REGIONAL-SCALE MODELING OZONE AIR QUALITY OVER THE  CONTINENTAL SOUTH EAST ASIA

Long range transport of ozone and its precursors can significantly impact the air quality in downwind regions. The problem of regional transport of ozone has been studied for more than three decades in Europe and U.S but not yet in Southeast Asia. This study investigated the regional scale distribution of tropospheric ozone over the Continental South East Asia Region (CSEA) of Thailand, Burma, Cambodia, Lao and Vietnam. The Models-3 Community Multi-scale Air Quality (CMAQ modeling system, driven by the NCAR/Penn State Fifth-Generation Mesoscale Model (MM5), is used for the purpose. The model domain covers the longitude range from 91'E to 111°E and the latitude range from 5°N to 25°N. Two most recent ozone episodes of March 24-26, 2004 and January 2-4, 2005 were selected which represent the typical meteorological conditions for high ozone concentrations periods of a year. The episode analysis was made based on available data from 10 and 4 monitoring stations located in Bangkok of Thailand and Ho Chi Minh City (HCMC) of Vietnam, respectively. The episodes were characterized with hourly ozone levels above the National Ambient Air Quality Standards of Thailand and Vietnam of 100 ppb at a number of the monitoring stations. The maximum ground level concentrations of ozone for March 2004 and January 2005 episodes reached 173 ppb and 157 ppb, respectively, in the urban plume of the Bangkok Metropolitan Region (BMR). The simulations were performed with 0.5o 0.5° emission input data which was prepared from the regional anthropogenic emission inventory used in the Transport and Chemical Evolution over the Pacific (TRACE-P), and the biogenic emissions obtained from the Global Emissions Inventory Activity (GEIA). The simulated overall picture of ground level ozone concentrations over CSEA domain shows that the concentrations were high at the downwind areas at a considerable distance from large urban areas such as BMR and HCMC. During March 2004 episode the ozone plume moved northeastward following the Southwesterly monsoon and the maximum width of the modeled plume with the ozone above 100 ppb was about 70 km from BMR. For HCMC the ozone plume moved northward and the concentration in the city plume was lower with the width of isopleth of 50ppb of around 40 km. During the Jan 2005 episode the ozone plume moved southwestward following the Northeasterly monsoon and the width of the modeled plume with the ozone concentration above 100 ppb in BMR was 50 km while for HCMC the width of the 40ppb isopleth was about 30 km. The model performance was evaluated on the available observed hourly ozone concentrations. The model system was shown to be able to reproduce the peak ozone levels that occurred during the episodes at these two large urban areas, and capture the day by day variations during the selected episodes. The performance statistics MNBE, NGE, and UPA for the simulated ozone concentrations are within U.S. EPA guidance criteria and are comparable to those reported previous for other regional ozone simulations. It is shown that the MM5/CMAQ system is the suitable modeling tools for ozone prediction over the CSEA.

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Impact of external industrial sources on the regional and local air quality of Mexico Megacity

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-13-26579-2013 ◽

2013 ◽

Vol 13 (10) ◽

pp. 26579-26625

Author(s):

V. H. Almanza ◽

L. T. Molina ◽

G. Li ◽

J. Fast ◽

G. Sosa

Keyword(s):

Air Quality ◽

Regional Scale ◽

Ambient Air ◽

The State ◽

Combustion Model ◽

Potential Contribution ◽

Industrial Complex ◽

Ozone Levels ◽

Monitoring Stations

Abstract. The air quality of megacities can be influenced by external emissions sources on both global and regional scale, and at the same time their outflow emissions can exert an important impact to the surrounding environment. The present study evaluates an SO2 peak observed on 24 March 2006 at the suburban supersite T1 and ambient air quality monitoring stations located in the north region of the Mexico City Metropolitan Area (MCMA) during MILAGRO campaign. We found that this peak could be related to an important episodic emission event from Tizayuca region, northeast of the MCMA. Back trajectories analyses suggest that the emission event started in the early morning at 04:00 LST and lasted for about 9 h. The estimated emission rate is noticeably high, about 2 kg s−1. This finding suggests the possibility of "overlooked" emission sources in this region that could influence the air quality of the MCMA. This further motivated us to study the cement plants, including those in the State of Hidalgo and in the State of Mexico, and we found that they can contribute in the NE region of the basin (about 41.7%), at the suburban supersite T1 (41.23%) and at some monitoring stations their contribution can be even higher than from the Tula Industrial Complex. The contribution of Tula Industrial Complex to regional ozone levels is estimated. The model suggests low contribution to the MCMA (1 ppb to 4 ppb) and slightly higher at the suburban T1 (6 ppb) and rural T2 (5 ppb) supersites. However, the contribution could be as high as 10 ppb in the upper northwest region of the basin and in the southwest and south-southeast regions of State of Hidalgo. In addition, a first estimate of the potential contribution from flaring activities to regional ozone levels is presented. Emission rates are estimated with a CFD combustion model. Results suggest that up to 30% of the total regional ozone from TIC could be related to flaring activities. Finally, the influence in SO2 levels from technological changes in the existing refinery is briefly discussed. These changes are due to the upcoming construction of a new refinery in Tula. The combination of emission reductions in the power plant, the refinery and in local sources in the MCMA could result in higher reductions on the average SO2 concentration. Reductions in external sources tend to affect more the northern part of the basin (−16.35% to −45.58%), whilst reductions of urban sources in the megacity tend to diminish SO2 levels substantially in the central, southwest, and southeast regions (−30.71% to −49.75%).

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

Revista de Chimie ◽

10.37358/rc.17.4.5560 ◽

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.

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Regional Scale Impact of the COVID-19 Lockdown on Air Quality: Gaseous Pollutants in the Po Valley, Northern Italy

Atmosphere ◽

10.3390/atmos12020264 ◽

2021 ◽

Vol 12 (2) ◽

pp. 264 ◽

Cited By ~ 1

Author(s):

Giovanni Lonati ◽

Federico Riva

Keyword(s):

Air Quality ◽

Urban Areas ◽

Regional Scale ◽

High Volume ◽

Ambient Air ◽

Northern Italy ◽

Traffic Emissions ◽

Gaseous Pollutants ◽

Po Valley ◽

Concentration Levels

The impact of the reduced atmospheric emissions due to the COVID-19 lockdown on ambient air quality in the Po Valley of Northern Italy was assessed for gaseous pollutants (NO2, benzene, ammonia) based on data collected at the monitoring stations distributed all over the area. Concentration data for each month of the first semester of 2020 were compared with those of the previous six years, on monthly, daily, and hourly bases, so that pre, during, and post-lockdown conditions of air quality could be separately analyzed. The results show that, as in many other areas worldwide, the Po Valley experienced better air quality during 2020 spring months for NO2 and benzene. In agreement with the reductions of nitrogen oxides and benzene emissions from road traffic, estimated to be −35% compared to the regional average, the monthly mean concentration levels for 2020 showed reductions in the −40% to −35% range compared with the previous years, but with higher reductions, close to −50%, at high-volume-traffic sites in urban areas. Conversely, NH3 ambient concentration levels, almost entirely due the emissions of the agricultural sector, did not show any relevant change, even at high-volume-traffic sites in urban areas. These results point out the important role of traffic emissions in NO2 and benzene ambient levels in the Po Valley, and confirm that this region is a rather homogeneous air basin with urban area hot-spots, the contributions of which add up to a relatively high regional background concentration level. Additionally, the relatively slow response of the air quality levels to the sudden decrease of the emissions due to the lockdown shows that this region is characterized by a weak exchange of the air masses that favors both the build-up of atmospheric pollutants and the development of secondary formation processes. Thus, air quality control strategies should aim for structural interventions intended to reduce traffic emissions at the regional scale and not only in the largest urban areas.

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Contribution of Local and Transboundary Air Pollution to the Urban Air Quality of Fukuoka, Japan

Atmosphere ◽

10.3390/atmos12040431 ◽

2021 ◽

Vol 12 (4) ◽

pp. 431

Author(s):

Ayako Yoshino ◽

Akinori Takami ◽

Keiichiro Hara ◽

Chiharu Nishita-Hara ◽

Masahiko Hayashi ◽

...

Keyword(s):

Air Pollution ◽

Air Quality ◽

Urban Areas ◽

Air Pollutants ◽

Regional Scale ◽

Gaseous Species ◽

Transboundary Air Pollution ◽

Local Air Pollution ◽

The City

Transboundary air pollution (TAP) and local air pollution (LAP) influence the air quality of urban areas. Fukuoka, located on the west side of Japan and affected by TAP from the Asian continent, is a unique example for understanding the contribution of LAP and TAP. Gaseous species and particulate matter (PM) were measured for approximately three weeks in Fukuoka in the winter of 2018. We classified two distinctive periods, LAP and TAP, based on wind speed. The classification was supported by variations in the concentration of gaseous species and by backward trajectories. Most air pollutants, including NOx and PM, were high in the LAP period and low in the TAP period. However, ozone was the exception. Therefore, our findings suggest that reducing local emissions is necessary. Ozone was higher in the TAP period, and the variation in ozone concentration was relatively small, indicating that ozone was produced outside of the city and transported to Fukuoka. Thus, air pollutants must also be reduced at a regional scale, including in China.

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Temporal patterns and trends of surface ozone concentrations over Portugal

10.5194/egusphere-egu21-5119 ◽

2021 ◽

Author(s):

Carla Gama ◽

Alexandra Monteiro ◽

Myriam Lopes ◽

Ana Isabel Miranda

Keyword(s):

Air Quality ◽

Iberian Peninsula ◽

Human Health ◽

Temporal Variability ◽

Urban Areas ◽

Surface Ozone ◽

Quality Data ◽

Ozone Concentrations ◽

Long Term Study

Tropospheric ozone (O3) is a critical pollutant over the Mediterranean countries, including Portugal, due to systematic exceedances to the thresholds for the protection of human health. Due to the location of Portugal, on the Atlantic coast at the south-west point of Europe, the observed O3 concentrations are very much influenced not only by local and regional production but also by northern mid-latitudes background concentrations. Ozone trends in the Iberian Peninsula were previously analysed by Monteiro et al. (2012), based on 10-years of O3 observations. Nevertheless, only two of the eleven background monitoring stations analysed in that study are located in Portugal and these two stations are located in Porto and Lisbon urban areas. Although during pollution events O3 levels in urban areas may be high enough to affect human health, the highest concentrations are found in rural locations downwind from the urban and industrialized areas, rather than in cities. This happens because close to the sources (e.g., in urban areas) freshly emitted NO locally scavenges O3. A long-term study of the spatial and temporal variability and trends of the ozone concentrations over Portugal is missing, aiming to answer the following questions:-&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; What is the temporal variability of ozone concentrations?-&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; Which trends can we find in observations?-&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; How were the ozone spring maxima concentrations affected by the COVID-19 lockdown during spring 2020?In this presentation, these questions will be answered based on the statistical analysis of O3 concentrations recorded within the national air quality monitoring network between 2005 and 2020 (16 years). The variability of the surface ozone concentrations over Portugal, on the timescales from diurnal to annual, will be presented and discussed, taking into account the physical and chemical processes that control that variability. Using the TheilSen function from the OpenAir package for R (Carslaw and Ropkins 2012), which quantifies monotonic trends and calculates the associated p-value through bootstrap simulations, O3 concentration long-term trends will be estimated for the different regions and environments (e.g., rural, urban).&#160; Moreover, taking advantage of the unique situation provided by the COVID-19 lockdown during spring 2020, when the government imposed mandatory confinement and citizens movement restriction, leading to a reduction in traffic-related atmospheric emissions, the role of these emissions on ozone levels during the spring period will be studied and presented.&#160;Carslaw and Ropkins, 2012. Openair&#8212;an R package for air quality data analysis. Environ. Model. Softw. 27-28,52-61. https://doi.org/10.1016/j.envsoft.2011.09.008Monteiro et al., 2012. Trends in ozone concentrations in the Iberian Peninsula by quantile regression and clustering. Atmos. Environ. 56, 184-193. https://doi.org/10.1016/j.atmosenv.2012.03.069

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The impacts of precursor reduction and meteorology on ground-level ozone in the Greater Toronto Area

Atmospheric Chemistry and Physics ◽

10.5194/acp-14-8197-2014 ◽

2014 ◽

Vol 14 (15) ◽

pp. 8197-8207 ◽

Cited By ~ 21

Author(s):

S. C. Pugliese ◽

J. G. Murphy ◽

J. A. Geddes ◽

J. M. Wang

Keyword(s):

Health Hazard ◽

Ground Level ◽

Ozone Production ◽

Ground Level Ozone ◽

Ozone Concentrations ◽

Greater Toronto Area ◽

High Solar Radiation ◽

Linear Effects ◽

Human Health Hazard ◽

Ozone Levels

Abstract. Tropospheric ozone (O3) is a major component of photochemical smog and is a known human health hazard, as well as a damaging factor for vegetation. Its precursor compounds, nitrogen oxides (NOx) and volatile organic compounds (VOCs), have a variety of anthropogenic and biogenic sources and exhibit non-linear effects on ozone production. As an update to previous studies on ground-level ozone in the Greater Toronto Area (GTA), we present an analysis of NO2, VOC and O3 data from federal and provincial governmental monitoring sites in the GTA from 2000 to 2012. We show that, over the study period, summertime 24 h VOC reactivity and NO2 midday (11:00–15:00) concentrations at all sites decreased significantly; since 2000, all sites experienced a decrease in NO2 of 28–62% and in measured VOC reactivity of at least 53–71%. Comparing 2002–2003 to 2011–2012, the summed reactivity of OH towards NO2 and a suite of measured VOCs decreased from 8.6 to 4.6 s−1. Ratios of reactive VOC pairs indicate that the effective OH concentration experienced by primary pollutants in the GTA has increased significantly over the study period. Despite the continuous decrease in precursor levels, ozone concentrations are not following the same pattern at all stations; it was found that the Canada-wide Standard for ozone continues to be exceeded at all monitoring stations. Additionally, while the years 2008–2011 had consistently lower ozone levels than previous years, 2012 experienced one of the highest recorded summertime ozone concentrations and a large number of smog episodes. We demonstrate that these high ozone observations in 2012 may be a result of the number of days with high solar radiation, the number of stagnant periods and the transport of high ozone levels from upwind regions.

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Air Quality Modeling in Dense Urban Areas at Ground Level—CFD, OSM or Gauss?

10.1007/978-3-662-63760-9_37 ◽

2021 ◽

pp. 265-270

Author(s):

Marie Haeger-Eugensson ◽

Christine Achberger ◽

Helen Nygren ◽

Erik Bäck ◽

Anna Bjurbäck ◽

...

Keyword(s):

Air Quality ◽

Urban Areas ◽

Ground Level ◽

Air Quality Modeling ◽

Quality Modeling

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Explicit Modeling of Meteorological Explanatory Variables in Short-Term Forecasting of Maximum Ozone Concentrations via a Multiple Regression Time Series Framework

Atmosphere ◽

10.3390/atmos11121304 ◽

2020 ◽

Vol 11 (12) ◽

pp. 1304

Author(s):

Sigfrido Iglesias-Gonzalez ◽

Maria E. Huertas-Bolanos ◽

Ivan Y. Hernandez-Paniagua ◽

Alberto Mendoza

Keyword(s):

Time Series ◽

Air Quality ◽

Multiple Regression ◽

Urban Areas ◽

Moving Average ◽

Time Series Forecasting ◽

Air Pollutant ◽

Short Term ◽

Ozone Level ◽

Ozone Concentrations

Statistical time series forecasting is a useful tool for predicting air pollutant concentrations in urban areas, especially in emerging economies, where the capacity to implement comprehensive air quality models is limited. In this study, a general multiple regression with seasonal autoregressive moving average errors model was estimated and implemented to forecast maximum ozone concentrations with a short time resolution: overnight, morning, afternoon and evening. In contrast to a number of short-term air quality time series forecasting applications, the model was designed to explicitly include the effects of meteorological variables on the ozone level as exogenous variables. As the application location, the model was constructed with data from five monitoring stations in the Monterrey Metropolitan Area of Mexico. The results show that, together with structural stochastic components, meteorological parameters have a significant contribution for obtaining reliable forecasts. The resulting model is an interpretable, useful and easily implementable model for forecasting ozone maxima. Moreover, it proved to be consistent with the general dynamics of ozone formation and provides a suitable platform for forecasting, showing similar or better performance compared to models in other existing studies.

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Source Contributions to Ozone Formation in the New South Wales Greater Metropolitan Region, Australia

Atmosphere ◽

10.3390/atmos9110443 ◽

2018 ◽

Vol 9 (11) ◽

pp. 443 ◽

Cited By ~ 7

Author(s):

Hiep Nguyen Duc ◽

Lisa Chang ◽

Toan Trieu ◽

David Salter ◽

Yvonne Scorgie

Keyword(s):

Air Quality ◽

New South ◽

New South Wales ◽

Metropolitan Region ◽

North West ◽

Ozone Concentrations ◽

South Wales ◽

Source Contributions ◽

Ozone Levels ◽

Different Parts

Ozone and fine particles (PM2.5) are the two main air pollutants of concern in the New South Wales Greater Metropolitan Region (NSW GMR) due to their contribution to poor air quality days in the region. This paper focuses on source contributions to ambient ozone concentrations for different parts of the NSW GMR, based on source emissions across the greater Sydney region. The observation-based Integrated Empirical Rate model (IER) was applied to delineate the different regions within the GMR based on the photochemical smog profile of each region. Ozone source contribution was then modelled using the CCAM-CTM (Cubic Conformal Atmospheric model-Chemical Transport model) modelling system and the latest air emission inventory for the greater Sydney region. Source contributions to ozone varied between regions, and also varied depending on the air quality metric applied (e.g., average or maximum ozone). Biogenic volatile organic compound (VOC) emissions were found to contribute significantly to median and maximum ozone concentration in North West Sydney during summer. After commercial and domestic sources, power generation was found to be the next largest anthropogenic source of maximum ozone concentrations in North West Sydney. However, in South West Sydney, beside commercial and domestic sources, on-road vehicles were predicted to be the most significant contributor to maximum ozone levels, followed by biogenic sources and power stations. The results provide information that policy makers can use to devise various options to control ozone levels in different parts of the NSW Greater Metropolitan Region.

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A Machine Learning Approach to Predict Air Quality in California

Complexity ◽

10.1155/2020/8049504 ◽

2020 ◽

Vol 2020 ◽

pp. 1-23 ◽

Cited By ~ 2

Author(s):

Mauro Castelli ◽

Fabiana Martins Clemente ◽

Aleš Popovič ◽

Sara Silva ◽

Leonardo Vanneschi

Keyword(s):

Machine Learning ◽

Air Quality ◽

Environmental Protection Agency ◽

Urban Areas ◽

Principal Component ◽

Ground Level ◽

Support Vector ◽

Validation Data ◽

Pollutant Concentrations ◽

Rbf Kernel

Predicting air quality is a complex task due to the dynamic nature, volatility, and high variability in time and space of pollutants and particulates. At the same time, being able to model, predict, and monitor air quality is becoming more and more relevant, especially in urban areas, due to the observed critical impact of air pollution on citizens’ health and the environment. In this paper, we employ a popular machine learning method, support vector regression (SVR), to forecast pollutant and particulate levels and to predict the air quality index (AQI). Among the various tested alternatives, radial basis function (RBF) was the type of kernel that allowed SVR to obtain the most accurate predictions. Using the whole set of available variables revealed a more successful strategy than selecting features using principal component analysis. The presented results demonstrate that SVR with RBF kernel allows us to accurately predict hourly pollutant concentrations, like carbon monoxide, sulfur dioxide, nitrogen dioxide, ground-level ozone, and particulate matter 2.5, as well as the hourly AQI for the state of California. Classification into six AQI categories defined by the US Environmental Protection Agency was performed with an accuracy of 94.1% on unseen validation data.

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