Observations of atmospheric oxidation and ozone production in South Korea

Abstract. Atmospheric oxidation capacity is the core of converting fresh-emitted substances to secondary pollutants. In this study, we present the in-situ measurements at four Chinese megacities (Beijing, Shanghai, Guangzhou, and Chongqing) in China during photochemical polluted seasons. The atmospheric oxidation capacity is evaluated using an observational-based model with the input of radical chemistry precursor measurements. The radical budget analysis illustrates the importance of HONO and HCHO photolysis, which contribute nearly half of the total radical primary sources. The radical propagation is efficient due to abundant of NO in the urban environments. Hence, the production rate of secondary pollutants, i.e. ozone and fine particle precursors (H2SO4, HNO3, and ELVOCs) is fast resulting in secondary air pollution. The ozone budget demonstrates that strong ozone production occurs in the urban area which results in fast ozone concentration increase locally and further transported to downwind areas. On the other hand, the O3-NOx-VOC sensitivity tests show that ozone production is VOC-limited, among which alkenes and aromatics should be first mitigated for ozone pollution control in the presented four megacities. However, NOx emission control will lead to more server ozone pollution due to the drawback-effect of NOx reduction. For fine particle pollution, the role of HNO3−NO3− partitioning system is investigated with a thermal dynamic model (ISORROPIA2) due to the importance of particulate nitrate during photochemical polluted seasons. The strong nitrate acid production converts efficiently to nitrate particles due to high RH and ammonium-rich conditions during photochemical polluted seasons. This study highlights the efficient radical chemistry maintains the atmospheric oxidation capacity in Chinese megacities, which results in secondary pollutions characterized by ozone and fine particles.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-6-2753-2006 ◽

2006 ◽

Vol 6 (9) ◽

pp. 2753-2765 ◽

Cited By ~ 169

Author(s):

T. R. Shirley ◽

W. H. Brune ◽

X. Ren ◽

J. Mao ◽

R. Lesher ◽

...

Keyword(s):

Steady State ◽

Developing Country ◽

Mexico City ◽

Metropolitan Area ◽

Urban Studies ◽

Ozone Production ◽

Atmospheric Oxidation ◽

European Cities

Abstract. The Mexico City Metropolitan Area (MCMA) study in April 2003 had measurements of many atmospheric constituents, including OH and HO2. 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 (~7×106 cm−3), comparable to amounts observed in U.S. cities, but HO2 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 HO2 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 HO2/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 HO2/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 HO2 reached 50 ppb h−1, a much higher rate than observed in U.S. cities.

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Automated sequence analysis of atmospheric oxidation pathways: SEQUENCE version 1.0

Geoscientific Model Development ◽

10.5194/gmd-2-145-2009 ◽

2009 ◽

Vol 2 (2) ◽

pp. 145-152

Author(s):

T. M. Butler

Keyword(s):

Sequence Analysis ◽

Sequential Analysis ◽

Chemical Species ◽

Ozone Production ◽

Atmospheric Oxidation ◽

Product Yields ◽

Intermediate Products ◽

Photochemical Model ◽

Detailed Picture

Abstract. An algorithm for the sequential analysis of the atmospheric oxidation of chemical species using output from a photochemical model is presented. Starting at a "root species", the algorithm traverses all possible reaction sequences which consume this species, and lead, via intermediate products, to final products. The algorithm keeps track of the effects of all of these reactions on their respective reactants and products. Upon completion, the algorithm has built a detailed picture of the effects of the oxidation of the root species on its chemical surroundings. The output of the algorithm can be used to determine product yields, radical recycling fractions, and ozone production potentials of arbitrary chemical species.

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The Controlling Factors of Photochemical Ozone Production in Seoul, South Korea

Aerosol and Air Quality Research ◽

10.4209/aaqr.2017.11.0452 ◽

2018 ◽

Vol 18 (9) ◽

pp. 2253-2261 ◽

Cited By ~ 6

Author(s):

Saewung Kim ◽

Daun Jeong ◽

Dianne Sanchez ◽

Mark Wang ◽

Roger Seco ◽

...

Keyword(s):

South Korea ◽

Controlling Factors ◽

Ozone Production ◽

Photochemical Ozone

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Atmospheric oxidation chemistry and ozone production: Results from SHARP 2009 in Houston, Texas

Journal of Geophysical Research Atmospheres ◽

10.1002/jgrd.50342 ◽

2013 ◽

Vol 118 (11) ◽

pp. 5770-5780 ◽

Cited By ~ 44

Author(s):

Xinrong Ren ◽

Diana van Duin ◽

Maria Cazorla ◽

Shuang Chen ◽

Jingqiu Mao ◽

...

Keyword(s):

Ozone Production ◽

Atmospheric Oxidation ◽

Oxidation Chemistry

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Daytime atmospheric oxidation capacity in four Chinese megacities during the photochemically polluted season: a case study based on box model simulation

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-3493-2019 ◽

2019 ◽

Vol 19 (6) ◽

pp. 3493-3513 ◽

Cited By ~ 28

Author(s):

Zhaofeng Tan ◽

Keding Lu ◽

Meiqing Jiang ◽

Rong Su ◽

Hongli Wang ◽

...

Keyword(s):

Urban Areas ◽

Fine Particle ◽

Fine Particles ◽

Model Simulation ◽

Ozone Production ◽

Atmospheric Oxidation ◽

Ozone Pollution ◽

Oxidation Capacity ◽

Radical Chemistry ◽

Budget Analysis

Abstract. Atmospheric oxidation capacity is the basis for converting freshly emitted substances into secondary products and is dominated by reactions involving hydroxyl radicals (OH) during daytime. In this study, we present in situ measurements of ROx radical (hydroxy OH, hydroperoxy HO2, and organic peroxy RO2) precursors and products; the measurements are carried out in four Chinese megacities (Beijing, Shanghai, Guangzhou, and Chongqing) during photochemically polluted seasons. The atmospheric oxidation capacity is evaluated using an observation-based model and radical chemistry precursor measurements as input. The radical budget analysis illustrates the importance of HONO and HCHO photolysis, which account for ∼50 % of the total primary radical sources. The radical propagation is efficient due to abundant NO in urban environments. Hence, the production rate of secondary pollutants, that is, ozone (and fine-particle precursors (H2SO4, HNO3, and extremely low volatility organic compounds, ELVOCs) is rapid, resulting in secondary air pollution. The ozone budget demonstrates its high production in urban areas; also, its rapid transport to downwind areas results in rapid increase in local ozone concentrations. The O3–NOx–VOC (volatile organic compound) sensitivity tests show that ozone production is VOC-limited and that alkenes and aromatics should be mitigated first for ozone pollution control in the four studied megacities. In contrast, NOx emission control (that is, a decrease in NOx) leads to more severe ozone pollution. With respect to fine-particle pollution, the role of the HNO3–NO3 partitioning system is investigated using a thermal dynamic model (ISORROPIA 2). Under high relative humidity (RH) and ammonia-rich conditions, nitric acid converts into nitrates. This study highlights the efficient radical chemistry that maintains the atmospheric oxidation capacity in Chinese megacities and results in secondary pollution characterized by ozone and fine particles.

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Atmospheric Oxidation Mechanism of Isoprene

Environmental Chemistry ◽

10.1071/en04045 ◽

2004 ◽

Vol 1 (3) ◽

pp. 140 ◽

Cited By ~ 105

Author(s):

Jiwen Fan ◽

Renyi Zhang

Keyword(s):

Atmospheric Aerosols ◽

Oxidation Mechanism ◽

Box Model ◽

Ozone Production ◽

Atmospheric Oxidation ◽

Theoretical Studies ◽

Model Intercomparison ◽

Isoprene Oxidation ◽

Oxidation Mechanisms ◽

Recent Laboratory

Environmental Context. Many plant species biosynthesize and emit the volatile hydrocarbon isoprene. Once in the atmosphere, isoprene is susceptible to a range of reactions involving potentially hundred of products and intermediate compounds. The products of these reactions in turn may pose a risk to human and plant health and impact the climate through the generation of acids, ozone, and atmospheric aerosols. Abstract. The atmospheric oxidation mechanism of isoprene initiated by OH, O3, NO3, and Cl, which incorporates the most recent laboratory and theoretical studies, is described. A box model intercomparison between the new mechanism and previous available isoprene oxidation mechanisms has been performed. Ozone and OH concentrations are compared with predictions by the previous mechanisms in high and low NOx scenarios. The O3 and OH sensitivities to the chlorine−isoprene reactions have also been investigated by comparing the box model results with and without the chlorine−isoprene reactions, showing that the ozone production rate and OH concentrations are slightly impacted. The new mechanism facilitates more accurate modelling of isoprene photochemistry in the atmosphere.

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

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-5-6041-2005 ◽

2005 ◽

Vol 5 (4) ◽

pp. 6041-6076 ◽

Cited By ~ 2

Author(s):

T. R. Shirley ◽

W. H. Brune ◽

X. Ren ◽

J. Mao ◽

R. Lesher ◽

...

Keyword(s):

Production Rate ◽

Mexico City ◽

Metropolitan Area ◽

Urban Studies ◽

Ozone Production ◽

Atmospheric Oxidation ◽

European Cities ◽

Early Afternoon ◽

Modeling Uncertainties ◽

Us Cities

Abstract. The Mexico City Metropolitan Area (MCMA) study in April 2003 had measurements of most atmospheric constituents including OH and HO2. It provided a unique opportunity to examine atmospheric oxidation in a megacity that has more pollution than typical US and European cities. OH typically reached 0.35 pptv (~7×106 cm−3), comparable to amounts observed in US cities, but HO2 reached 40 pptv in the early afternoon, more than observed in most US cities. A steady-state photochemical model simulated the measured OH and HO2 for day and night to within combined measurement and modeling uncertainties for 2/3 of the results. For OH, measured = 0.65 (modeled) + 0.026 pptv, with R2=0.80. For HO2, observed = 0.70 (modeled) + 3.4 pptv, with R2=0.64. Measurements tended to be higher during night and rush hour; the model was higher by ~30% during midday. With a large median measured OH reactivity of more than 120 s−1 during morning rush hour, median ozone production from observed HO2 reached 50 ppb hr−1; RO2 was calculated to have a similar ozone production rate. For both the HO2/OH ratio and the ozone production, the measured values have the essentially same dependence on NO as the modeled values. This similarity is unlike other urban studies in which the NO-dependence of the measured HO2/OH ratio was much less than the modeled ratio and the ozone production rate that was calculated from measured HO2 unexpectedly appeared to increase as a function of NO with no obvious peak.

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Atmospheric oxidation in the presence of clouds during the Deep Convective Clouds and Chemistry (DC3) study

Atmospheric Chemistry and Physics ◽

10.5194/acp-18-14493-2018 ◽

2018 ◽

Vol 18 (19) ◽

pp. 14493-14510 ◽

Cited By ~ 3

Author(s):

William H. Brune ◽

Xinrong Ren ◽

Li Zhang ◽

Jingqiu Mao ◽

David O. Miller ◽

...

Keyword(s):

Chemical Species ◽

Mesoscale Convective System ◽

Chemical Mechanism ◽

Ozone Production ◽

Atmospheric Oxidation ◽

Convective System ◽

Heterogeneous Chemistry ◽

Convective Clouds ◽

Deep Convective Clouds ◽

Oxidation Chemistry

Abstract. Deep convective clouds are critically important to the distribution of atmospheric constituents throughout the troposphere but are difficult environments to study. The Deep Convective Clouds and Chemistry (DC3) study in 2012 provided the environment, platforms, and instrumentation to test oxidation chemistry around deep convective clouds and their impacts downwind. Measurements on the NASA DC-8 aircraft included those of the radicals hydroxyl (OH) and hydroperoxyl (HO2), OH reactivity, and more than 100 other chemical species and atmospheric properties. OH, HO2, and OH reactivity were compared to photochemical models, some with and some without simplified heterogeneous chemistry, to test the understanding of atmospheric oxidation as encoded in the model. In general, the agreement between the observed and modeled OH, HO2, and OH reactivity was within the combined uncertainties for the model without heterogeneous chemistry and the model including heterogeneous chemistry with small OH and HO2 uptake consistent with laboratory studies. This agreement is generally independent of the altitude, ozone photolysis rate, nitric oxide and ozone abundances, modeled OH reactivity, and aerosol and ice surface area. For a sunrise to midday flight downwind of a nighttime mesoscale convective system, the observed ozone increase is consistent with the calculated ozone production rate. Even with some observed-to-modeled discrepancies, these results provide evidence that a current measurement-constrained photochemical model can simulate observed atmospheric oxidation processes to within combined uncertainties, even around convective clouds. For this DC3 study, reduction in the combined uncertainties would be needed to confidently unmask errors or omissions in the model chemical mechanism.

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Atmospheric Oxidation in the Presence of Clouds during the Deep Convective Clouds and Chemistry (DC3) Study

10.5194/acp-2018-120 ◽

2018 ◽

Author(s):

William H. Brune ◽

Xinrong Ren ◽

Li Zhang ◽

Jinqiu Mao ◽

David O. Miller ◽

...

Keyword(s):

Chemical Species ◽

Mesoscale Convective System ◽

Ozone Production ◽

Atmospheric Oxidation ◽

Convective System ◽

Heterogeneous Chemistry ◽

Convective Clouds ◽

Deep Convective Clouds ◽

Oxidation Chemistry ◽

Photochemical Models

Abstract. Deep convective clouds are critically important to the distribution of atmospheric constituents throughout the troposphere but are difficult environments to study. The Deep Convective Clouds and Chemistry (DC3) study provided the environment, platforms, and instrumentation to test oxidation chemistry around deep convective clouds and their impacts downwind. Measurements on the NASA DC-8 aircraft included those of hydroxyl (OH), hydroperoxyl (HO2), OH reactivity, and more than 100 other chemical species and atmospheric properties. OH, HO2, and OH reactivity were compared to photochemical models, some with and some without simplified heterogeneous chemistry, to test the understanding of atmospheric oxidation as encoded in the model. In general, the agreement between the observed and modeled OH, HO2, and OH reactivity were all well within the combined uncertainties for both the model without heterogeneous chemistry and the model that includes heterogeneous chemistry with small OH and HO2 uptake consistent with laboratory studies. This agreement is generally independent of the altitude, ozone photolysis rate, nitric oxide and ozone abundances, modeled OH reactivity, and aerosol and ice surface area. For a sunrise to midday flight downwind of a nighttime mesoscale convective system, the observed ozone increase is consistent with the calculated ozone production rate. Even with some observed-to-modeled discrepancies, these results provide evidence that current photochemical models, properly constrained with measurements, can generally simulate observed atmospheric oxidation processes even around clouds.

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