Age‐dependent increase in α‐tocopherol and phytosterols in maize leaves exposed to elevated ozone pollution

Air pollution and heat events present two major health risks, both already independently posing a significant threat to human health and life. High levels of ground-level ozone (O3) and air temperature often coincide due to the underlying physical relationships between both variables. The most severe health outcome is in general associated with the co-occurrence of both hazards (e.g. Hertig et al. 2020), since concurrent elevated levels of temperature and ozone concentrations represent a twofold exposure and can lead to a risk beyond the sum of the individual effects. Consequently, in the current contribution, a compound approach considering both hazards simultaneously as so-called ozone-temperature (o-t-)events is chosen by jointly analyzing elevated ground-level ozone concentrations and air temperature levels in Europe.Previous studies already point to the fact that the relationship of underlying synoptic and meteorological drivers with one or both of these health stressors as well as the correlation between both variables vary with the location of sites and seasons (e.g. Otero et al. 2016; Jahn, Hertig 2020). Therefore, a hierarchical clustering analysis is applied to objectively divide the study domain in regions of homogeneous, similar ground-level ozone and temperature characteristics (o-t-regions). Statistical models to assess the synoptic and large-scale meteorological mechanisms which represent main drivers of concurrent o-t-events are developed for each identified o-t-region.Compound elevated ozone concentration and air temperature events are expected to become more frequent due to climate change in many parts of Europe (e.g. Jahn, Hertig 2020; Hertig 2020). Statistical projections of potential frequency shifts of compound o-t-events until the end of the twenty-first century are assessed using the output of Earth System Models (ESMs) from the sixth phase of the Coupled Model Intercomparison Project (CMIP6).Hertig, E. (2020) Health-relevant ground-level ozone and temperature events under future climate change using the example of Bavaria, Southern Germany. Air Qual. Atmos. Health. doi: 10.1007/s11869-020-00811-zHertig, E., Russo, A., Trigo, R. (2020) Heat and ozone pollution waves in Central and South Europe- characteristics, weather types, and association with mortality. Atmosphere. doi: 10.3390/atmos11121271Jahn, S., Hertig, E. (2020) Modeling and projecting health&#8208;relevant combined ozone and temperature events in present and future Central European climate. Air Qual. Atmos. Health. doi: 10.1007/s11869&#8208;020&#8208;009610Otero N., Sillmann J., Schnell J.L., Rust H.W., Butler T. (2016) Synoptic and meteorological drivers of extreme ozone concentrations over Europe. Environ Res Lett. doi: 10.1088/ 1748-9326/11/2/024005

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Ozone reservoir layers in a coastal environment – a case study in Southern Taiwan

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-10-1719-2010 ◽

2010 ◽

Vol 10 (1) ◽

pp. 1719-1754

Author(s):

C.-H. Lin ◽

Y.-L. Wu ◽

C.-H. Lai

Keyword(s):

Ozone Concentration ◽

Surface Ozone ◽

Mixing Layer ◽

Ozone Pollution ◽

Ozone Concentrations ◽

Elevated Ozone ◽

Mountain Site ◽

Southern Taiwan ◽

Ozone Episode

Abstract. The air layer between the nocturnal boundary layer and the top of the daily mixing layer in an ozone-polluted area is known to serve as an ozone reservoir since the ozone that is produced in the previous daytime mixing layer can be well preserved throughout the night in the air layer. Ozone reservoir layers are capable of enhancing surface ozone accumulation on the following day. However, our knowledge of the characteristics of ozone reservoir layers and their effects on the daily ozone accumulations is limited. In this work, ozone reservoir layers were experimentally investigated at a coastal, near-mountain site in Southern Taiwan, 30 km away from the coastlines. Tethered ozone soundings were performed to obtain vertical profiles of ozone and meteorological variables during a four-day ozone episode in November 2006. Observation-based methods are adopted to evaluate the influences of the ozone reservoir layers on the surface ozone accumulation during the four-day ozone episode. Ozone reservoir layers were found to develop every evening with a depth of 1200–1400 m. Ozone concentrations within the reservoir layers reached over 140 parts per billion (ppb). From each evening to midnight, the size of the ozone reservoir layer and the ozone concentration inside dramatically changed. As a result, a concentrated, elevated ozone reservoir layer formed with a depth of 400 m at 800–1200 m every midnight. For the rest of each night, the elevated ozone reservoir layer gradually descended until it reached 500–900 m in the next morning. Local circulations and nocturnal subsidence are responsible for the observed evolution. The ozone concentration at the study site was maximal at 15:00–17:00 LT daily because of the addition of the daily produced ozone on the preceding day. Hourly downward mixing ozone concentrations due to the ozone reservoir layers can be as high as 35–45 ppb/h in the late morning. The contribution of the ozone carried over from the preceding day can be 75–85 ppb, which contributes over 50% to the daily ozone pollution as compared with ozone produced on the study day.

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Ozone reservoir layers in a coastal environment – a case study in southern Taiwan

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-4439-2010 ◽

2010 ◽

Vol 10 (9) ◽

pp. 4439-4452 ◽

Cited By ~ 4

Author(s):

C.-H. Lin ◽

Y.-L. Wu ◽

C.-H. Lai

Keyword(s):

Ozone Concentration ◽

Surface Ozone ◽

Mixing Layer ◽

Ozone Pollution ◽

Elevated Ozone ◽

Rate Of Increase ◽

Southern Taiwan ◽

Marine Air ◽

Ozone Episode

Abstract. The air layer between the nocturnal boundary layer and the top of the daily mixing layer in an ozone-polluted area is known to serve as an ozone reservoir since the ozone that is produced in the mixing layer on the preceding day is effectively preserved throughout the night in the air layer. Ozone reservoir layers existing at night can enhance the accumulation of surface ozone on the following day. However, our knowledge of the characteristics of ozone reservoir layers and their effects on the daily ozone accumulations is limited. In this work, ozone reservoir layers were experimentally investigated at a coastal, near-mountain site in southern Taiwan, 30 km away from the coastline. Tethered ozone soundings were performed to obtain vertical profiles of ozone and meteorological variables during a four-day ozone episode in November 2006. Observation-based methods are adopted to evaluate the effects of the ozone reservoir layers on the surface ozone accumulation during the four-day ozone episode. Ozone reservoir layers were found to develop every evening with a depth of 1200–1400 m. Ozone concentrations within the reservoir layers reached over 140 parts per billion (ppb). From each evening to midnight, the size of the ozone reservoir layer and the ozone concentration inside dramatically changed. As a result, a concentrated, elevated ozone reservoir layer formed with a depth of 400 m at 800–1200 m every midnight. For the rest of each night, the elevated ozone reservoir layer gradually descended until it reached 500–900 m in the next morning. The observed ozone reservoir layer is formed by the invasion of a cool, marine air mass into a relatively warm, ozone-rich mixing layer in the evening. The descending is related to nocturnal coastal subsidence as well. The ozone concentration at the study site was maximal at 15:00–17:00 LT daily because of the addition of the daily produced ozone on the preceding day. The rate of increase of surface ozone concentration due to the downward mixing of the ozone in the ozone reservoir layers can be as high as 12–24 ppb/h in the late morning. The contribution of the ozone carried over from the preceding day can be 60–85 ppb, which contributes over 50% to the daily ozone pollution as compared with ozone produced on the study day.

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Age-dependent increase in α-tocopherol and phytosterols in maize leaves exposed to elevated ozone pollution

10.1101/2020.11.09.360644 ◽

2020 ◽

Author(s):

Jessica M. Wedow ◽

Charles H. Burroughs ◽

Lorena Rios Acosta ◽

Andrew D.B. Leakey ◽

Elizabeth A. Ainsworth

Keyword(s):

Crop Production ◽

Inbred Lines ◽

Air Pollutant ◽

Ozone Exposure ◽

Metabolic Responses ◽

Hybrid Line ◽

Elevated Ozone ◽

Significant Difference ◽

Age Dependent ◽

Ozone Stress

AbstractTropospheric ozone is a major air pollutant that significantly damages crop production around the world. Crop metabolic responses to rising chronic ozone stress have not been well-studied in the field, especially in C4 crops. In this study, we investigated the metabolomic profile of leaves from two diverse maize (Zea mays) inbred lines and the hybrid cross during exposure to season-long elevated ozone (~100 nL L−1) in the field using free air concentration enrichment (FACE) to identify key biochemical responses of maize to elevated ozone. Senescence, measured by loss of chlorophyll content, was accelerated in the hybrid line, B73 x Mo17, but not in either inbred line (B73 or Mo17). Untargeted metabolomic profiling further revealed that inbred and hybrid lines of maize differed in metabolic responses to ozone. A significant difference in the metabolite profile of hybrid leaves exposed to elevated ozone occurred as leaves aged, but no age-dependent difference in leaf metabolite profiles between ozone conditions was measured in the inbred lines. Phytosterols and α-tocopherol levels increased in B73 x Mo17 leaves as they aged, and to a significantly greater degree in elevated ozone stress. These metabolites are involved in membrane stabilization and chloroplast reactive oxygen species (ROS) quenching. The hybrid line also showed significant yield loss at elevated ozone, which the inbred lines did not. This suggests that the hybrid maize line was more sensitive to ozone exposure than the inbred lines, and up-regulated metabolic pathways to stabilize membranes and quench ROS in response to chronic ozone stress.

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Effects of Hyperoxia on Lung Utrastructure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067121 ◽

1970 ◽

Vol 28 ◽

pp. 26-27

Author(s):

Gladys Harrison

Keyword(s):

Central Nervous System ◽

Nervous System ◽

Light Microscopy ◽

Oxygen Effects ◽

Age Dependent ◽

The Central Nervous System ◽

The Subject ◽

Space Age ◽

Alveolar Septa ◽

Extensive Damage

With the advent of the space age and the need to determine the requirements for a space cabin atmosphere, oxygen effects came into increased importance, even though these effects have been the subject of continuous research for many years. In fact, Priestly initiated oxygen research when in 1775 he published his results of isolating oxygen and described the effects of breathing it on himself and two mice, the only creatures to have had the “privilege” of breathing this “pure air”.Early studies had demonstrated the central nervous system effects at pressures above one atmosphere. Light microscopy revealed extensive damage to the lungs at one atmosphere. These changes which included perivascular and peribronchial edema, focal hemorrhage, rupture of the alveolar septa, and widespread edema, resulted in death of the animal in less than one week. The severity of the symptoms differed between species and was age dependent, with young animals being more resistant.

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