Nitrogen dioxide measurement by cavity attenuated phase shift spectroscopy (CAPS) and implications in ozone production efficiency and nitrate formation in Beijing, China

Ge, Baozhu; Sun, Yele; Liu, Ying; Dong, Huabin; Ji, Dongsheng; Jiang, Qi; Li, Jie; Wang, Zifa

doi:10.1002/jgrd.50757

Cited by 45 publications

(33 citation statements)

References 63 publications

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“…For urban measurements, only the results from Mexico City in MCMA-03 were close to the Beijing results in the basic model run (Lei et al, 2008). For suburban measurements, the OPE in Heshan in 2014 was higher than in the other three campaigns, even including the results from the Shangdianzi station in the CAREBeijing-2008 campaign (Ge et al, 2013). While taking missing reactivity into consideration, the OPE results were even higher, indicating more ozone was produced by the reactions of the same quantity of NO x molecules.…”

Section: Implications For Ozone Production Efficiencymentioning

confidence: 54%

How the OH reactivity affects the ozone production efficiency: case studies in Beijing and Heshan, China

et al. 2017

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Abstract. Total OH reactivity measurements were conducted on the Peking University campus (Beijing) in August 2013 and in Heshan (Guangdong province) from October to November 2014. The daily median OH reactivity was 20 ± 11 s −1 in Beijing and 31 ± 20 s −1 in Heshan, respectively. The data in Beijing showed a distinct diurnal pattern with the maxima over 27 s −1 in the early morning and minima below 16 s −1 in the afternoon. The diurnal pattern in Heshan was not as evident as in Beijing. Missing reactivity, defined as the difference between measured and calculated OH reactivity, was observed at both sites, with 21 % missing reactivity in Beijing and 32 % missing reactivity in Heshan. Unmeasured primary species, such as branched alkenes, could contribute to missing reactivity in Beijing, especially during morning rush hours. An observation-based model with the RACM2 (Regional Atmospheric Chemical Mechanism version 2) was used to understand the daytime missing reactivity in Beijing by adding unmeasured oxygenated volatile organic compounds and simulated intermediates of the degradation from primary volatile organic compounds (VOCs). However, the model could not find a convincing explanation for the missing reactivity in Heshan, where the ambient air was found to be more aged, and the missing reactivity was presumably attributed to oxidized species, such as unmeasured aldehydes, acids and dicarbonyls. The ozone production efficiency was 21 % higher in Beijing and 30 % higher in Heshan when the model was constrained by the measured reactivity, compared to the calculations with measured and modeled species included, indicating the importance of quantifying the OH reactivity for better understanding ozone chemistry.

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Section: Implications For Ozone Production Efficiencymentioning

confidence: 54%

How the OH reactivity affects the ozone production efficiency: case studies in Beijing and Heshan, China

et al. 2017

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“…The instruments including a Cavity Attenuated Phase Shift Particulate Matter extinction monitor (CAPS-PM ext , Aerodyne Research Inc.) (Kebabian et al, 2007), a CAPS-NO 2 monitor (Kebabian et al, 2008;Ge et al, 2013), and a 7-wavelength Aethalometer 30 (model: AE33; Magee Scientific Corp.) (Drinovec et al, 2015) were equipped in the container for real-time measurements of light extinction coefficient (b ext , λ = 630 nm) of dry fine particles, gaseous NO 2 , and BC with a time resolution of 1 s, 1 s and Atmos. Chem.…”

Section: Experimental Methodsmentioning

confidence: 99%

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Wang¹,

Sun²,

Xu³

et al. 2017

Preprint

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Abstract. We conducted the first real-time continuous vertical measurements of particle extinction (b ext ), gaseous NO 2 , and black carbon (BC) from ground level to 260 m during two severe winter haze episodes at an urban site in Beijing, China. Our results illustrated four distinct types of vertical profiles: 1) uniform vertical distributions (37% of the time) with vertical differences less than 5%; 2) higher values at lower altitudes (29%); 3) higher values at higher altitudes (16%), and 4) 15 significant decreases at the heights of ~100 -150 m (14%). Further analysis demonstrated that vertical convection as indicated by mixing layer height, temperature inversion, and local emissions are three major factors affecting the changes in vertical profiles. Particularly, the formation of Type 4 was strongly associated with the stratified layer that was formed due to the interactions of different air masses and temperature inversions. Aerosol composition was substantially different below and above the transition heights with ~20 -30% higher contributions of local sources (e.g., biomass burning and cooking) at 20 lower altitudes. A more detailed evolution of vertical profiles and their relationship with the changes in source emissions, mixing layer height, and aerosol chemistry was illustrated by a case study. BC showed overall similar vertical profiles as those of b ext (R 2 = 0.92 and 0.69 in November and January, respectively). While NO 2 was correlated with b ext for most of the time, the vertical profiles of b ext /NO 2 varied differently for different profiles, indicating the impact of chemical transformation on vertical profiles. Our results also showed that more comprehensive vertical measurements (e.g., more 25 aerosol and gaseous species) at higher altitudes in the megacities are needed for a better understanding of the formation mechanisms and evolution of severe haze episodes in China.

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“…One should keep in mind that the pseudo-steady-state assumption requires precise NO 2 quantification, which may not be the case in our study as the Mo converter used for the NO 2 quantification could have interferences (Table 1). The overestimation due to thermal dissociations of reactive oxygenated nitrogen species has been reported to be 20 to 83 % (Ge et al, 2013;Steinbacher et al, 2007). In addition, Mannschreck et al (2004) presented the NO-NO 2 -ozone photostationary state analysis using a 4-year data set from a rural observational site in Hohenpeissenberg, Germany.…”

Section: Implications Of the Uncertainty In Ho X Estimations In Assesmentioning

confidence: 99%

Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

Kim

Lee³

et al. 2015

Atmos. Chem. Phys.

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Abstract. Rapid urbanization and economic development in East Asia in past decades has led to photochemical air pollution problems such as excess photochemical ozone and aerosol formation. Asian megacities such as Seoul, Tokyo, Shanghai, Guangzhou, and Beijing are surrounded by densely forested areas, and recent research has consistently demonstrated the importance of biogenic volatile organic compounds (VOCs) from vegetation in determining oxidation capacity in the suburban Asian megacity regions. Uncertainties in constraining tropospheric oxidation capacity, dominated by hydroxyl radical, undermine our ability to assess regional photochemical air pollution problems. We present an observational data set of CO, NO x , SO 2 , ozone, HONO, and VOCs (anthropogenic and biogenic) from Taehwa research forest (TRF) near the Seoul metropolitan area in early June 2012. The data show that TRF is influenced both by aged pollution and fresh biogenic volatile organic compound emissions. With the data set, we diagnose HO x (OH, HO 2 , and RO 2 ) distributions calculated using the University of Washington chemical box model (UWCM v2.1) with nearexplicit VOC oxidation mechanisms from MCM v3.2 (Master Chemical Mechanism). Uncertainty from unconstrained HONO sources and radical recycling processes highlighted in recent studies is examined using multiple model simulations with different model constraints. The results suggest that (1) different model simulation scenarios cause systematic differences in HO x distributions, especially OH levels (up to 2.5 times), and (2) radical destruction (HO 2 + HO 2 or HO 2 + RO 2 ) could be more efficient than radical recycling (RO 2 + NO), especially in the afternoon. Implications of the uncertainties in radical chemistry are discussed with respect to ozone-VOC-NO x sensitivity and VOC oxidation product formation rates. Overall, the NO x limited regime is assessed except for the morning hours (8 a.m. to 12 p.m. local standard time), but the degree of sensitivity can significantly vary depending on the model scenarios. The model results also suggest that RO 2 levels are positively correlated with oxygenated VOCs (OVOCs) production that is not routinely constrained by observations. These unconstrained OVOCs can cause higher-than-expected OH loss rates (missing OH reactivity) and secondary organic aerosol formation. The series of modeling experiments constrained by observations strongly urge observational constraint of the radical pool to enable precise understanding of regional photochemical pollution problems in the East Asian megacity region.

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Nitrogen dioxide measurement by cavity attenuated phase shift spectroscopy (CAPS) and implications in ozone production efficiency and nitrate formation in Beijing, China

Cited by 45 publications

References 63 publications

How the OH reactivity affects the ozone production efficiency: case studies in Beijing and Heshan, China

How the OH reactivity affects the ozone production efficiency: case studies in Beijing and Heshan, China

Vertically-resolved Characteristics of Air Pollution during Two Severe Winter Haze Episodes in Urban Beijing, China

Impact of isoprene and HONO chemistry on ozone and OVOC formation in a semirural South Korean forest

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