenata across Japan were estimated to be 3.2 and 9.7%, respectively. Current levels of atmospheric N deposition were found to significantly affect the sensitivity of F. crenata to O₃. When the N deposition was assumed as zero, the estimated average and maximum RG_red were 2.3% and 5.7%, respectively. The inclusion of atmospheric N deposition data thus increased the estimated values for average and maximum RG_red (by 38% and 71%, respectively). Our results demonstrate that a change in the sensitivity to O₃ associated with atmospheric N deposition is an important consideration in the risk assessment of O₃ impact on the growth of F. crenata in Japan.     

Effects of atmospheric and climate change at the timberline of the Central European Alps

? This review considers potential effects of atmospheric change and climate warming within the timberline ecotone of the Central European Alps. After focusing on the impacts of ozone (O₃) and rising atmospheric CO₂ concentration, effects of climate warming on the carbon and water balance of timberline trees and forests will be outlined towards conclusions about changes in tree growth and treeline dynamics.

? Presently, ambient ground-level O₃ concentrations do not exert crucial stress on adult conifers at the timberline of the Central European Alps. In response to elevated atmospheric CO₂ Larix decidua showed growth increase, whereas no such response was found in Pinus uncinata. Overall climate warming appears as the factor responsible for the observed growth stimulation of timberline trees.

? Increased seedling re-establishment in the Central European Alps however, resulted from invasion into potential habitats rather than upward migration due to climate change, although seedlings will only reach tree size upon successful coupling with the atmosphere and thus loosing the beneficial microclimate of low stature vegetation.

? In conclusion, future climate extremes are more likely than the gradual temperature increase to control treeline dynamics in the Central European Alps.

     

Injury to Eastern White Pine by Sulfurdioxide and Ozone Alone and in Mixtures

Clones of eastera white pine (Pinus strobus) selected for their sensitivity to sulfur dioxide (SO₂) were fumigated in a controlled environment chamber. Sulfur dioxide alone and in combination with ozone (O₃) at concentration 5 parts per hundred million (pphm) of air by volume of each gas for independent 2-hr exposures was toxic to new needles. Severest injury resulted from a discontinuous fumigation with 5 pphm O₃ and 5 pphm SO₂for 2 hr in separate fumigations, followed 24 hr later by a 2-hr exposure to a mixture of these gases, each at 5 pphm. The rapidity of lesion development and total injury to new needles were less following a single 2-hr fumigation with an O₃-SO₂mixture than when a single 2-hr fumigation with SO₂alone was used. Ozone and SO₂reacted to reduce injury. These plants were not injured by O₃used alone. New needles receiving only filtered air or new needles on resistant plants were not visibly affected by any treatment. Acute injury induced by the O₃-SO₂mixture developed differently from injury induced by SO₂alone.     

Response of spruce stands in national parks of southern Poland to air pollution in 1998–2005

The purpose of this study was to describe changes in the deposition of air pollutants and the response of spruce trees in the period of 1998–2005. The investigation was carried out in twelve sites, mainly national parks. Air pollution level, that is, SO₂, NO₂, and O₃ concentrations in the air, as well as throughfall and soil solution chemical composition was analysed. The reaction of trees was described based on a stand health parameter, that is, defoliation. A decrease in the concentration of SO₂ and NO₂ in the investigated period was observed. In most of the analysed sites, ozone concentrations in the growing season exceeded the level regarded as harmful to plants. Annual loads of nitrogen and sulphur reaching the forest soil exceeded 10 kg/ha. The data collected for the analysed period confirmed that the health status of forests at the investigated sites did not show a general tendency towards improvement. Also, no dependency between the air pollution level and defoliation rate was found.     

The influence of SO2 on CO2 uptake and peroxidase activity

This study confirms that CO₂ uptake of European conifers increases during needle maturation. Extensive investigations with grafts of several species show that this increase may even mask a deleterious effect of a weak SO₂ stress. In plants which are not dependent on air-borne SO₂ for S nutrition CO₂ uptake was not favored by SO₂. Peroxidase activity of tree foliage may be a valuable stress indication, particularly in areas with light air pollution. It is, however, not specific for air pollution and seems to be most suitable for “active” monitoring.     

Risk assessment of ozone impact on the carbon absorption of Japanese representative conifers

A risk assessment of ozone (O₃) impact on the annual carbon absorption (ACA) of Japanese representative conifers was conducted based on the results of an experimental study, monitoring data of oxidant concentrations and vegetation surveys. The areas with high O₃-induced reduction in ACA did not necessarily correspond to the areas with relatively high O₃-exposure. Widespread distribution of O₃-sensitive tree species such as Pinus densiflora and Larix kaempferi, and high ACA were important factors that induced a high risk of O₃ impact on the ACA. Therefore, we concluded that not only the accumulated O₃-exposure but also the variety of tree habitat, the tree sensitivity to O₃ and the ACA among the tree species must be taken into account to assess the risk of O₃ impact on the ACA of Japanese conifers. The O₃-induced reduction in the total ACA of the three tree species in Japan was estimated to be 0.8%.     

大气污染的植物修复研究进展

大气污染是人类面临的严重环境问题之一,植物除了可以监测大气的污染外,在近地表大气污染物的清除中起着重要作用。利用植物净化大气污染物是1种低碳、有效、非破坏型的环境污染修复方式,植物净化污染大气的思想及其技术对城市园林绿化、环境规划和生态环境建设等具有直接的指导意义和应用价值。笔者介绍了大气污染的种类、植物净化大气污染的机理、植物净化大气污染的主要过程,提出了筛选高效净化植物、开发联合修复技术、培育转基因净化植物及合理植物配置等是未来研究的主要方向。     

Deciphering the ozone-induced changes in cellular processes: a prerequisite for ozone risk assessment at the tree and forest levels

Key message

Ozone, one of the major atmospheric pollutants, alters tree growth, mainly by decreasing carbon assimilation and allocation to stems and roots. To date, the mechanisms of O₃ impact at the cellular level have been investigated mainly on young trees grown in controlled or semi-controlled conditions. In the context of climate change, it is necessary to introduce a valuable defence parameter in the models that currently predict O₃ impact on mature trees and the carbon sequestration capacity of forest ecosystems.

Context

Air pollution is an important factor that affects negatively forest ecosystems. Among oxidative air pollutants, ozone is considered as the most toxic in terms of impact on vegetation.

Aims

This paper focuses on the negative impacts of ozone on trees in controlled conditions or in their natural environment. The current knowledge of the responses at cell level is presented and ways to improve their use for ozone risk assessment of forest stands are discussed.

Methods

Information was collected from original papers or reviews, providing an overview of the research conducted over the last 60 years.

Results

The negative effects of ozone on carbon assimilation and tree biomass production were reviewed and discussed, with a focus on effects on cell processes implied in cell defence, including stomatal regulation, detoxification, signalling, and biosynthesis of wood compound.

Conclusion

In the context of increasing significance of O₃ flux approach, this review intends to shed light into the black box of defence processes, which are playing a crucial part within the effective O₃ dose modelling. Today, it is recognized that tropospheric ozone inhibits tree growth and its role on the future carbon sink of the forest ecosystem is discussed along with the combination of other environmental factors like elevated temperature, water, and nitrogen supply, likely to be modified in the context of climate change.

     

Effects of acidic fog and ozone on the growth and physiological functions of Fagus crenata saplings

The effects of simulated acid fog (SAF) and ozone (O₃) stress on the growth and physiology of beech (Fagus crenata) saplings were investigated. Three-year-old beech saplings were exposed to SAFs of pH 3 and pH 5 (control) during May 2007 to July 2008. In each SAF treatment group, half of the saplings were exposed to 60 ppb of O₃ during September 2007 to July 2008. In comparison to the control saplings, those from the pH 3 treatment had lower total plant biomasses, epicuticular wax amounts, Ca²⁺ concentrations in their leaves, and lower starch concentrations in their leaves and roots. The effect of O₃ was significant only for the starch concentration in the roots, but the O₃ exposure also negatively affected the growth and physiology of beech saplings. Results show that acid fog exerts various severe effects, and that both chronic acid fog and O₃ exposure suppressed the physiological functions of beech saplings.     

Growth recovery of mature Norway spruce and European beech from chronic O<Subscript>3</Subscript> stress

Elevated O₃ levels can strongly impair the health and vitality of forest ecosystems. Free-air exposure systems reveal that forest tree and stand growth can be reduced strongly under chronic O₃ stress. Detailed knowledge of the effect of O₃ exposure on photosynthesis, carbon sequestration, allometry and growth during chronic stress is available. However, knowledge of growth response after O₃ reduction is scarce. Here, we analyse the growth of mature Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) in the free-air O₃ fumigation experiment at Kranzberg Forest. We compare tree growth over a 9-year period (2008–2016) after exposure to O₃ (2000–2007). During 2?×?O₃ exposure, the annual basal area growth of Norway spruce and European beech decreased by 24 and 32%, respectively. After cessation of 2?×?O₃ exposure, the annual basal area growth of Norway spruce and European beech not only recovered but exceeded the growth of the trees in the control condition by 14 and 24%, respectively. The growth resilience and resistance of trees previously exposed to 2?×?O₃ towards drought stress and late frost was hardly lower than that of the trees in the control condition. The capacity for growth recovery even after long-term chronic O₃ stress emphasizes the strong beneficial effect of air pollution control on the health of forest ecosystems and on the global land carbon sink.