scholarly journals Meandering Dispersion Model Applied to Air Pollution

10.5772/16892 ◽  
2011 ◽  
Author(s):  
Gervasio A. ◽  
Andrea U. ◽  
Virnei S. ◽  
Debora R.
Keyword(s):  
Air Pollution ◽  
Dispersion Model

scholarly journals Development of a Line Source Dispersion Model for Gaseous Pollutants by Incorporating Wind Shear near the Ground under Stable Atmospheric Conditions

2020 ◽  
Vol 4 (1) ◽  
pp. 17
Author(s):  
Saisantosh Vamshi Harsha Madiraju ◽  
Ashok Kumar
Keyword(s):  
Air Pollution ◽  
Urban Areas ◽  
Wind Shear ◽  
Dispersion Model ◽  
Near Field ◽  
Ground Level ◽  
Gaseous Pollutants ◽  
Air Pollution Control ◽  
Mobile Sources ◽  
Input Variables

Transportation sources are a major contributor to air pollution in urban areas. The role of air quality modeling is vital in the formulation of air pollution control and management strategies. Many models have appeared in the literature to estimate near-field ground level concentrations from mobile sources moving on a highway. However, current models do not account explicitly for the effect of wind shear (magnitude) near the ground while computing the ground level concentrations near highways from mobile sources. This study presents an analytical model based on the solution of the convective-diffusion equation by incorporating the wind shear near the ground for gaseous pollutants. The model input includes emission rate, wind speed, wind direction, turbulence, and terrain features. The dispersion coefficients are based on the near field parameterization. The sensitivity of the model to compute ground level concentrations for different inputs is presented for three different downwind distances. In general, the model shows Type III sensitivity (i.e., the errors in the input will show a corresponding change in the computed ground level concentrations) for most of the input variables. However, the model equations should be re-examined for three input variables (wind velocity at the reference height and two variables related to the vertical spread of the plume) to make sure that that the model is valid for computing ground level concentrations.

scholarly journals Early Pregnancy Exposure to Ambient Air Pollution among Late-Onset Preeclamptic Cases Is Associated with Placental DNA Hypomethylation of Specific Genes and Slower Placental Maturation

Toxics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 338
Author(s):  
Karin Engström ◽  
Yumjirmaa Mandakh ◽  
Lana Garmire ◽  
Zahra Masoumi ◽  
Christina Isaxon ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Air Pollution ◽  
Early Pregnancy ◽  
Late Onset ◽  
Dispersion Model ◽  
Ambient Air ◽  
Ambient Air Pollution ◽  
Dna Hypomethylation ◽  
Increased Risk

Exposure to ambient air pollution during pregnancy has been associated with an increased risk of preeclampsia (PE). Some suggested mechanisms behind this association are changes in placental DNA methylation and gene expression. The objective of this study was to identify how early pregnancy exposure to ambient nitrogen oxides (NOx) among PE cases and normotensive controls influence DNA methylation (EPIC array) and gene expression (RNA-seq). The study included placentas from 111 women (29 PE cases/82 controls) in Scania, Sweden. First-trimester NOx exposure was assessed at the participants’ residence using a dispersion model and categorized via median split into high or low NOx. Placental gestational epigenetic age was derived from the DNA methylation data. We identified six differentially methylated positions (DMPs, q < 0.05) comparing controls with low NOx vs. cases with high NOx and 14 DMPs comparing cases and controls with high NOx. Placentas with female fetuses showed more DMPs (N = 309) than male-derived placentas (N = 1). Placentas from PE cases with high NOx demonstrated gestational age deceleration compared to controls with low NOx (p = 0.034). No differentially expressed genes (DEGs, q < 0.05) were found. In conclusion, early pregnancy exposure to NOx affected placental DNA methylation in PE, resulting in placental immaturity and showing sexual dimorphism.

scholarly journals Arctic smoke – record high air pollution levels in the European Arctic due to agricultural fires in Eastern Europe

2006 ◽  
Vol 6 (5) ◽  
pp. 9655-9722 ◽  
Author(s):  
A. Stohl ◽  
T. Berg ◽  
J. F. Burkhart ◽  
A. M. Fjæraa ◽  
C. Forster ◽  
...  
Keyword(s):  
Air Pollution ◽  
Eastern Europe ◽  
Dispersion Model ◽  
Spatial Scales ◽  
Agricultural Waste ◽  
Particle Dispersion ◽  
The Arctic ◽  
Aerosol Size Distribution ◽  
Radiative Processes ◽  
European Arctic

Abstract. In spring 2006, the European Arctic was abnormally warm, setting new historical temperature records. During this warm period, smoke from agricultural fires in Eastern Europe intruded into the European Arctic and caused the most severe air pollution episodes ever recorded there. This paper confirms that biomass burning (BB) was indeed the source of the observed air pollution, studies the transport of the smoke into the Arctic, and presents an overview of the observations taken during the episode. Fire detections from the MODIS instruments aboard the Aqua and Terra satellites were used to estimate the BB emissions. The FLEXPART particle dispersion model was used to show that the smoke was transported to Spitsbergen and Iceland, which was confirmed by MODIS retrievals of the aerosol optical depth (AOD) and AIRS retrievals of carbon monoxide (CO) total columns. Concentrations of halocarbons, carbon dioxide and CO, as well as levoglucosan and potassium, measured at Zeppelin mountain near Ny Ålesund, were used to further corroborate the BB source of the smoke at Spitsbergen. The ozone (O3) and CO concentrations were the highest ever observed at the Zeppelin station, and gaseous elemental mercury was also enhanced. A new O3 record was also set at a station on Iceland. The smoke was strongly absorbing – black carbon concentrations were the highest ever recorded at Zeppelin –, and strongly perturbed the radiation transmission in the atmosphere: aerosol optical depths were the highest ever measured at Ny Ålesund. We furthermore discuss the aerosol chemical composition, obtained from filter samples, as well as the aerosol size distribution during the smoke event. Photographs show that the snow at a glacier on Spitsbergen became discolored during the episode and, thus, the snow albedo was reduced. Samples of this polluted snow contained strongly enhanced levels of potassium, sulphate, nitrate and ammonium ions, thus relating the discoloration to the deposition of the smoke aerosols. This paper shows that, to date, BB has been underestimated as a source of aerosol and air pollution for the Arctic, relative to emissions from fossil fuel combustion. Given its significant impact on air quality over large spatial scales and on radiative processes, the practice of agricultural waste burning should be banned in the future.

scholarly journals 2110 Prenatal near roadway air pollution exposure and early neurodevelopment in young Mexican-American children: Findings from the CHAMACOS prospective birth cohort study

2018 ◽  
Vol 2 (S1) ◽  
pp. 86-86
Author(s):  
William H. Coe ◽  
Jason Feinberg ◽  
Robert Grunier ◽  
Brenda Eskenazi ◽  
Heather Volk
Keyword(s):  
Air Pollution ◽  
Birth Cohort ◽  
Motor Development ◽  
Mexican American ◽  
Dispersion Model ◽  
Birth Cohort Study ◽  
Linear Regression Models ◽  
Scale Scores ◽  
American Children ◽  
Prospective Birth Cohort

OBJECTIVES/SPECIFIC AIMS: Previous studies suggest that prenatal exposure to environmental pollutants can have an adverse effect on brain development. We examine the association between prenatal near roadway air pollution (NRAP) exposure and early neurodevelopment. METHODS/STUDY POPULATION: The Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) Study is a prospective birth cohort that began in 1999 with 605 mother-child pairs of primarily Mexican-American descent. Maternal residence during pregnancy was geocoded using ArcGIS and prenatal NRAP exposure was assigned using the CALINE4 line source dispersion model. We used composite Bayley Scale scores for cognitive and motor development, and created separate linear regression models at 6, 12, and 24 months of age. RESULTS/ANTICIPATED RESULTS: After adjusting for relevant maternal and child characteristics, preliminary estimates suggest that prenatal NRAP exposure is associated with a nonsignificant increase in Bayley Scale scores at 6 and 24 months (cognitive: β=0.13, p-value=0.20 and motor: β=0.08, p-value=0.58 at 6 months; cognitive: β=0.16, p-value=0.42 and motor: β=0.20, p-value=0.25 at 24 months) and a nonsignificant decrease at 12 months (cognitive: β=−0.07, p-value=0.64 and motor: β=−0.12, p-value=0.56). DISCUSSION/SIGNIFICANCE OF IMPACT: Our preliminary findings do not suggest that prenatal NRAP exposure is associated with early cognitive development. Additional exploration of co-exposures known to effect neurodevelopment should be examined in this rural population.

A numerical air pollution dispersion model for central Stockholm

1974 ◽  
Vol 8 (2) ◽  
pp. 131-148 ◽  
Author(s):  
Björn Bringfelt ◽  
Thomas Hjorth ◽  
Sture Ring
Keyword(s):  
Air Pollution ◽  
Dispersion Model ◽  
Pollution Dispersion ◽  
Air Pollution Dispersion

scholarly journals Aircraft measurements over Europe of an air pollution plume from Southeast Asia – aerosol and chemical characterization

2007 ◽  
Vol 7 (3) ◽  
pp. 913-937 ◽  
Author(s):  
A. Stohl ◽  
C. Forster ◽  
H. Huntrieser ◽  
H. Mannstein ◽  
W. W. McMillan ◽  
...  
Keyword(s):  
Air Pollution ◽  
Southeast Asia ◽  
Dispersion Model ◽  
Chemical Characterization ◽  
Anthropogenic Pollution ◽  
Zonal Flow ◽  
Particle Dispersion ◽  
Upper Troposphere ◽  
Nucleation Mode ◽  
Average Maximum

Abstract. An air pollution plume from Southern and Eastern Asia, including regions in India and China, was predicted by the FLEXPART particle dispersion model to arrive in the upper troposphere over Europe on 24–25 March 2006. According to the model, the plume was exported from Southeast Asia six days earlier, transported into the upper troposphere by a warm conveyor belt, and travelled to Europe in a fast zonal flow. This is confirmed by the retrievals of carbon monoxide (CO) from AIRS satellite measurements, which are in excellent agreement with the model results over the entire transport history. The research aircraft DLR Falcon was sent into this plume west of Spain on 24 March and over Southern Europe on 25 March. On both days, the pollution plume was found close to the predicted locations and, thus, the measurements taken allowed the first detailed characterization of the aerosol content and chemical composition of an anthropogenic pollution plume after a nearly hemispheric transport event. The mixing ratios of CO, reactive nitrogen (NOy) and ozone (O3) measured in the Asian plume were all clearly elevated over a background that was itself likely elevated by Asian emissions: CO by 17–34 ppbv on average (maximum 60 ppbv) and O3 by 2–9 ppbv (maximum 22 ppbv). Positive correlations existed between these species, and a ΔO3/ΔCO slope of 0.25 shows that ozone was formed in this plume, albeit with moderate efficiency. Nucleation mode and Aitken particles were suppressed in the Asian plume, whereas accumulation mode aerosols were strongly elevated and correlated with CO. The suppression of the nucleation mode was likely due to the large pre-existing aerosol surface of the transported larger particles. Super-micron particles, likely desert dust, were found in part of the Asian pollution plume and also in surrounding cleaner air. The aerosol light absorption coefficient was enhanced in the plume (average values for individual plume encounters 0.25–0.70 Mm−1), as was the fraction of non-volatile Aitken particles. This indicates that black carbon (BC) was an important aerosol component. During the flight on 25 March, which took place on the rear of a trough located over Europe, a mixture of Asian pollution and stratospheric air was found. Asian pollution was mixing into the lower stratosphere, and stratospheric air was mixing into the pollution plume in the troposphere. Turbulence was encountered by the aircraft in the mixing regions, where the thermal stability was low and Richardson numbers were below 0.2. The result of the mixing can clearly be seen in the trace gas data, which are following mixing lines in correlation plots. This mixing with stratospheric air is likely very typical of Asian air pollution, which is often lifted to the upper troposphere and, thus, transported in the vicinity of stratospheric air.

National Trace-Element Air Pollution Monitoring Survey Using Epiphytic Lichens

1991 ◽  
Vol 23 (2) ◽  
pp. 139-165 ◽  
Author(s):  
J. E. Sloof ◽  
H. Th. Wolterbeek
Keyword(s):  
Air Pollution ◽  
Trace Element ◽  
Dispersion Model ◽  
Pollution Monitoring ◽  
Deciduous Tree ◽  
Data Sets ◽  
Air Pollution Monitoring ◽  
Geographical Concentration ◽  
National Monitoring ◽  
Concentration Patterns

AbstractTwo national monitoring surveys were carried out within 5 years, using Parmelia sulcata as a biomonitor of trace-element air pollution. The method of sampling was standardized. The lichen samples were analysed by neutron activation analysis. Local variations in element concentrations in lichens from various deciduous tree species from several sampling sites were established. The geographical concentration patterns obtained from the lichen data sets agreed with the element concentration gradients obtained from one dispersion model and measured data of atmospheric concentrations and deposition. Comparison of the two lichen data sets showed the relationship of the geographical concentration patterns with time. Combination of the available data gave insight into the possibility of localization of pollution sources.

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