Seasonal dependence of the oxidation capacity of the city of Santiago de Chile

Elshorbany, Yasin; Kleffmann, Jörg; Kurtenbach, R.; Lissi, E. A.; Rubio, Marı́a A.; Villena, Guillermo Lohmann; Gramsch, E.; Rickard, Andrew R.; Pilling, Michael J.; Wiesen, Peter

doi:10.1016/j.atmosenv.2009.08.036

Cited by 78 publications

(75 citation statements)

References 25 publications

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“…This value (1.8·10 6 molecules cm −3 ) is on the same order of magnitude as values determined outdoors in the urban scenario (32). A quasiphotostationary state (quasi-PSS) model (33,34) was also implemented to assist in our assessment of the main sources determining the production of OH radicals indoors. Fig.…”

Section: Resultsmentioning

confidence: 86%

“…According to Elshorbany et al (33), the reaction between OH and VOC is typically OH-neutral at high NOx greater than a few hundred ppt (in this study, NOx levels were on the order of tens of ppb); that is, any OH that is consumed by a reaction with VOCs is recovered by recycling. Additionally, it has been shown that the PSS approach reproduces an accurate OH concentration at a high NOx level (above 10 ppb, as is the case in this study) in several environments and that below 10 ppb, there is overestimation of up to a factor of 4 (34).…”

Section: Displays [Oh] Pss1 Values Also Considering the Ozonolysis Omentioning

confidence: 99%

See 1 more Smart Citation

Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid

Álvarez

Amedro

Afif

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

177

234

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The hydroxyl (OH) radical is the most important oxidant in the atmosphere since it controls its self-oxidizing capacity. The main sources of OH radicals are the photolysis of ozone and the photolysis of nitrous acid (HONO). Due to the attenuation of solar radiation in the indoor environment, the possibility of OH formation through photolytic pathways indoors has been ignored up to now. In the indoor air, the ozonolysis of alkenes has been suggested as an alternative route of OH formation. Models and indirect measurements performed up to now according to this hypothesis suggest concentrations of OH radicals on the order of 10 4 –10 5 molecules per cubic centimeter. Here, we present direct measurements of significant amounts of OH radicals of up to 1.8⋅10 6 molecules per cubic centimeter during an experimental campaign carried out in a school classroom in Marseille. This concentration is on the same order of magnitude of outdoor OH levels in the urban scenario. We also show that photolysis of HONO is an important source of OH radicals indoors under certain conditions (i.e., direct solar irradiation inside the room). Additionally, the OH concentrations were found to follow a linear dependence with the product J(HONO)⋅[HONO]. This was also supported by using a simple quasiphotostationary state model on the OH radical budget. These findings force a change in our understanding of indoor air quality because the reactivity linked to OH would involve formation of secondary species through chemical reactions that are potentially more hazardous than the primary pollutants in the indoor air.

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Section: Resultsmentioning

confidence: 86%

Section: Displays [Oh] Pss1 Values Also Considering the Ozonolysis Omentioning

confidence: 99%

Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid

Álvarez

Amedro

Afif

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

177

234

View full text Add to dashboard Cite

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“…Kleffmann and Wiesen, 2008) and urban conditions (e.g. Elshorbany et al, 2009aElshorbany et al, , 2010a. Furthermore, Villena et al (2011a) showed that the HONO/NO x ratio and its daytime maximum are independent of altitude.…”

Section: Y F Elshorbany Et Al: Impact Of Hono On Global Atmospherimentioning

confidence: 99%

“…Recently, HONO photolysis was reported to contribute more strongly to daytime primary OH production than O 3 photolysis, both under urban and rural conditions (Elshorbany et al, 2009a;Sörgel et al, 2011a, respectively). It has been demonstrated that HONO photolysis can be a major OH initiation source under high NO x (e.g., Kleffmann et al, 2007;Elshorbany et al, 2009aElshorbany et al, , 2010aRen et al, 2006;Dusanter et al, 2009) as well as low NO x conditions (e.g., Kleffmann et al, 2005;Elshorbany et al, 2012, Sörgel et al, 2011a. OH radicals constitute the major oxidant of the atmosphere, initiating the removal of most reactive gases (i.e.…”

Section: Introductionmentioning

confidence: 99%

Impact of HONO on global atmospheric chemistry calculated with an empirical parameterization in the EMAC model

et al. 2012

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Abstract. The photolysis of HONO is important for the atmospheric HO x (OH + HO 2 ) radical budget and ozone formation, especially in polluted air. Nevertheless, owing to the incomplete knowledge of HONO sources, realistic HONO mechanisms have not yet been implemented in global models. We investigated measurement data sets from 15 field measurement campaigns conducted in different countries worldwide. It appears that the HONO/NO x ratio is a good proxy predictor for HONO mixing ratios under different atmospheric conditions. From the robust relationship between HONO and NO x , a representative mean HONO/NO x ratio of 0.02 has been derived. Using a global chemistry-climate model and employing this HONO/NO x ratio, realistic HONO levels are simulated, being about one order of magnitude higher than the reference calculations that only consider the reaction OH + NO → HONO. The resulting enhancement of HONO significantly impacts HO x levels and photo-oxidation products (e.g, O 3 , PAN), mainly in polluted regions. Furthermore, the relative enhancements in OH and secondary products are higher in winter than in summer, thus enhancing the oxidation capacity in polluted regions, especially in winter when other photolytic OH sources are of minor importance. Our results underscore the need to improve the understanding of HONO chemistry and its representation in atmospheric models.

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“…Nitrous acid (HONO) is an important precursor of the OH radical, which prominently controls the self-cleaning capacity of the troposphere (Alicke et al, 2003;Kleffmann et al, 2005;Acker et al, 2006;Monks et al, 2009;Elshorbany et al, 2010). The gas-phase reaction of NO with the OH radical (Stuhl and Niki, 1972;Pagsberg et al, 1997) mostly determines the daytime HONO concentration.…”

Section: Introductionmentioning

confidence: 99%

MAX-DOAS measurements of HONO slant column densities during the MAD-CAT campaign: inter-comparison, sensitivity studies on spectral analysis settings, and error budget

et al. 2017

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Abstract. In order to promote the development of the passive DOAS technique the Multi Axis DOAS -Comparison campaign for Aerosols and Trace gases (MAD-CAT) was held at the Max Planck Institute for Chemistry in Mainz, Germany, from June to October 2013. Here, we systematically compare the differential slant column densities (dSCDs) of nitrous acid (HONO) derived from measurements of seven different instruments. We also compare the tropospheric difference of SCDs (delta SCD) of HONO, namely the difference of the SCDs for the non-zenith observations and the zenith observation of the same elevation sequence. Different research groups analysed the spectra from their own instruments using their individual fit software. All the fit errors of HONO dSCDs from the instruments with cooled large-size detectors are mostly in the range of 0.1 to 0.3 × 10 15 molecules cm −2 for an integration time of 1 min. The fit error for the mini MAX-DOAS is around 0.7 × 10 15 molecules cm −2 . Although the HONO delta SCDs are normally smaller than 6 × 10 15 molecules cm −2 , consistent time series of HONO delta SCDs are retrieved from the measurements of different instruments. Both fits with a sequential Fraunhofer reference spectrum (FRS) and a daily noon FRS lead to similar consistency. Apart from the mini-MAX-DOAS, the systematic absolute differences of HONO delta SCDs between the instruments are smaller than 0.63 × 10 15 molecules cm −2 . The correlation coefficients are higher than 0.7 and the slopes of linear regressions deviate from unity by less than 16 % for the elevation angle of 1 • . The correlations decrease with an increase in elevation angle. All the participants also analysed synthetic spectra using the same baseline DOAS settings toPublished by Copernicus Publications on behalf of the European Geosciences Union. Y. Wang et al.: MAX-DOAS measurements of HONO slant column densitiesevaluate the systematic errors of HONO results from their respective fit programs. In general the errors are smaller than 0.3 × 10 15 molecules cm −2 , which is about half of the systematic difference between the real measurements.The differences of HONO delta SCDs retrieved in the selected three spectral ranges 335-361, 335-373 and 335-390 nm are considerable (up to 0.57 × 10 15 molecules cm −2 ) for both real measurements and synthetic spectra. We performed sensitivity studies to quantify the dominant systematic error sources and to find a recommended DOAS setting in the three spectral ranges. The results show that water vapour absorption, temperature and wavelength dependence of O 4 absorption, temperature dependence of Ring spectrum, and polynomial and intensity offset correction all together dominate the systematic errors. We recommend a fit range of 335-373 nm for HONO retrievals. In such fit range the overall systematic uncertainty is about 0.87 × 10 15 molecules cm −2 , much smaller than those in the other two ranges. The typical random uncertainty is estimated to be about 0.16 × 10 15 molecules cm −2 , which is only 25 % of the total syst...

show abstract

Seasonal dependence of the oxidation capacity of the city of Santiago de Chile

Cited by 78 publications

References 25 publications

Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid

Unexpectedly high indoor hydroxyl radical concentrations associated with nitrous acid

Impact of HONO on global atmospheric chemistry calculated with an empirical parameterization in the EMAC model

MAX-DOAS measurements of HONO slant column densities during the MAD-CAT campaign: inter-comparison, sensitivity studies on spectral analysis settings, and error budget

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