Hydroxyl and Peroxy Radical Chemistry in a Rural Area of Central Pennsylvania: Observations and Model Comparisons

Ren, Xinrong; Brune, William H.; Cantrell, C. A.; Edwards, George C.; Shirley, T.; Metcalf, A. R.; Lesher, R.

doi:10.1007/s10874-005-3651-7

Cited by 68 publications

(68 citation statements)

References 56 publications

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“…This method should work in an average sense. This method has been shown to give good results between measured and modeled HO x in other studies (Ren et al, 2005(Ren et al, , 2006.…”

Section: Models For Analysis Of the Measurementsmentioning

confidence: 62%

“…For instance we can test the expected balance between OH production and loss and the dependence of the HO 2 /OH ratio on controlling variables such as nitric oxide (NO). We have also shown that in some regions OH reactivity combined with a general knowledge of the VOC speciation is sufficient to model the observed OH and HO 2 with a fidelity that is as good as is obtained in field studies with more frequent measurements of speciated VOCs (Ren et al, 2005(Ren et al, , 2006. OH, HO 2 , OH reactivity, and other atmospheric constituents important for studying atmospheric oxidation were measured during the Mexico City Metropolitan Area 2003 (MCMA-2003) study, which was held in the MCMA during April 2003.…”

Section: Introductionmentioning

confidence: 65%

“…Fortunately, the OH reactivity measurement gives us information about the total amount of VOCs; all that is needed is information about the typical VOC speciation types throughout the day. We employ the same strategy for the MCMA-2003 study that we did for two other recent studies (Ren et al, 2005(Ren et al, , 2006. To get the VOC speciation type inputs to the model, the information from the measured OH reactivity was used along with the mean fractions of VOCs types combined from CENICA and three other sites.…”

Section: Models For Analysis Of the Measurementsmentioning

confidence: 99%

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Atmospheric oxidation in the Mexico City Metropolitan Area (MCMA) during April 2003

et al. 2006

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Abstract. The Mexico City Metropolitan Area (MCMA) study in April 2003 had measurements of many atmospheric constituents, including OH and HO 2 . It provided the first opportunity to examine atmospheric oxidation in a megacity in a developing country that has more pollution than typical U.S. and European cities. At midday, OH typically reached 0.35 pptv (∼7×10 6 cm −3 ), comparable to amounts observed in U.S. cities, but HO 2 reached 40 pptv, more than observed in most U.S. cities. The OH reactivity was also measured, even during the highly polluted morning rush hour. MCMA's OH reactivity was 25 s −1 during most of the day and 120 s −1 at morning rush hour, which was several times greater than has been measured in any U.S. city. Median measured and modeled OH and HO 2 agreed to within combined uncertainties, although for OH, the model exceeded the measurement by more than 30% during midday. OH production and loss, which were calculated from measurements, were in balance to within uncertainties, although production exceeded loss during morning rush hour. This imbalance has been observed in other cities. The HO 2 /OH ratio from measurements and steady-state analyses have essentially the same dependence on NO, except when NO was near 100 ppbv. This agreement is unlike other urban studies, in which HO 2 /OH ratio decreased much less than expected as NO increased. As a result of the active photochemistry in MCMA 2003, the median calculated ozone production from measured HO 2 reached 50 ppb h −1 , a much higher rate than observed in U.S. cities.

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“…This method should work in an average sense. This method has been shown to give good results between measured and modeled HO x in other studies (Ren et al, 2005(Ren et al, , 2006.…”

Section: Models For Analysis Of the Measurementsmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 65%

Section: Models For Analysis Of the Measurementsmentioning

confidence: 99%

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Atmospheric oxidation in the Mexico City Metropolitan Area (MCMA) during April 2003

et al. 2006

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“…Several field campaigns, including those in clean environments, have shown that the OH reactivity is dominated by oxygenated VOCs, for example carbonyl species and alcohols, rather than hydrocarbons (Lewis et al, 2005;Emmerson et al, 2007), species which are more difficult to measure and not routinely quantified. Measurements at a remote, clean site at Whiteface Mountain (upper New York State) showed only a slight diurnal variation with an average reactivity of 5.6 s −1 (Ren et al, 2006b) similar to that observed at another rural site at Rock Springs, Pennsylvania (Ren et al, 2005). Very recently, the first airborne measurements of OH reactivity were made (Mao et al, 2009).…”

Section: Introductionmentioning

confidence: 58%

A flow-tube based laser-induced fluorescence instrument to measure OH reactivity in the troposphere

et al. 2009

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Abstract.A field instrument utilising the artificial generation of OH radicals in a sliding injector flow-tube reactor with detection by laser-induced fluorescence spectroscopy has been developed to measure the rate of decay of OH by reaction with its atmospheric sinks. The OH reactivity instrument has been calibrated using known concentrations of CO, NO 2 and single hydrocarbons in a flow of zero air, and the impact of recycling of OH via the reaction HO 2 +NO→OH+NO 2 on the measured OH reactivity has been quantified. As well as a detailed description of the apparatus, the capabilities of the new instrument are illustrated using representative results from deployment in the semi-polluted marine boundary layer at the Weybourne Atmospheric Observatory, UK, and in a tropical rainforest at the Bukit Atur Global Atmospheric Watch station, Danum Valley, Borneo.

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“…Measurements of NO 3 have been overestimated by model calculations in several studies (Mihelcic et al, 1993;Sommariva et al, , 2007, with those of nighttime OH and HO 2 radicals typically underestimated, indicating poor understanding of nighttime tropospheric oxidation processes (Kanaya et al, 1999(Kanaya et al, , 2002(Kanaya et al, , 2007aEmmerson and Carslaw, 2009;Geyer et al, 2003;Faloona et al, 2001;Martinez et al, 2003;Ren et al, 2006). While a number of nighttime studies at ground level close to local sources of NO have observed a limited role of NO 3 in nighttime radical production owing to surface losses of NO 3 and the rapid reaction between NO 3 and NO (Salisbury et al, 2001;Fleming et al, 2006;Sommariva et al, 2007;Kanaya et al, 1999Kanaya et al, , 2002Kanaya et al, , 2007aEmmerson and Carslaw, 2009;Faloona et al, 2001;Martinez et al, 2003;Ren et al, 2003Ren et al, , 2005Ren et al, , 2006Volkamer et al, 2010), several studies of NO 3 and N 2 O 5 above ground level and in more remote regions have indicated a more significant role for NO 3 in nighttime radical production and tropospheric oxidation (Platt et al, 1980;Povey et al, 1998;South et al, 1998;Aliwell et al, 1998;Allan et al, 2002;Stutz et al, 2004;Brown et al, 2003Brown et al, , 2004Brown et al, , 2006Brown et al, , 2007Brown et al, , 2009...…”

Section: Introductionmentioning

confidence: 99%

Radical chemistry at night: comparisons between observed and modelled HOx, NO3 and N2O5 during the RONOCO project

et al. 2014

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Abstract. The RONOCO (ROle of Nighttime chemistry in controlling the Oxidising Capacity of the AtmOsphere) aircraft campaign during July 2010 and January 2011 made observations of OH, HO 2 , NO 3 , N 2 O 5 and a number of supporting measurements at night over the UK, and reflects the first simultaneous airborne measurements of these species. We compare the observed concentrations of these short-lived species with those calculated by a box model constrained by the concentrations of the longer lived species using a detailed chemical scheme. OH concentrations were below the limit of detection, consistent with model predictions. The model systematically underpredicts HO 2 by ∼ 200 % and overpredicts NO 3 and N 2 O 5 by around 80 and 50 %, respectively. Cycling between NO 3 and N 2 O 5 is fast and thus we define the NO 3x (NO 3x = NO 3 + N 2 O 5 ) family. Production of NO 3x is overwhelmingly dominated by the reaction of NO 2 with O 3 , whereas its loss is dominated by aerosol uptake of N 2 O 5 , with NO 3 + VOCs (volatile organic compounds) and NO 3 + RO 2 playing smaller roles. The production of HO x and RO x radicals is mainly due to the reaction of NO 3 with VOCs. The loss of these radicals occurs through a combination of HO 2 + RO 2 reactions, heterogeneous processes and production of HNO 3 from OH + NO 2 , with radical propagation primarily achieved through reactions of NO 3 with peroxy radicals. Thus NO 3 at night plays a similar role to both OH and NO during the day in that it both initiates RO x radical production and acts to propagate the tropospheric oxidation chain. Model sensitivity to the N 2 O 5 aerosol uptake coefficient (γ N 2 O 5 ) is discussed and we find that a value of γ N 2 O 5 = 0.05 improves model simulations for NO 3 and N 2 O 5 , but that these improvements are at the expense of model success for HO 2 . Improvements to model simulations for HO 2 , NO 3 and N 2 O 5 can be realised simultaneously on inclusion of additional unsaturated volatile organic compounds, however the nature of these compounds is extremely uncertain.

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Hydroxyl and Peroxy Radical Chemistry in a Rural Area of Central Pennsylvania: Observations and Model Comparisons

Cited by 68 publications

References 56 publications

Atmospheric oxidation in the Mexico City Metropolitan Area (MCMA) during April 2003

Atmospheric oxidation in the Mexico City Metropolitan Area (MCMA) during April 2003

A flow-tube based laser-induced fluorescence instrument to measure OH reactivity in the troposphere

Radical chemistry at night: comparisons between observed and modelled HO<sub>x</sub>, NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> during the RONOCO project

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Hydroxyl and Peroxy Radical Chemistry in a Rural Area of Central Pennsylvania: Observations and Model Comparisons

Cited by 68 publications

References 56 publications

Atmospheric oxidation in the Mexico City Metropolitan Area (MCMA) during April 2003

Atmospheric oxidation in the Mexico City Metropolitan Area (MCMA) during April 2003

A flow-tube based laser-induced fluorescence instrument to measure OH reactivity in the troposphere

Radical chemistry at night: comparisons between observed and modelled HO&lt;sub&gt;x&lt;/sub&gt;, NO&lt;sub&gt;3&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt; during the RONOCO project

Contact Info

Product

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Radical chemistry at night: comparisons between observed and modelled HO<sub>x</sub>, NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> during the RONOCO project