Photochemical Oxidant Processes in the Presence of Dust: An Evaluation of the Impact of Dust on Particulate Nitrate and Ozone Formation

To clarify the relationship between changes in photochemical oxidants’ (Ox) concentrations and their precursors in Kawasaki, a series of analyses were conducted using data on Ox, their precursors, nitrogen oxides (NOx) and volatile organic compounds (VOCs), and meteorology that had been monitored throughout the city of Kawasaki for 30 years from 1990 to 2019. The trend in air temperature was upward, wind speed was downward, and solar radiation was upward, indicating an increasing trend in meteorological factors in which Ox concentrations tend to be higher. Between 1990 and 2013, the annual average Ox increased throughout Kawasaki and remained flat after that. The three-year moving average of the daily peak increased until 2015, and after that, it exhibited a slight decline. The amount of generated Ox is another important indicator. To evaluate this, a new indicator, the daytime production of photochemical oxidant (DPOx), was proposed. DPOx is defined by daytime averaged Ox concentrations less the previous day’s nighttime averaged Ox concentrations. The trend in DPOx from April to October has been decreasing since around 2006, and it was found that this indicator reflects the impact of reducing emissions of NOx and VOCs in Kawasaki.

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Effect of isoprene emissions from major forests on ozone formation in the city of Shanghai, China

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-18527-2011 ◽

2011 ◽

Vol 11 (6) ◽

pp. 18527-18556 ◽

Cited By ~ 1

Author(s):

F. Geng ◽

X. Tie ◽

A. Guenther ◽

G. Li ◽

J. Cao ◽

...

Keyword(s):

Ozone Production ◽

Ozone Formation ◽

Emission Model ◽

Peroxy Radicals ◽

Forest Regions ◽

High Concentrations ◽

The Impact ◽

The City ◽

Continuous Oxidation ◽

Ho2 Radical

Abstract. Ambient surface level concentrations of isoprene (C5H8) were measured in the major forest regions located south of Shanghai, China. Because there is a large coverage of broad-leaved trees in this region, high concentrations of isoprene were measured, ranging from 1 to 6 ppbv. A regional dynamical/chemical model (WRF-Chem) is applied for studying the effect of such high concentrations of isoprene on the ozone production in the city of Shanghai. The evaluation of the model shows that the calculated isoprene concentrations agree with the measured concentrations when the measured isoprene concentrations are lower than 3 ppb, but underestimate the measurements when the measured values are higher than 3 ppb. Isoprene was underestimated only at sampling sites near large bamboo plantations, a high isoprene source, indicating the need to include geospatially resolved bamboo distributions in the biogenic emission model. The assessment of the impact of isoprene on ozone formation suggests that the concentrations of peroxy radicals (RO2) are significantly enhanced due to the oxidation of isoprene, with a maximum of 30 ppt. However, the enhancement of RO2 is confined to the forested regions. Because the concentrations of NOx were low in the forest regions, the ozone production due to the oxidation of isoprene (C5H8 + OH →→ RO2 + NO →→ O3) is low (less than 2–3 ppb/h). The calculation further suggests that the oxidation of isoprene leads to the enhancement of carbonyls (such as formaldehyde and acetaldehyde) in the regions downwind of the forests, due to continuous oxidation of isoprene in the forest air. As a result, the concentrations of HO2 radical are enhanced, resulting from the photo-disassociation of formaldehyde and acetaldehyde. Because the enhancement of HO2 radical occurs in regions downwind of the forests, the enhancement of ozone production (6–8 ppb/h) is higher than in the forest region, causing by higher anthropogenic emissions of NOx. This study suggests that the biogenic emissions in the major forests to the south of Shanghai have important impacts on the levels of ozone in the city, mainly due to the carbonyls produced by the continuous oxidation of isoprene in the forest air.

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Correction to Ozone Formation Induced by the Impact of Reactive Bromine and Iodine Species on Photochemistry in a Polluted Marine Environment

Environmental Science & Technology ◽

10.1021/acs.est.7b06319 ◽

2018 ◽

Vol 52 (3) ◽

pp. 1679-1679

Author(s):

M. Shechner ◽

E. Tas

Keyword(s):

Marine Environment ◽

Ozone Formation ◽

Iodine Species ◽

The Impact

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The stem-II regional scale acid deposition and photochemical oxidant model—IV. The impact of emission reductions on mesoscale acid deposition in the lower ohio river valley

Atmospheric Environment Part A General Topics ◽

10.1016/0960-1686(92)90244-f ◽

1992 ◽

Vol 26 (5) ◽

pp. 841-861 ◽

Cited By ~ 4

Author(s):

Rohit Mathur ◽

Rick D Saylor ◽

Leonard K Peters

Keyword(s):

Acid Deposition ◽

Regional Scale ◽

River Valley ◽

Ohio River ◽

Ohio River Valley ◽

Emission Reductions ◽

Photochemical Oxidant ◽

The Impact

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The impact of cloud chemistry on photochemical oxidant formation

Water Air & Soil Pollution ◽

10.1007/bf00282492 ◽

1985 ◽

Vol 24 (4) ◽

Cited By ~ 3

Author(s):

Christian Seigneur ◽

Pradeep Saxena

Keyword(s):

Cloud Chemistry ◽

Photochemical Oxidant ◽

The Impact

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The impact of biogenic VOC emissions on photochemical ozone formation during a high ozone pollution episode in the Iberian Peninsula in the 2003 summer season

Advances in Science and Research ◽

10.5194/asr-2-9-2008 ◽

2008 ◽

Vol 2 (1) ◽

pp. 9-15 ◽

Cited By ~ 4

Author(s):

N. Castell ◽

A. F. Stein ◽

R. Salvador ◽

E. Mantilla ◽

M. Millán

Keyword(s):

Organic Compound ◽

Iberian Peninsula ◽

Volatile Organic Compound ◽

Biogenic Emissions ◽

Ozone Formation ◽

Ozone Pollution ◽

Voc Emissions ◽

Volatile Organic ◽

Big Cities ◽

The Impact

Abstract. Throughout Europe the summer of 2003 was exceptionally warm, especially July and August. The European Environment Agency (EEA) reported several ozone episodes, mainly in the first half of August. These episodes were exceptionally long-lasting, spatially extensive, and associated to high temperatures. In this paper, the 10$ndash;15 August 2003 ozone pollution event has been analyzed using meteorological and regional air quality modelling. During this period the threshold values of the European Directive 2002/3/EC were exceeded in various areas of the Iberian Peninsula. The aim of this paper is to computationally understand and quantify the influence of biogenic volatile organic compound (BVOC) emissions in the formation of tropospheric ozone during this high ozone episode. Being able to differentiate how much ozone comes from biogenic emissions alone and how much comes from the interaction between anthropogenic and biogenic emissions would be helpful to develop a feasible and effective ozone control strategy. The impact on ozone formation was also studied in combination with various anthropogenic emission reduction strategies, i.e., when anthropogenic VOC emissions and/or NOx emissions are reduced. The results show a great dependency of the BVOC contribution to ozone formation on the antropoghenic reduction scenario. In rural areas, the impact due to a NOx and/or VOC reduction does not change the BVOC impact. Nevertheless, within big cities or industrial zones, a NOx reduction results in a decrease of the biogenic impact in ozone levels that can reach 85 μg/m3, whereas an Anthropogenic Volatile Organic Compound (AVOC) reduction results in a decrease of the BVOC contribution on ozone formation that varies from 0 to 30 μg/m3 with respect to the contribution at the same points in the 2003 base scenario. On the other hand, downwind of the big cities, a decrease in NOx produces a minor contribution of biogenic emissions and a decrease in AVOCs results in greater contributions of BVOCs to the formation of ozone.

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