Effects of various meteorological conditions and spatial emissionresolutions on the ozone concentration and ROG/NO&amp;lt;sub&amp;gt;x&amp;lt;/sub&amp;gt; limitationin the Milan area (I)

Baertsch-Ritter, N; Keller, Johannes; Dommen, Josef; Prévôt, Andrê S. H.

doi:10.5194/acp-4-423-2004

Cited by 69 publications

(30 citation statements)

References 30 publications

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“…High temperatures are usually associated aT 2 : square of the afternoon mean temperature ( • C 2 ) aMR: afternoon water vapour mixing ratio (g/kg) mRad: morning global radiation (W/m 2 ) aRad: afternoon global radiation (W/m 2 ) ndF: number of days after a frontal passage dTp: vertical gradient of potential temperature in the afternoon ( • C) aWspeed: afternoon averaged wind speed (m/s) Precip: occurrence/absence of precipitation wd: day of the week (weekday or weekend) (+)/(-) means that ozone is enhanced/reduced for higher values of temperature, global radiation, water vapour mixing ratio or wind speed Precip (+), wd (+), dTp (+): enhanced ozone for days with precipitation, for weekends and for instability, respectively ndF (+/-): increased/decreased ozone on the following days after a frontal passage with high radiation and stagnation of the air masses, and both the biogenic emissions and evaporative emissions of anthropogenic VOCs increase at high temperatures. In addition, the enhanced thermal decomposition of peroxyacyl nitrates (PANs) at high temperatures yields higher ozone production, as pointed out in some model studies (Sillman and Samson, 1995;Vogel et al, 1999;Baertsch-Ritter et al, 2004). As expected we found a positive correlation between global radiation and the ozone concentrations during the warm seasons, as the photolysis of NO 2 and other compounds like O 3 , carbonyls and HONO leads to the formation of radicals with subsequent involvement in ozone production.…”

Section: Resultssupporting

confidence: 66%

Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

et al. 2005

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Abstract. An Analysis of Covariance (ANCOVA) was used to derive the influence of the meteorological variability on the daily maximum ozone concentrations at 12 low-elevation sites north of the Alps in Switzerland during the four seasons in the 1992-2002 period. The afternoon temperature and the morning global radiation were the variables that accounted for most of the meteorological variability in summer and spring, while other variables that can be related to vertical mixing and dilution of primary pollutants (afternoon global radiation, wind speed, stability or day of the week) were more significant in winter. In addition, the number of days after a frontal passage was important to account for ozone build-up in summer and ozone destruction in winter. The statistical model proved to be a robust tool for reducing the impact of the meteorological variability on the ozone concentrations. The explained variance of the model, averaged over all stations, ranged from 60.2% in winter to 71.9% in autumn. The year-to-year variability of the seasonal medians of daily ozone maxima was reduced by 85% in winter, 60% in summer, and 50% in autumn and spring after the meteorological adjustment. For most stations, no significantly negative trends (at the 95% confidence level) of the summer medians of daily O 3 or O x (O 3 +NO 2 ) maxima were found despite the significant reduction in the precursor emissions in Central Europe. However, significant downward trends in the summer 90th percentiles of daily O x maxima were observed at 6 sites in the region around Zürich (on average −0.73 ppb yr −1 for those sites). The lower effect of the titration by NO as a consequence of the reduced emissions could partially explain the significantly positive O 3 trends in the cold seasons (on average 0.69 ppb yr −1 in winter and 0.58 ppb yr −1 in autumn). The increase of O x found for most stations in autumn (on average 0.23 ppb yr −1 ) and winter (on average 0.39 ppb yr −1 ) could be due to increasing European background ozone levCorrespondence to: A. S. H. Prévôt (andre.prevot@psi.ch) els, in agreement with other studies. The statistical model was also able to explain the very high ozone concentrations in summer 2003, the warmest summer in Switzerland for at least ∼150 years. On average, the measured daily ozone maximum was 15 ppb (nearly 29%) higher than in the reference period summer 1992-2002, corresponding to an excess of 5 standard deviations of the summer means of daily ozone maxima in that period.

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Section: Resultssupporting

confidence: 66%

Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

et al. 2005

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“…11). The main driver of enhanced ozone production (excluding temperature-driven emission changes) due to a temperature increase is peroxyacetyl nitrate (PAN) (including similar compounds) chemistry (Baertsch-Ritter et al, 2004;Dawson et al, 2007;Pusede et al, 2015). Those studies explain that PAN can serve as NO x and a radical reservoir, and redistribute them away from the large emission areas (e.g., cities, power plants) to more remote, rural ones (by thermally decomposing back to NO 2 and radicals).…”

Section: Temperaturementioning

confidence: 99%

“…On the other hand, it is known that surface ozone has a high positive correlation with temperature (Sillman and Samson, 1995;Pusede et al, 2015). As a result, temperature has been used in several studies (Neftel et al, 2002;Baertsch-Ritter et al, 2004;Bloomer et al, 2009) as a surrogate to indirectly assess surface ozone production via the ozone-temperature correlation. However, so far, the use of the ozone-temperature correlation was only applied locally for individual stations and not at a greater regional scale.…”

Section: Introductionmentioning

confidence: 99%

Low modeled ozone production suggests underestimation of precursor emissions (especially NO<sub><i>x</i></sub>) in Europe

et al. 2018

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Abstract. High surface ozone concentrations, which usually occur when photochemical ozone production takes place, pose a great risk to human health and vegetation. Air quality models are often used by policy makers as tools for the development of ozone mitigation strategies. However, the modeled ozone production is often not or not enough evaluated in many ozone modeling studies. The focus of this work is to evaluate the modeled ozone production in Europe indirectly, with the use of the ozone-temperature correlation for the summer of 2010 and to analyze its sensitivity to precursor emissions and meteorology by using the regional air quality model, the Comprehensive Air Quality Model with Extensions (CAMx). The results show that the model significantly underestimates the observed high afternoon surface ozone mixing ratios (≥ 60 ppb) by 10-20 ppb and overestimates the lower ones (< 40 ppb) by 5-15 ppb, resulting in a misleading good agreement with the observations for average ozone. The model also underestimates the ozone-temperature regression slope by about a factor of 2 for most of the measurement stations. To investigate the impact of emissions, four scenarios were tested: (i) increased volatile organic compound (VOC) emissions by a factor of 1.5 and 2 for the anthropogenic and biogenic VOC emissions, respectively, (ii) increased nitrogen oxide (NO x ) emissions by a factor of 2, (iii) a combination of the first two scenarios and (iv) increased trafficonly NO x emissions by a factor of 4. For southern, eastern, and central (except the Benelux area) Europe, doubling NO x emissions seems to be the most efficient scenario to reduce the underestimation of the observed high ozone mixing ratios without significant degradation of the model performance for the lower ozone mixing ratios. The model performance for ozone-temperature correlation is also better when NO x emissions are doubled. In the Benelux area, however, the third scenario (where both NO x and VOC emissions are increased) leads to a better model performance. Although increasing only the traffic NO x emissions by a factor of 4 gave very similar results to the doubling of all NO x emissions, the first scenario is more consistent with the uncertainties reported by other studies than the latter, suggesting that high uncertainties in NO x emissions might originate mainly from the road-transport sector rather than from other sectors. The impact of meteorology was examined with three sensitivity tests: (i) increased surface temperature by 4 • C, (ii) reduced wind speed by 50 % and (iii) doubled wind speed. The first two scenarios led to a consistent increase in all surface ozone mixing ratios, thus improving the model performance for the high ozone values but significantly degrading it for the low ozone values, while the third scenario had exactly the opposite effects. Overall, the modeled ozone is predicted to be more sensitive to its precursor emissions (especially traffic NO x ) and therefore their uncertainties, which seem to be responsible for the model un...

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“…VOC reactivity was calculated as the product of the VOC's number density and its rate constant against the hydroxyl radical ( Atkinson, 1997;Seinfeld and Pandis, 2006). Summer annual averages for total VOC reactivity were calculated as the sum of all VOC reactivity ( k i [VOC i ]) in units of inverse seconds.…”

Section: O 3 No X and Voc Analysesmentioning

confidence: 99%

The impacts of precursor reduction and meteorology on ground-level ozone in the Greater Toronto Area

et al. 2014

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Abstract. Tropospheric ozone (O 3 ) is a major component of photochemical smog and is a known human health hazard, as well as a damaging factor for vegetation. Its precursor compounds, nitrogen oxides (NO x ) and volatile organic compounds (VOCs), have a variety of anthropogenic and biogenic sources and exhibit non-linear effects on ozone production. As an update to previous studies on ground-level ozone in the Greater Toronto Area (GTA), we present an analysis of NO 2 , VOC and O 3 data from federal and provincial governmental monitoring sites in the GTA from 2000 to 2012. We show that, over the study period, summertime 24 h VOC reactivity and NO 2 midday (11:00-15:00) concentrations at all sites decreased significantly; since 2000, all sites experienced a decrease in NO 2 of 28-62 % and in measured VOC reactivity of at least 53-71 %. Comparing 2002Comparing -2003Comparing to 2011Comparing -2012, the summed reactivity of OH towards NO 2 and a suite of measured VOCs decreased from 8.6 to 4.6 s −1 . Ratios of reactive VOC pairs indicate that the effective OH concentration experienced by primary pollutants in the GTA has increased significantly over the study period. Despite the continuous decrease in precursor levels, ozone concentrations are not following the same pattern at all stations; it was found that the Canada-wide Standard for ozone continues to be exceeded at all monitoring stations. Additionally, while the years 2008-2011 had consistently lower ozone levels than previous years, 2012 experienced one of the highest recorded summertime ozone concentrations and a large number of smog episodes. We demonstrate that these high ozone observations in 2012 may be a result of the number of days with high solar radiation, the number of stagnant periods and the transport of high ozone levels from upwind regions.

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Effects of various meteorological conditions and spatial emissionresolutions on the ozone concentration and ROG/NO<sub>x</sub> limitationin the Milan area (I)

Cited by 69 publications

References 30 publications

Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

Low modeled ozone production suggests underestimation of precursor emissions (especially NO<sub><i>x</i></sub>) in Europe

The impacts of precursor reduction and meteorology on ground-level ozone in the Greater Toronto Area

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Effects of various meteorological conditions and spatial emissionresolutions on the ozone concentration and ROG/NO&lt;sub&gt;x&lt;/sub&gt; limitationin the Milan area (I)

Cited by 69 publications

References 30 publications

Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

Changes of daily surface ozone maxima in Switzerland in all seasons from 1992 to 2002 and discussion of summer 2003

Low modeled ozone production suggests underestimation of precursor emissions (especially NO&lt;sub&gt;&lt;i&gt;x&lt;/i&gt;&lt;/sub&gt;) in Europe

The impacts of precursor reduction and meteorology on ground-level ozone in the Greater Toronto Area

Contact Info

Product

Resources

About

Effects of various meteorological conditions and spatial emissionresolutions on the ozone concentration and ROG/NO<sub>x</sub> limitationin the Milan area (I)

Low modeled ozone production suggests underestimation of precursor emissions (especially NO<sub><i>x</i></sub>) in Europe