| 1. |
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| 2. |
- Hallquist, Mattias, 1969, et al.
(författare)
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Photochemical smog in China: scientific challenges and implications for air-quality policies
- 2016
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Ingår i: National Science Review. - : Oxford University Press (OUP). - 2095-5138 .- 2053-714X. ; 3:4, s. 401-403
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Tidskriftsartikel (refereegranskat)abstract
- In large areas of China severe air pollution events pose a significant threat to human health, ecosystems and climate. Current reduction of primary emissions will also affect secondary pollutants such as ozone (O3) and particulate matter (PM), but the magnitude of the effects is uncertain. Major scientific challenges are related to the formation of O3 and secondary particulate matter including Secondary Organic Aerosols (SOA). Large uncertainties also remain regarding the interactions of soot, SOA and O3 under the influence of different SO2, NOX and VOC concentrations. To improve the understanding of these secondary atmospheric interactions in China, scientific areas of central importance for photochemically induced air pollutants have been identified. In addition to the scientific challenges, results from research need to be synthesized across several disciplines and communicated to stakeholders affected by air pollution and to policy makers responsible for developing abatement strategies. Development of these science-policy interactions can benefit from experience gained under the UN ECE Convention on Long Range Transboundary Air Pollution (LRTAP)
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| 3. |
- Andersson-Sköld, Yvonne, et al.
(författare)
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A framework for assessing urban greenery's effects and valuing its ecosystem services
- 2018
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Ingår i: Journal of Environmental Management. - : Academic Press. - 0301-4797 .- 1095-8630. ; 205, s. 274-285
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Tidskriftsartikel (refereegranskat)abstract
- Ongoing urban exploitation is increasing pressure to transform urban green spaces, while there is increasing awareness that greenery provides a range of important benefits to city residents. In efforts to help resolve associated problems we have developed a framework for integrated assessments of ecosystem service (ES) benefits and values provided by urban greenery, based on the ecosystem service cascade model. The aim is to provide a method for assessing the contribution to, and valuing, multiple ES provided by urban greenery that can be readily applied in routine planning processes. The framework is unique as it recognizes that an urban greenery comprises several components and functions that can contribute to multiple ecosystem services in one or more ways via different functional traits (e.g. foliage characteristics) for which readily measured indicators have been identified. The framework consists of five steps including compilation of an inventory of indicator; application of effectivity factors to rate indicators' effectiveness; estimation of effects; estimation of benefits for each ES; estimation of the total ES value of the ecosystem. The framework was applied to assess ecosystem services provided by trees, shrubs, herbs, birds, and bees, in green areas spanning an urban gradient in Gothenburg, Sweden. Estimates of perceived values of ecosystem services were obtained from interviews with the public and workshop activities with civil servants. The framework is systematic and transparent at all stages and appears to have potential utility in the existing spatial planning processes.
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| 4. |
- Mills, Gina, 1959, et al.
(författare)
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Ozone pollution will compromise efforts to increase global wheat production
- 2018
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:8, s. 3560-3574
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Tidskriftsartikel (refereegranskat)abstract
- Introduction of high-performing crop cultivars and crop/soil water management practices that increase the stomatal uptake of carbon dioxide and photosynthesis will be instrumental in realizing the United Nations Sustainable Development Goal (SDG) of achieving food security. To date, however, global assessments of how to increase crop yield have failed to consider the negative effects of tropospheric ozone, a gaseous pollutant that enters the leaf stomatal pores of plants along with carbon dioxide, and is increasing in concentration globally, particularly in rapidly developing countries. Earlier studies have simply estimated that the largest effects are in the areas with the highest ozone concentrations. Using a modelling method that accounts for the effects of soil moisture deficit and meteorological factors on the stomatal uptake of ozone, we show for the first time that ozone impacts on wheat yield are particularly large in humid rain-fed and irrigated areas of major wheat-producing countries (e.g. United States, France, India, China and Russia). Averaged over 2010-2012, we estimate that ozone reduces wheat yields by a mean 9.9% in the northern hemisphere and 6.2% in the southern hemisphere, corresponding to some 85 Tg (million tonnes) of lost grain. Total production losses in developing countries receiving Official Development Assistance are 50% higher than those in developed countries, potentially reducing the possibility of achieving UN SDG2. Crucially, our analysis shows that ozone could reduce the potential yield benefits of increasing irrigation usage in response to climate change because added irrigation increases the uptake and subsequent negative effects of the pollutant. We show that mitigation of air pollution in a changing climate could play a vital role in achieving the above-mentioned UN SDG, while also contributing to other SDGs related to human health and well-being, ecosystems and climate change.
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| 5. |
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| 6. |
- Mills, Gina, 1959, et al.
(författare)
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Tropospheric Ozone Assessment Report: Present-day tropospheric ozone distribution and trends relevant to vegetation
- 2018
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Ingår i: Elementa-Science of the Anthropocene. - : University of California Press. - 2325-1026. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- This Tropospheric Ozone Assessment Report (TOAR) on the current state of knowledge of ozone metrics of relevance to vegetation (TOAR-Vegetation) reports on present-day global distribution of ozone at over 3300 vegetated sites and the long-term trends at nearly 1200 sites. TOAR-Vegetation focusses on three metrics over vegetation-relevant time-periods across major world climatic zones: M12, the mean ozone during 08:00-19:59; AOT40, the accumulation of hourly mean ozone values over 40 ppb during daylight hours, and W126 with stronger weighting to higher hourly mean values, accumulated during 08:00-19:59. Although the density of measurement stations is highly variable across regions, in general, the highest ozone values (mean, 2010-14) are in mid-latitudes of the northern hemisphere, including southern USA, the Mediterranean basin, northern India, north, north-west and east China, the Republic of Korea and Japan. The lowest metric values reported are in Australia, New Zealand, southern parts of South America and some northern parts of Europe, Canada and the USA. Regional-scale assessments showed, for example, significantly higher AOT40 and W126 values in East Asia (EAS) than Europe (EUR) in wheat growing areas (p < 0.05), but not in rice growing areas. In NAM, the dominant trend during 1995-2014 was a significant decrease in ozone, whilst in EUR it was no change and in EAS it was a significant increase. TOAR-Vegetation provides recommendations to facilitate a more complete global assessment of ozone impacts on vegetation in the future, including: an increase in monitoring of ozone and collation of field evidence of the damaging effects on vegetation; an investigation of the effects on peri-urban agriculture and in mountain/upland areas; inclusion of additional pollutant, meteorological and inlet height data in the TOAR dataset; where not already in existence, establishing new region-specific thresholds for vegetation damage and an innovative integration of observations and modelling including stomatal uptake of the pollutant.
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| 7. |
- Broberg, Malin, 1989, et al.
(författare)
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Effects of ozone, drought and heat stress on wheat yield and grain quality
- 2023
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Ingår i: Agriculture, Ecosystems & Environment. - 0167-8809. ; 352:15
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Tidskriftsartikel (refereegranskat)abstract
- Tropospheric ozone (O3) is a gaseous phytotoxic plant stressor known to reduce wheat (Triticum aestivum) crop yields at current concentrations. O3 is predicted to increase in many crop-growing regions, together with higher frequencies of heatwaves and droughts. In this study, wheat crops were exposed to two levels of O3 (ambient and ~70 ppb) in combination with ambient or elevated temperature (+8 ◦C) and two watering regimes (well-watered and 50% reduced water supply) during the grain-filling period. With this experimental setup, we assessed the interactive effects between O3, temperature and water supply on wheat yield and grain quality, and measured leaf gas exchange to explore the underlying mechanisms. Overall, O3, warming and drought all decreased grain yield and average grain mass but increased grain concentration of N and other nutrient elements. Increasing daytime O3 from 25 to 73 ppb resulted in a 25% yield reduction in treatments with ambient temperature and well-watered soil. Drought reduced the impact of O3 on light-saturated photosynthesis, grain mass, total aboveground biomass and grain concentrations of K, Ca, Mg, Mo. In contrast, concentrations of K and Ca increased to a larger extent when O3 stress was combined with elevated temperature. Grain concentrations of N, Ca and Zn were closely and negatively related to grain yield regardless of O3, heat and drought stress, likely explained by the reduction in grain filling period, with starch accumulation reduced to a larger extent than that of these elements. P, K, Mg, Mn, Mo concentrations were weakly related to grain yield, but were clearly altered by environmental stress. The modifying effect of water availability is crucial to include in assessments of O3 impacts on global food production in relation to climate change, considering effects on wheat yield variables and grain nutrient concentrations.
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| 8. |
- Karlsson, Per Erik, et al.
(författare)
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The vulnerability of northern European vegetation to ozone damage in a changing climate An assessment based on current knowledge
- 2021
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The potential vulnerability of vegetation at northern latitudes to ozone damage was assessed based on current knowledge with regard to air ozone concentrations and leaf ozone uptake as well as to plant traits affecting ozone tolerance. The focus was on the northern European arctic, alpine and northern boreal vegetation zones, with a special focus on high-altitude vegetation. In particular, we analysed if there are increasing risks for ozone impacts on northern vegetation due to high spring ozone concentrations in relation to climate change induced shifts such as e.g. an earlier start of the growing season. The ozone concentrations in these regions are characterized by the influence of a combination of conditions caused by high latitudes and high altitudes. Ozone concentrations increase with altitude and the difference in ozone concentrations between day and night are smaller at high-altitude and high-latitude sites. Summer periods with long daylight conditions potentially promote the leaf ozone uptake through the open stomata. The aims of this report were: • To assess the current state of knowledge regarding the potential vulnerability of far northern vegetation to ozone damage, today and in the future • To provide advice for policy implications regarding necessary ozone precursor emission abatement • To provide advice for future research and monitoring of ozone impacts on the vegetation at northern latitudes Ongoing environmental changes affecting far northern latitude ecosystems were reviewed. Current and novel methods were described for how to estimate the time of year during which the ozone exposure for vegetation should be accumulated. Time trends for ozone concentrations at northern latitudes were analysed. Ozone episodes with high concentrations at far northern latitudes were described. Source attributions of northern ozone concentrations were analysed. Environmental conditions at far northern latitudes that might be important for ozone damage were evaluated. Plant traits that can influence the ozone vulnerability were discussed. Current experimental results for ozone injury on northern plant species were evaluated. Future scenarios for ozone impact on northern vegetation were discussed. Some important results from the analyses are described below. At high altitudes and high latitudes, the ozone concentrations are relatively similar during day- and night-time. Furthermore, at high latitudes, the long daylight duration during the summer has the potential to increase the duration of the daily period with plant gas exchange and leaf ozone uptake. Therefore, the absorption of ozone through the stomata may potentially be higher at northern latitudes. However, measurements of light intensity and quality at northern sites in combination with a simple calculation example illustrated that this probably was not the case, since the potential added ozone uptake in the early morning and late evening at northern sites may be cancelled out by a lower ozone uptake in the middle of the day, as compared to southern sites. Both data on budburst and data on ecosystem CO2 exchange as well as meteorological observations show that there has been a development towards an earlier start of the growing season during the year, with approximately 0.5 – 1 day per year. Thus, there is clear evidence for an earlier start of the growing season, which is likely to continue. However, the timing of the spring ozone maximum is also shifted towards earlier in the year. There is presently no evidence for an increasing overlap between the growing season and the ozone peak. Despite this, there is a potential for increased ozone uptake to vegetation in spring due to the earlier growing start of vegetation and increased uptake of ozone to vegetation in May. The impact of this on the accumulated phytotoxic ozone dose for northern vegetation needs to be investigated further. The overall conclusions about the present and near future ozone vulnerability of northern vegetation were: • There remain uncertainties regarding to what extent northern vegetation is affected by ozone exposure. • According to current knowledge, we could not find evidence that expected changes in ozone concentrations and climate would make the northern arctic, alpine and subalpine vegetation substantially more vulnerable to ozone than other types of European vegetation. • The risk of significant and lasting negative impact of the current exposure to ozone on northern boreal forests is most likely not greater than for boreonemoral and nemoral forests in southern Fennoscandia. • However, peak ozone concentrations occurring in spring and early summer may affect vegetation at northern latitudes in Fennoscandia since the start of the growing season in the future may occur earlier during the year. The policy implications that can be derived from these conclusions were: • The current state of knowledge implies that ecosystems in the far north are not more susceptible to ozone than vegetation in other parts of Europe. Hence, we cannot advocate for a stronger reduction of ozone precursors emissions based exclusively on the ozone sensitivity of vegetation in the far north. • Policies designed to reduce emissions of ozone precursors to protect vegetation in other parts of Europe as well as in the entire northern hemisphere are likely to suffice to protect vegetation in northern Fennoscandia. There are important remaining knowledge gaps. Our conclusions are based on important, but limited observations. Experimental evidence from investigations specifically designed to study ozone sensitivity of high-altitude vegetation in northern Europe are to a large extent lacking. It is recommended that further experimental research is undertaken to directly compare the ozone sensitivity of plants of high-latitude/high-altitude origin with that of plants (species, genotypes) representative of regions of the southern part of the Nordic region. This research should include the characteristics of the high-latitude climate and other conditions. A specific research question is if the new ozone critical levels for European vegetation based on PODYSPEC (Mapping Manual, 2017) are correct, both regarding calculation methodology as well as impact assessments? In particular, there is a lack of information about the degree of stomata closure during nights in high-latitude area plants. This is important for the modelling of ozone uptake (dry deposition) in these areas and requires coordinated measurement campaigns in close cooperation with modelers. Further research questions may be related to the future development of the northern regions – e.g. oil and gas extraction including flaring, shipping, more tourism and climate change – how will that affect the ozone exposure of in the northern vegetation? Do future ozone precursor emission scenarios describe this correctly? Will warm and dry summers like 2018 become more frequent in connection with climate change, and how will this affect ozone impacts on vegetation? There are currently very few, long term ozone monitoring stations in the arctic and alpine vegetation zones, in particular at high altitudes. Given the expected increase in anthropogenic activities in these areas in combination with climate change, it is strongly recommended to increase the number of high-altitude ozone monitoring sites in these regions.
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| 9. |
- Mills, Gina, 1959, et al.
(författare)
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Closing the global ozone yield gap: Quantification and cobenefits for multistress tolerance
- 2018
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 24:10, s. 4869-4893
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Tidskriftsartikel (refereegranskat)abstract
- Increasing both crop productivity and the tolerance of crops to abiotic and biotic stresses is a major challenge for global food security in our rapidly changing climate. For the first time, we show how the spatial variation and severity of tropospheric ozone effects on yield compare with effects of other stresses on a global scale, and discuss mitigating actions against the negative effects of ozone. We show that the sensitivity to ozone declines in the order soybean>wheat>maize>rice, with genotypic variation in response being most pronounced for soybean and rice. Based on stomatal uptake, we estimate that ozone (mean of 2010–2012) reduces global yield annually by 12.4%, 7.1%, 4.4% and 6.1% for soybean, wheat, rice and maize, respectively (the “ozone yield gaps”), adding up to 227Tg of lost yield. Our modelling shows that the highest ozone-induced production losses for soybean are in North and South America whilst for wheat they are in India and China, for rice in parts of India, Bangladesh, China and Indonesia, and for maize in China and the United States. Crucially, we also show that the same areas are often also at risk of high losses from pests and diseases, heat stress and to a lesser extent aridity and nutrient stress. In a solution-focussed analysis of these results, we provide a crop ideotype with tolerance of multiple stresses (including ozone) and describe how ozone effects could be included in crop breeding programmes. We also discuss altered crop management approaches that could be applied to reduce ozone impacts in the shorter term. Given the severity of ozone effects on staple food crops in areas of the world that are also challenged by other stresses, we recommend increased attention to the benefits that could be gained from addressing the ozone yield gap.
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| 10. |
- Mills, Gina, 1959, et al.
(författare)
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New stomatal flux-based critical levels for ozone effects on vegetation
- 2011
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Ingår i: Atmospheric Environment. - : Elsevier BV. - 1873-2844 .- 1352-2310. ; 45:28, s. 5064-5068
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Tidskriftsartikel (refereegranskat)abstract
- The critical levels for ozone effects on vegetation have been reviewed and revised by the LRTAP Convention. Eight new or revised critical levels based on the accumulated stomatal flux of ozone (POD gamma, the Phytotoxic Ozone Dose above a threshold flux of Y nmol m(-2) PLA s(-1), where PLA is the projected leaf area) have been agreed. For each receptor, data were combined from experiments conducted under naturally fluctuating environmental conditions in 2-4 countries, resulting in linear dose response relationships with response variables specific to each receptor (r(2) = 0.49-0.87, p
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