Changes in Nordic surface ozone episodes due to European emission reductions in the 1990s

We develop a statistical model to predict June–July–August (JJA) daily maximum 8-h average (MDA8) ozone concentrations in the eastern United States based on large-scale climate patterns during the previous spring. We find that anomalously high JJA ozone in the East is correlated with these springtime patterns: warm tropical Atlantic and cold northeast Pacific sea surface temperatures (SSTs), as well as positive sea level pressure (SLP) anomalies over Hawaii and negative SLP anomalies over the Atlantic and North America. We then develop a linear regression model to predict JJA MDA8 ozone from 1980 to 2013, using the identified SST and SLP patterns from the previous spring. The model explains ∼45% of the variability in JJA MDA8 ozone concentrations and ∼30% variability in the number of JJA ozone episodes (>70 ppbv) when averaged over the eastern United States. This seasonal predictability results from large-scale ocean–atmosphere interactions. Warm tropical Atlantic SSTs can trigger diabatic heating in the atmosphere and influence the extratropical climate through stationary wave propagation, leading to greater subsidence, less precipitation, and higher temperatures in the East, which increases surface ozone concentrations there. Cooler SSTs in the northeast Pacific are also associated with more summertime heatwaves and high ozone in the East. On average, models participating in the Atmospheric Model Intercomparison Project fail to capture the influence of this ocean–atmosphere interaction on temperatures in the eastern United States, implying that such models would have difficulty simulating the interannual variability of surface ozone in this region.

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High Surface Ozone Episodes at New Delhi, India

On a Sustainable Future of the Earth's Natural Resources ◽

10.1007/978-3-642-32917-3_26 ◽

2012 ◽

pp. 445-453 ◽

Cited By ~ 1

Author(s):

Nandita D. Ganguly ◽

Chris Tzanis

Keyword(s):

Surface Ozone ◽

High Surface ◽

New Delhi ◽

Ozone Episodes

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Decadal Trends and Variability in Intermountain West Surface Ozone near Oil and Gas Extraction Fields

10.5194/acp-2019-164 ◽

2019 ◽

Author(s):

Ying Zhou ◽

Huiting Mao ◽

Barkley C. Sive

Keyword(s):

Natural Gas ◽

National Park ◽

Oil And Gas ◽

Surface Ozone ◽

Gas Production ◽

Mitigation Strategies ◽

The Arctic ◽

Daily Maximum ◽

Intermountain West ◽

Emission Reductions

Abstract. Decadal trends in the annual fourth-highest daily maximum 8-hour average (A4DM8HA) ozone (O3) were studied over 2005–2015 for 13 rural/remote sites in the U.S. Intermountain West. No trends were observed in A4DM8HA O3 at two reference sites, which are located upwind of and thus minimally influenced by emissions from oil and natural gas (O&NG) basins. Trends, or a lack thereof, varied widely at other 11 sites in/near O&NG basins resulting from different controlling factors rather than a simplistic, uniform one. The decreasing trends at Mesa Verde (−0.76 ppbv/yr) and Canyonlands National Park (−0.54 ppbv/yr) were attributed to a 37 % decrease in natural gas production in the San Juan Basin and 35 % emission reductions in coal-fired electricity generation, respectively. The decreasing trend (−1.21 ppbv/yr) at Wind Cave National Park resulted from reduced solar radiation due to increasingly frequent precipitation weather. The lack of trends at remaining sites was likely caused by the increasing O&NG emissions and decreasing emissions from other activities. Wintertime O3 stagnant events were associated with the Arctic Oscillation (AO). Box model simulations suggested that both volatile organic compounds (VOCs) and nitrogen oxides emission reductions during negative AO years while VOC emission reductions alone in positive AO years could effectively mitigate high wintertime O3 within the O&NG basins. Our findings suggest that emissions from O&NG extraction likely played a significant role in shaping long-term trends in surface O3 near/within O&NG basins and hence warrant consideration in the design of efficient O3 mitigation strategies for the Intermountain West.

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Vegetation feedbacks during drought exacerbate ozone air pollution extremes in Europe

10.5194/egusphere-egu2020-12605 ◽

2020 ◽

Author(s):

Meiyun Lin ◽

Larry Horowitz ◽

Yuanyu Xie ◽

Fabien Paulot ◽

Sergey Malyshev ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Drought Stress ◽

Dry Deposition ◽

Surface Ozone ◽

Ozone Pollution ◽

Ozone Uptake ◽

Vegetation Feedbacks ◽

Ozone Episodes ◽

Pollution Episodes

This study highlights a previously under-appreciated &#8220;climate penalty&#8221; feedback mechanism - namely, substantial reductions of ozone uptake by water stressed vegetation &#8211; as a missing piece to the puzzle of why European ozone pollution episodes have not decreased as expected in recent decades, despite marked reductions in regional emissions of ozone precursors due to regulatory changes. The most extreme ozone pollution episodes are linked to heatwaves and droughts, which are increasing in frequency and intensity over Europe, with severe impacts on natural and human systems. Under drought stress, plants close their stomata to reduce water loss, consequently limiting the ozone uptake by vegetation (a component of dry deposition), leading to increased surface ozone concentrations. Such land-biosphere feedbacks are often overlooked in prior air quality projections, owing to a lack of process-based model formulations. Here, we use six decades of observations and Earth system model simulations (1960-2018) with an interactive dry deposition scheme to show that declining ozone removal by water-stressed vegetation in the warming climate exacerbate ozone air pollution over Europe. Incorporated into a dynamic vegetation land &#8211; atmospheric chemistry &#8211; climate model, the dry deposition scheme mechanistically describes the response of ozone deposition to atmospheric CO2&#160;concentration, canopy air vapor pressure deficit, and soil water availability. Our observational and modeling analyses reveal drought stress causing as much as 70% reductions in ozone removal by forests. Reduced ozone removal by water-stressed vegetation worsens peak ozone episodes during European mega-droughts, such as the 2003 event, offsetting much of the air quality improvements gained from regional emission controls. Accounting for vegetation feedbacks leads to a three-fold increase in high surface ozone events above 80 ppbv (8-hour average) and a 20% increase in the sensitivity of ozone pollution extremes (95th&#160;percentile) to increasing temperature. As the frequency of hot and dry summers is expected to increase in the coming decades, this ozone climate penalty could be severe and therefore needs to be considered when designing clean air policy in the European Union.&#160;Notes: This study is currently under review for possible publication in Nature Climate Change.&#160;

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Can we explain the trends in European ozone levels?

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-5957-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 5957-5985 ◽

Cited By ~ 5

Author(s):

J. E. Jonson ◽

D. Simpson ◽

H. Fagerli ◽

S. Solberg

Keyword(s):

North Atlantic ◽

Polar Region ◽

Surface Ozone ◽

Lateral Boundary ◽

Model Calculations ◽

The North ◽

Ozone Trends ◽

Ozone Precursor ◽

Ozone Episodes ◽

Ozone Levels

Abstract. Ozone levels in Europe are changing. Emissions of ozone precursors from Europe (NOx, CO and non-methane hydrocarbons) have been substantially reduced over the last 10–15 years, but changes in ozone levels can not be explained by changes in European emissions alone. In order to explain the European trends in ozone since 1990 the EMEP regional photochemistry model has been run for the the years 1990 and 1995–2002. The EMEP model is a regional model centered over Europe but the model domain also includes most of the North Atlantic and the polar region. Climatological ozone data are used as initial and lateral boundary concentrations. Model results are compared to measurements over this timespan of 12 years. Possible causes for the measured trends in European surface ozone have been investigated using model sensitivity runs perturbing emissions and lateral boundary concentrations. The observed ozone trends at many European sites are only partially reproduced by global or regional photochemistry models, and possible reasons for this are discussed. The increase in winter ozone partially and the decrease in the magnitude of high ozone episodes is attributed to the decrease in ozone precursor emissions since 1990 by the model. Furthermore, the model calculations indicate that the emission reductions has resulted in a marked decrease in summer ozone in major parts of Europe, and in particular in Germany. Such a trend in summer ozone is likely to be difficult to identify from the measurements because of large inter-annual variability.

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Spatial distribution and temporal trend of ozone pollution in China observed with the OMI satellite instrument, 2005–2017

10.5194/acp-2018-1246 ◽

2018 ◽

Author(s):

Lu Shen ◽

Daniel J. Jacob ◽

Xiong Liu ◽

Guanyu Huang ◽

Ke Li ◽

...

Keyword(s):

Surface Ozone ◽

Eastern China ◽

Ozone Pollution ◽

The North ◽

The Pacific ◽

Extreme Value Model ◽

The Individual ◽

Value Model ◽

Ozone Episodes ◽

Ozone Episode

Abstract. We use data from the new China Ministry of Ecology and Environment (MEE) network to show that OMI satellite observations of tropospheric ozone can successfully map the distribution of surface ozone pollution in China and the frequency of high-ozone episodes. After subtracting the Pacific background, OMI ozone enhancements over China can quantify mean summer afternoon surface ozone with a precision of 10.7 ppb and a spatial correlation coefficient R=0.73. Day-to-day correlations between OMI and the MEE ozone data are statistically significant but limited by noise in the individual OMI retrievals. OMI shows significantly higher values on surface ozone episode days (>82 ppb). An extreme value model can successfully predict the probability of surface ozone episodes from the daily OMI data. The 2005–2017 OMI record shows a 0.67 ppb a−1 increase in mean summer afternoon ozone in eastern China and an increasing frequency of ozone pollution episodes particularly in the north.

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An investigation on the origin of regional spring time ozone episodes in the Western Mediterranean and Central Europe

10.5194/acp-2016-615 ◽

2016 ◽

Author(s):

Pavlos Kalabokas ◽

Jens Hjorth ◽

Gilles Foret ◽

Gaëlle Dufour ◽

Maxim Eremenko ◽

...

Keyword(s):

Boundary Layer ◽

Central Europe ◽

Wind Velocity ◽

Geopotential Height ◽

Surface Ozone ◽

Western Mediterranean ◽

Specific Humidity ◽

Ozone Concentrations ◽

Ozone Episodes ◽

Vertical Wind Velocity

Abstract. For the identification of regional spring time ozone episodes, rural EMEP ozone measurements from countries surrounding the Western Mediterranean (Spain, France, Switzerland, Italy, Malta) have been examined with emphasis on periods of high ozone concentrations, according to the daily variation of the afternoon (12:00–18:00) ozone values. For two selected high ozone episodes in April and May 2008, composite NCEP/NCAR reanalysis maps of various meteorological parameters and/or their anomalies (geopotential height, specific humidity, vertical wind velocity omega, vector wind speed and temperature) at various tropospheric pressure levels have been examined together with the corresponding satellite IASI ozone measurements (at 3 and 10 km), CHIMERE simulations, vertical ozone soundings and HYSPLIT back trajectories. The results show that high ozone values are detected in several countries simultaneously over several days. Also, the examined spring ozone episodes over the Western Mediterranean and in Central Europe are linked to synoptic meteorological conditions very similar to those recently observed in summertime ozone episodes over the Eastern Mediterranean (Kalabokas et al., ACP, 2013; Doche et al., ACP, 2014; Kalabokas et al., TellusB, 2015), where the transport of tropospheric ozone-rich air masses through atmospheric subsidence influences significantly the boundary layer and surface ozone concentrations. In particular, the geographic areas with observed tropospheric subsidence seem to be the transition regions between high pressure and low pressure systems. Over these areas, strong gradients of geopotential height and temperature are observed, together with high positive omega vertical wind velocity (downward transport) and low specific humidity (dry conditions), at all examined pressure levels below the altitude of 500 hPa pressure level. During the surface ozone episodes IASI satellite measurements show extended areas of high ozone in the lower and upper troposphere over the low pressure system areas, adjacent to the anticyclones, which influence significantly the boundary layer and surface ozone concentrations within the anticyclones by subsidence and advection in addition to the photochemically produced ozone there, resulting in exceedances of the 60 ppb standard.

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The Response of surface ozone to climate change over the Eastern United States

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-9867-2007 ◽

2007 ◽

Vol 7 (4) ◽

pp. 9867-9897 ◽

Cited By ~ 3

Author(s):

P. N. Racherla ◽

P. J. Adams

Keyword(s):

Climate Change ◽

United States ◽

Surface Ozone ◽

Future Climate ◽

Future Climate Change ◽

Eastern United States ◽

Chemical Production ◽

Annual Average ◽

Mixing Ratios ◽

Ozone Episodes

Abstract. We examined the response of surface ozone to future climate change over the eastern United States by performing simulations corresponding to present (1990s) and future (2050s) climates using an integrated model of global climate, tropospheric gas-phase chemistry, and aerosols. A future climate has been imposed using ocean boundary conditions corresponding to the IPCC SRES A2 scenario for the 2050 s decade, resulting in an increase in the global annual-average surface air temperature by 1.7°C, with a 1.4°C increase over the surface layer of the eastern United States. Present-day anthropogenic emissions and CO2/CH4 mixing ratios have been used in both simulations while climate-sensitive natural emissions were allowed to vary with the simulated climate. There is practically zero change in the spatiotemporally averaged ozone mixing ratios predicted over the eastern United States. However, the severity and frequency of ozone episodes over the eastern United States increased due to future climate change, primarily as a result of increased ozone chemical production due to increased natural isoprene emissions. The 95th percentile ozone mixing ratio increased by 5 ppbv and the largest frequency increase occured in the 80–90 ppbv range. The most substantial and statistically significant (p-value <0.05) increases in episode frequency occurred over the southeast and midatlantic United States, largely as a result of 20% higher annual-average natural isoprene emissions. Increased chemical production and shorter average lifetime are consistent features of the predicted seasonal surface ozone response, with the former's magnitude for a location largely a function of increased natural isoprene emissions, and the latter largely due to faster dry deposition removal rates. Future climate change is also predicted to lengthen the ozone season over the eastern United States to include late spring and early fall. Significant interannual variability is observed in the frequency of ozone episodes and we find that it is necessary to utilize 5 years or more of simulation data in order to separate the effects of interannual variability and climate change on ozone episodes.

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European surface ozone in the extreme summer 2003

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-9003-2005 ◽

2005 ◽

Vol 5 (5) ◽

pp. 9003-9038 ◽

Cited By ~ 11

Author(s):

S. Solberg ◽

P. Coddeville ◽

C. Forster ◽

Ø. Hov ◽

Y. Orsolini ◽

...

Keyword(s):

Forest Fires ◽

Dispersion Model ◽

Surface Ozone ◽

Background Level ◽

Weather Conditions ◽

Anthropogenic Sources ◽

Ozone Formation ◽

Northern Latitudes ◽

Elevated Surface ◽

Ozone Episodes

Abstract. Measurements of ozone and other species from the European EMEP network in 2003 are presented. The European summer of 2003 was exceptionally warm and the surface ozone data for central Europe show the highest values since the end of the 1980s. The concentrations were particularly high in June and August 2003. In this paper we argue that a number of positive feedback effects between the weather conditions and ozone contributed to the elevated surface ozone. Firstly, direct measurements of isoprene as well as the increased temperature and solar radiation indicate that biogenic emissions in Europe were increased during summer 2003 with a potential for enhanced ozone formation. Secondly, we show that the anticyclonic conditions during the ozone episodes were accompanied by an extended residence time of air parcels in the atmospheric boundary layer, a low total ozone column and a reduced cloud cover, all favouring ozone formation. Thirdly, based on the Lagrangian dispersion model FLEXPART, we show that is very likely that extensive forest fires on the Iberian Peninsula, resulting from the drought and heat, contributed to the peak ozone values observed in North Europe in August. Additionally, forest fires in Siberia probably lead to an elevated background level of ozone and CO at northern latitudes during summer 2003 thereby increasing the level the peak ozone episodes sat on. Lastly, and most important, the heat wave presumably lead to less efficient ozone dry deposition due to stomata closure of the plants under drought stress. Due to climate change, situations like this may occur at a higher frequency in the future and may gradually overshadow the effect of reduced emissions from anthropogenic sources of VOC and NOx. This scenario also holds for secondary PM.

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