Unveiling the dipole synergic effect of biogenic and anthropogenic emissions on ozone concentrations

2021 ◽  
pp. 151722
Author(s):  
Yang Gao ◽  
Feifan Yan ◽  
Mingchen Ma ◽  
Aijun Ding ◽  
Hong Liao ◽  
...  
Keyword(s):  
Anthropogenic Emissions ◽  
Synergic Effect ◽  
Ozone Concentrations

scholarly journals Regional-scale transport of air pollutants: impacts of Southern California emissions on Phoenix ground-level ozone concentrations

2015 ◽  
Vol 15 (16) ◽  
pp. 9345-9360 ◽  
Author(s):  
J. Li ◽  
M. Georgescu ◽  
P. Hyde ◽  
A. Mahalov ◽  
M. Moustaoui
Keyword(s):  
Metropolitan Area ◽  
Southern California ◽  
Regional Scale ◽  
Ground Level ◽  
Transport Processes ◽  
Anthropogenic Emissions ◽  
Ground Level Ozone ◽  
Ozone Concentrations ◽  
Phoenix Metropolitan Area ◽  
The Phoenix

Abstract. In this study, WRF-Chem is utilized at high resolution (1.333 km grid spacing for the innermost domain) to investigate impacts of southern California anthropogenic emissions (SoCal) on Phoenix ground-level ozone concentrations ([O3]) for a pair of recent exceedance episodes. First, WRF-Chem control simulations, based on the US Environmental Protection Agency (EPA) 2005 National Emissions Inventories (NEI05), are conducted to evaluate model performance. Compared with surface observations of hourly ozone, CO, NOX, and wind fields, the control simulations reproduce observed variability well. Simulated [O3] are comparable with the previous studies in this region. Next, the relative contribution of SoCal and Arizona local anthropogenic emissions (AZ) to ozone exceedances within the Phoenix metropolitan area is investigated via a trio of sensitivity simulations: (1) SoCal emissions are excluded, with all other emissions as in Control; (2) AZ emissions are excluded with all other emissions as in Control; and (3) SoCal and AZ emissions are excluded (i.e., all anthropogenic emissions are eliminated) to account only for Biogenic emissions and lateral boundary inflow (BILB). Based on the USEPA NEI05, results for the selected events indicate the impacts of AZ emissions are dominant on daily maximum 8 h average (DMA8) [O3] in Phoenix. SoCal contributions to DMA8 [O3] for the Phoenix metropolitan area range from a few ppbv to over 30 ppbv (10–30 % relative to Control experiments). [O3] from SoCal and AZ emissions exhibit the expected diurnal characteristics that are determined by physical and photochemical processes, while BILB contributions to DMA8 [O3] in Phoenix also play a key role. Finally, ozone transport processes and pathways within the lower troposphere are investigated. During daytime, pollutants (mainly ozone) near the Southern California coasts are pumped into the planetary boundary-layer over the Southern California desert through the mountain chimney and pass channel effects, aiding eastward transport along the desert air basins in southern California and finally, northeastward along the lower Gila River basin in Arizona, thereby affecting Phoenix air quality during subsequent days. This study indicates that local emission controls in Phoenix need to be augmented with regional emission reductions to attain the federal ozone standard, especially if a more stringent standard is adopted in the future.

scholarly journals Regional-scale transport of air pollutants: impacts of southern California emissions on Phoenix ground-level ozone concentrations

2015 ◽  
Vol 15 (6) ◽  
pp. 8361-8401
Author(s):  
J. Li ◽  
M. Georgescu ◽  
P. Hyde ◽  
A. Mahalov ◽  
M. Moustaoui
Keyword(s):  
Metropolitan Area ◽  
Southern California ◽  
Regional Scale ◽  
Ground Level ◽  
Transport Processes ◽  
Anthropogenic Emissions ◽  
Ground Level Ozone ◽  
Ozone Concentrations ◽  
Phoenix Metropolitan Area ◽  
The Phoenix

Abstract. In this study, WRF-Chem is utilized at high-resolution (1.333 km grid spacing for the innermost domain) to investigate impacts of southern California anthropogenic emissions (SoCal) on Phoenix ground-level ozone concentrations ([O3]) for a pair of recent exceedance episodes. First, WRF-Chem Control simulations are conducted to evaluate model performance. Compared with surface observations of hourly ozone, CO, NOx, and wind fields, the Control simulations reproduce observed variability well. Simulated [O3] are within acceptance ranges recommended by the Environmental Protection Agency (EPA) that characterize skillful experiments. Next, the relative contribution of SoCal and Arizona local anthropogenic emissions (AZ) to ozone exceedance within the Phoenix metropolitan area is investigated via a trio of sensitivity simulations: (1) SoCal emissions are excluded, with all other emissions as in Control; (2) AZ emissions are excluded with all other emissions as in Control; and (3) SoCal and AZ emissions are excluded (i.e., all anthropogenic emissions are eliminated) to account only for biogenic emissions [BEO]. Results for the selected events indicate the impacts of AZ emissions are dominant on daily maximum 8 h average (DMA8) [O3] in Phoenix. SoCal contributions to DMA8 [O3] for the Phoenix metropolitan area range from a few ppbv to over 30 ppbv (10–30% relative to Control experiments). [O3] from SoCal and AZ emissions exhibit the expected diurnal characteristics that are determined by physical and photochemical processes, while BEO contributions to DMA8 [O3] in Phoenix also play a key role. Finally, ozone transport processes and pathways within the lower troposphere are investigated. During daytime, pollutants (mainly ozone) near the southern California coasts are pumped into the planetary boundary-layer over the southern California desert through the mountain chimney and pass channel effects, aiding eastward transport along the desert air basins in southern California and finally, northeastward along the Gila River basin in Arizona, thereby affecting Phoenix air quality during subsequent days. This study indicates that local emission controls in Phoenix need to be augmented with regional emission reductions to attain the federal ozone standard, especially if a more stringent standard is adopted in future years.

scholarly journals Analysis of European ozone trends in the period 1995–2014

2017 ◽  
Author(s):  
Yingying Yan ◽  
Andrea Pozzer ◽  
Narendra Ojha ◽  
Jintai Lin ◽  
Jos Lelieveld
Keyword(s):  
Statistical Analysis ◽  
Temporal Variability ◽  
Climate Model ◽  
Surface Ozone ◽  
Anthropogenic Emissions ◽  
Annual Variations ◽  
Ozone Concentrations ◽  
Background Ozone ◽  
Ozone Trends ◽  
Ozone Levels

Abstract. Surface-based measurements from the EMEP network are used to estimate the changes in surface ozone levels during the 1995–2014 period over Europe. It is shown that a significantly decreasing trend in the 95th percentile ozone concentrations has occurred, especially during noontime (0.9 µg/m3/y), while the 5th percentile ozone concentrations continued to increase with a trend of 0.3 µg/m3/y during the study period. With the help of numerical simulations performed with the global chemistry-climate model EMAC, the importance of anthropogenic emissions changes in determining these changes are investigated. The EMAC model is found to successfully capture the observed temporal variability in mean ozone concentrations, as well as the contrast in the trends of 95th and 5th percentile ozone over Europe. Sensitivity simulations and statistical analysis show that a decrease in European anthropogenic emissions had contrasting effects on surface ozone trends between the 95th and 5th percentile levels, and that background ozone levels have been influenced by hemispheric transport, while climate variability generally regulated the inter-annual variations of surface ozone in Europe.

scholarly journals Analysis of European ozone trends in the period 1995–2014

2018 ◽  
Vol 18 (8) ◽  
pp. 5589-5605 ◽  
Author(s):  
Yingying Yan ◽  
Andrea Pozzer ◽  
Narendra Ojha ◽  
Jintai Lin ◽  
Jos Lelieveld
Keyword(s):  
Temporal Variability ◽  
Climate Model ◽  
Surface Ozone ◽  
Anthropogenic Emissions ◽  
Annual Variations ◽  
Ozone Concentrations ◽  
Background Ozone ◽  
Ozone Trends ◽  
Annual Means ◽  
Ozone Levels

Abstract. Surface-based measurements from the EMEP and Airbase networks are used to estimate the changes in surface ozone levels during the 1995–2014 period over Europe. We find significant ozone enhancements (0.20–0.59 µg m−3 yr−1 for the annual means; P-value  <  0.01 according to an F-test) over the European suburban and urban stations during 1995–2012 based on the Airbase sites. For European background ozone observed at EMEP sites, it is shown that a significantly decreasing trend in the 95th percentile ozone concentrations has occurred, especially at noon (0.9 µg m−3 yr−1; P-value  <  0.01), while the 5th percentile ozone concentrations continued to increase with a trend of 0.3 µg m−3 yr−1 (P-value  <  0.01) during the study period. With the help of numerical simulations performed with the global chemistry-climate model EMAC, the importance of anthropogenic emissions changes in determining these changes over background sites are investigated. The EMAC model is found to successfully capture the observed temporal variability in mean ozone concentrations, as well as the contrast in the trends of 95th and 5th percentile ozone over Europe. Sensitivity simulations and statistical analysis show that a decrease in European anthropogenic emissions had contrasting effects on surface ozone trends between the 95th and 5th percentile levels and that background ozone levels have been influenced by hemispheric transport, while climate variability generally regulated the inter-annual variations of surface ozone in Europe.

scholarly journals Contributions of foreign, domestic and natural emissions to US ozone estimated using the path-integral method in CAMx nested within GEOS-Chem

2017 ◽  
Author(s):  
Alan M. Dunker ◽  
Bonyoung Koo ◽  
Greg Yarwood
Keyword(s):  
Path Integral ◽  
Integral Method ◽  
Anthropogenic Sources ◽  
Anthropogenic Emissions ◽  
Base Case ◽  
Relative Importance ◽  
Natural Background ◽  
Air Quality Model ◽  
Ozone Concentrations ◽  
Path Integral Method

Abstract. The Goddard Earth Observing System global chemical transport (GEOS-Chem) model was used at 2° × 2.5° resolution to simulate ozone formation for a base case representing year 2010 and a natural background case without worldwide anthropogenic emissions. These simulations provided boundary concentrations for base and natural background simulations with the Comprehensive Air Quality Model with Extensions (CAMx) on a North American domain at 12 km × 12 km resolution over March–September 2010. The predicted maximum daily average 8-hour (MDA8) background ozone for the US is largest in the mountainous areas of Colorado, New Mexico, Arizona, and California. The background MDA8 ozone in some of these locations exceeds 60 ppb, when averaged over the 10 days with the largest base-case ozone. The ozone difference between the base and background cases represents the increment to ozone from all anthropogenic sources. Using the Path-Integral Method, the anthropogenic ozone increment was allocated to US anthropogenic emissions, Canadian/Mexican anthropogenic emissions, and the anthropogenic components of the lateral and top boundary concentrations (BCs). For the larger MDA8 ozone concentrations in the base case, the relative importance of the sources is generally US emissions > anthropogenic lateral BCs > Canadian/Mexican emissions &amp;gg; anthropogenic top BCs. The contributions of the lateral BCs are largest for the higher elevation US sites in the Intermountain West and sites closest to the boundaries. If the focus instead is on the larger ozone concentrations in the background case, the contribution from US emissions is reduced leading to a reduction in the anthropogenic ozone increment. The contribution of the Canadian/Mexican emissions remains about the same, and the contribution from the lateral BCs increases at lower elevation urban sites. The net effect is that the relative importance of the anthropogenic lateral BCs is significantly increased for the days with the largest background concentrations. In addition to the source apportionment, we also used surface and ozonesonde measurements to evaluate GEOS-Chem and CAMx performance.

Crosstalk between Sonic hedgehog and CRH pathways leading to a synergic effect on ACTH secretion

2004 ◽  
Vol 112 (S 1) ◽  
Author(s):  
G Vila ◽  
M Theodoropoulou ◽  
M Papazoglou ◽  
J Stalla ◽  
U Renner ◽  
...  
Keyword(s):  
Sonic Hedgehog ◽  
Synergic Effect ◽  
Acth Secretion

Considerations on Ambient Levels of Ozone Concentrations and Relationship with NOx in an Urban Environment

2017 ◽  
Vol 68 (4) ◽  
pp. 824-829
Author(s):  
Cornel Ianache ◽  
Laurentiu Predescu ◽  
Mirela Predescu ◽  
Dumitru Dumitru
Keyword(s):  
Nitrogen Oxides ◽  
Urban Areas ◽  
Road Traffic ◽  
Temporal Distribution ◽  
Ground Level ◽  
Distinct Pattern ◽  
Weekend Effect ◽  
Monitoring Site ◽  
Ground Level Ozone ◽  
Ozone Concentrations

The serious air pollution problem has determined public concerns, worldwide. One of the main challenges for countries all over the world is caused by the elevated levels of ground-level ozone (O3) concentrations and its anthropogenic precursors. Ploiesti city, as one of the major urban area of Romania, is facing the same situation. This research aims to investigate spatial and temporal distribution characteristics of O3 in relationship with nitrogen oxides (NOx) using statistical analysis methods. Hourly O3 and NOx measurements were collected during 2014 year in Ploiesti. The results obtained showed that the ozone spatial distribution was non-normal for each month in 2014. The diurnal cycle of ground-level ozone concentrations showed a mid-day peak, while NOx diurnal variations presented 2 daily peaks, one in the morning (7:00 a.m.) and one in the afternoon (between 5:00 and 7:00 p.m.). In addition, it was observed a distinct pattern of weekly variations for O3 and NOx. Like in many other urban areas, the results indicated the presence of the �ozone weekend effect� in Ploiesti during the 2014 year, ozone concentrations being slightly higher on weekends compared to weekdays. For the same monitoring site, the nitrogen oxides were less prevalent on Saturdays and Sundays, probably due to reducing of road traffic and other pollution-generating activities on weekends than during the week.

Extraction of hafnium(IV) with organophosphorus reagents from solutions of mineral acids mixtures

1979 ◽  
Vol 44 (12) ◽  
pp. 3656-3664
Author(s):  
Oldřich Navrátil ◽  
Jiří Smola ◽  
Rostislav Kolouch
Keyword(s):  
Ionic Strength ◽  
Aqueous Phase ◽  
Organic Phase ◽  
Perchloric Acid ◽  
Synergic Effect ◽  
Salting Out ◽  
Initial Concentration ◽  
Mixed Complexes ◽  
Synergic Extraction ◽  
Mineral Acids

Extraction of hafnium(IV) was studied from solutions of mixtures of perchloric and nitric acids and of perchloric and hydrochloric acids for constant ionic strength, I = 2, 4, 6, or 8, and for cHf 4 . 10-4 mol l-1. The organic phase was constituted by solutions of some acidic or neutral organophosphorus reagents or of 2-thenoyltrifluoroacetone, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone, or N-benzoyl-N-phenylhydroxylamine in benzene, chloroform, or n-octane. A pronounced synergic extraction of hafnium proceeds only on applying organophosphorus reagents from an aqueous phase whose acidity is not lower than 3M-(HClO4 + HNO3) or 5M-(HClO4 + HCl). The synergic effect was not affected markedly by a variation of the initial concentration of hafnium in the range 1 . 10-8 -4 .10-4 mol l-1, it lowered with increasing initial concentration of the organophosphorus reagent and decreasing concentration of the H+ ions. It is suggested that the hafnium passes into the organic phase in the form of mixed complexes, the salting-out effect of perchloric acid playing an appreciable part.

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