In this paper, a case study of applying the CALPUFF modeling for regional haze analysis is conducted for an industrial source with potential impact on a nearby Class I area. Results for a base case are discussed and influences of several variables on modeling results are evaluated.
O presente trabalho tem por objetivo utilizar o Método dos Mínimos Quadrados (MMQ) para analisar através do coeficiente de determinação (R2), qual modelo que melhor se ajusta ao comportamento do conjunto de dados da concentração de HCFC-142b em partes por trilhão entre os anos de 1992 a 2018. Ademais, pretende-se fazer estimativas de concentrações futuras entre 5 e 10 períodos em cada um dos modelos de ajuste.
Examination of Total Precipitable Water using MODIS measurements and Comparis...inventionjournals
In this research, precipitable water vapor, as the most effective character in the production of biomass is estimated using remote sensing techniques. Total Precipitable Water (TPW) was estimated using measurements in the Near Infrared bands of the MODIS. To examine the level of confidence in TPW deriving, a simultaneous in situ measurement by Radiosonde and ground-based Global Positioning System (GPS) was carried out. The TPW as results in Radiosonde and GPS was accomplished using the relevant physical equations and base on wet delay troposphere, respectively. Results showed a high correlation among the values of TPW derived from MODIS banding ratio, Radiosonde and GPS data at the Mehrabad station. Also, Using the ratio of the apparent reflectance in the water vapor absorption band to reflectance in non-absorbing band, the atmospheric water vapor transparency was mapped, that the maps showed a high correlation between apparent reflectance and TPW MODIS as their statistical results showed an inverse negative relationship(R²= -0.97).
O presente trabalho tem por objetivo utilizar o Método dos Mínimos Quadrados (MMQ) para analisar através do coeficiente de determinação (R2), qual modelo que melhor se ajusta ao comportamento do conjunto de dados da concentração de HCFC-142b em partes por trilhão entre os anos de 1992 a 2018. Ademais, pretende-se fazer estimativas de concentrações futuras entre 5 e 10 períodos em cada um dos modelos de ajuste.
Examination of Total Precipitable Water using MODIS measurements and Comparis...inventionjournals
In this research, precipitable water vapor, as the most effective character in the production of biomass is estimated using remote sensing techniques. Total Precipitable Water (TPW) was estimated using measurements in the Near Infrared bands of the MODIS. To examine the level of confidence in TPW deriving, a simultaneous in situ measurement by Radiosonde and ground-based Global Positioning System (GPS) was carried out. The TPW as results in Radiosonde and GPS was accomplished using the relevant physical equations and base on wet delay troposphere, respectively. Results showed a high correlation among the values of TPW derived from MODIS banding ratio, Radiosonde and GPS data at the Mehrabad station. Also, Using the ratio of the apparent reflectance in the water vapor absorption band to reflectance in non-absorbing band, the atmospheric water vapor transparency was mapped, that the maps showed a high correlation between apparent reflectance and TPW MODIS as their statistical results showed an inverse negative relationship(R²= -0.97).
First results from_the_hubble_opal_program_jupiter_in_2015Sérgio Sacani
Os cientistas usando o Telescópio Espacial Hubble da NASA/ESA produziram novos mapas de Júpiter, que mostram as contínuas mudanças que ocorrem com a famosa Grande Mancha Vermelha. As imagens também revelam uma rara estrutura em forma de onda na atmosfera do planeta que não tinha sido vista por décadas. A nova imagem é a primeira de uma série de retratos anuais dos planetas externos do Sistema Solar, que nos darão um novo olhar desses mundos remotos, e ajudarão os cientistas a estudarem como eles mudam com o passar do tempo.
Nessa nova imagem de Júpiter, uma grande quantidade de feições foi capturada incluindo ventos, nuvens e tempestades. Os cientistas por trás dessas novas imagens, as obtiveram usando a Wide Field Camera 3 do Hubble, num período de observação de mais de 10 horas e produziram assim dois mapas completos do planeta, a partir das suas observações. Esses mapas fizeram com que fosse possível determinar a velocidade dos ventos em Júpiter, com a finalidade de identificar diferentes fenômenos na sua atmosfera além de traquear as suas feições mais famosas.
As novas imagens confirmam que a grande tempestade que tem existido na superfície de nuvens de Júpiter por no mínimo 300 anos, continua a encolher, mas mesmo que desapareça, ela irá morrer lutando. A tempestade, conhecida como Grande Mancha Vermelha, é vista aqui fazendo seus movimentos em espiral no centro da imagem do planeta. Ela tem diminuído de tamanho de maneira muito rápida de ano em ano. Mas agora, a taxa de encolhimento parece ter reduzido novamente, mesmo apesar da mancha ser cerca de 240 quilômetros menor do que era em 2014.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Infrared Spectroscopy and its potential for estimation of soil propertiesExternalEvents
The second lab managers’ meeting of the South-East Asia Laboratory NETwork (SEALNET) took place on 19 - 23 November 2018 in ICAR-IISS (Indian Institute of Soil Science), Bhopal, India.
Dr. K M Hati, Principal Scientist, ICAR-IISS, Bhopal, India (1st Day)
Generating and Using Meteorological Data in AERMOD BREEZE Software
AERMOD, the preferred model of the U.S. EPA for near-field air dispersion modeling, requires the use of two meteorological files: the surface (.SFC) and profile (.PFL) files.
Using Visibility Analyses As An Alternative Approach To Regulate Air Quality BREEZE Software
This paper will examine the U.S. experience in modeling visibility impairment and to shed some light on the potential application of similar concepts in other countries.
First results from_the_hubble_opal_program_jupiter_in_2015Sérgio Sacani
Os cientistas usando o Telescópio Espacial Hubble da NASA/ESA produziram novos mapas de Júpiter, que mostram as contínuas mudanças que ocorrem com a famosa Grande Mancha Vermelha. As imagens também revelam uma rara estrutura em forma de onda na atmosfera do planeta que não tinha sido vista por décadas. A nova imagem é a primeira de uma série de retratos anuais dos planetas externos do Sistema Solar, que nos darão um novo olhar desses mundos remotos, e ajudarão os cientistas a estudarem como eles mudam com o passar do tempo.
Nessa nova imagem de Júpiter, uma grande quantidade de feições foi capturada incluindo ventos, nuvens e tempestades. Os cientistas por trás dessas novas imagens, as obtiveram usando a Wide Field Camera 3 do Hubble, num período de observação de mais de 10 horas e produziram assim dois mapas completos do planeta, a partir das suas observações. Esses mapas fizeram com que fosse possível determinar a velocidade dos ventos em Júpiter, com a finalidade de identificar diferentes fenômenos na sua atmosfera além de traquear as suas feições mais famosas.
As novas imagens confirmam que a grande tempestade que tem existido na superfície de nuvens de Júpiter por no mínimo 300 anos, continua a encolher, mas mesmo que desapareça, ela irá morrer lutando. A tempestade, conhecida como Grande Mancha Vermelha, é vista aqui fazendo seus movimentos em espiral no centro da imagem do planeta. Ela tem diminuído de tamanho de maneira muito rápida de ano em ano. Mas agora, a taxa de encolhimento parece ter reduzido novamente, mesmo apesar da mancha ser cerca de 240 quilômetros menor do que era em 2014.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Infrared Spectroscopy and its potential for estimation of soil propertiesExternalEvents
The second lab managers’ meeting of the South-East Asia Laboratory NETwork (SEALNET) took place on 19 - 23 November 2018 in ICAR-IISS (Indian Institute of Soil Science), Bhopal, India.
Dr. K M Hati, Principal Scientist, ICAR-IISS, Bhopal, India (1st Day)
Generating and Using Meteorological Data in AERMOD BREEZE Software
AERMOD, the preferred model of the U.S. EPA for near-field air dispersion modeling, requires the use of two meteorological files: the surface (.SFC) and profile (.PFL) files.
Using Visibility Analyses As An Alternative Approach To Regulate Air Quality BREEZE Software
This paper will examine the U.S. experience in modeling visibility impairment and to shed some light on the potential application of similar concepts in other countries.
Retrieval & monitoring of atmospheric green house gases (gh gs) through remot...debasishagri
Climate change is one of the most important global environmental challenges of this century. Green House Gases (GHGs) are the main culprit for this problem. Though much of research has already been done about the distribution and sources (and sinks) of GHGs , still much more uncertainties are present. Currently, there are only a few satellite instruments in orbit which are able to measure atmospheric GHGs. The High Resolution Infrared Radiation Sounder (HIRS), the Atmospheric InfraRed Sounder (AIRS), and the Infrared Atmospheric Sounding Interferometer (IASI) perform measurements in the thermal infrared (TIR) spectral region. But these are having low sensitivity to lower troposphere. In contrast to this, the sensitivity of instruments measuring reflected solar radiation in the near-infrared (NIR)/shortwave infrared (SWIR) spectral region is much more constant (with height) and shows maximum values near the surface. At present, SCIAMACHY aboard ENVISAT launched in 2002 and TANSO (Thermal And Near infrared Sensor for carbon Observation) aboard GOSAT (Greenhouse gases Observing SATellite) launched in 2009 are the only orbiting instruments measuring in NIR region. Among all the algorithms the WFM-DOAS algorithm (Weighting Function Modified Differential Optical Absorption Spectroscopy) developed at the University of Bremen for the retrieval of trace gases from SCIAMACHY (Buchwitz et al.2005) is mostly used. This is based on the principle of differential detection of radiance in gaseous absorption channels with respect to neighboring atmospheric transparent spectral channels (not influenced by gas) to detect the conc. of desired gas. But scattering at aerosol and/or cloud particles remains a major source of uncertainty for SCIAMACHY XCO2 retrievals(Houweling 2005, Schneising 2008).Of late with the use of new merged fit window approach scientists have come up with less than 0.5 ppm error in the estimation of CO2 in the presence of thin cirrus cloud(Reuter, Buchwitz et. al. 2010). Schneising et. al.,2007,retrieved d three year’s column-averaged CO2 dry air mole fraction from the SCIAMACHY instrument using the retrieval algorithm WFM-DOAS version 1.0, with precision of about 2 ppm. In India a study was undertaken to compare the atmospheric methane concentration pattern from SCIAMACHY with the vegetation dynamics from SPOT, showed fairly good correlation of methane emission with the rice cultivation(Goroshi et. al.).
Sensitivity of AERMOD in Modeling Fugitive Dust Emission Sources BREEZE Software
"This paper explores common presumptions about fugitive source modeling techniques by examining the sensitivity of predicted PM ambient concentrations to the choice of model
(AERMOD versus ISCST3), changes in source representation (volume versus area source), and variations in chosen source dimensions. "
Simulation of Height of Stack Pile using SCREEN3 module for Particulate Matte...IJERA Editor
This study is regarding the air pollution in selected areas near to port (beside stack yards of port) interested in particulate matter pollution. In this study, the amount of air pollution due to particulates is analyzed. The amount of air pollution is estimated using SCREEN 3 Methodology. In this study, SCREEN 3 methodology is a predefined software tool which can be used to estimate particulate matter pollution levels at different source release heights, terrain heights and at particular receptor height. The results obtained are reported and finally concluded that to avoid the pollution in the selected area, it is better to construct a periphery along the sides of stack yard (source of pollution).
Introduction
The transport sectors, including land transport, shipping and
aviation, are major sources of atmospheric pollution (e.g.,
Righi et al., 2013). The emissions from transport are growing
more rapidly than those from the other anthropogenic activities.
According to the ATTICA assessment (Uherek et al.,
2010; Eyring et al., 2010), land transport and shipping shared
74 and 12 % of the global CO2 emissions from transport in
the year 2000, respectively. In the time period 1990–2007,
the EU-15 CO2-equivalent emissions from land transport and
shipping increased by 24 and 63 %, respectively. This growth
is expected to continue in the future, due to increasing world
population, economic activities and related mobility. The future
road traffic scenarios analyzed by Uherek et al. (2010)
essentially agree in projecting an increase of both fuel demand
and CO2 emissions until 2030, with up to a factor of
∼ 3 increase in CO2 emissions with respect to 2000. The ATTICA
assessment also showed that emissions of CO2 from
land transport and shipping affect the global climate by exerting
a radiative forcing (RF) effect of 171 (year 2000)
and 37 mW m−2
(year 2005), respectively. These two sectors
together account for 13 % of the total anthropogenic CO2
warming (year 2005).
In addition to long-lived greenhouse gases, ground-based
vehicles and ocean-going ships emit aerosol particles as well
as a wide range of short-lived gases, including also aerosol
precursor species. Atmospheric aerosol particles have significant
impacts on climate, through their interaction with solar
radiation and their ability to modify cloud microphysical
and optical properties (Forster et al., 2007). In populated areas,
they also affect air quality and human health (Pope and
Dockery, 2006; Chow et al., 2006).
Prediction of pollutants emissions dispersion of phosphate fertilizers produc...eSAT Journals
Abstract This study aims to the prediction of pollutants emissions dispersion of a 1 M·ton/year phosphate fertilizer facility, which is located at El-Menya Governorate, Egypt. ALOHA air dispersion software is used to predict the pollutant emissions dispersion from different stacks in the proposed project. The estimated total pollutant emissions from the proposed project are 3180 g/m3 of hydrogen fluoride (HF), 72000 g/m3 of sulfur dioxide (SO2), 14700 g/m3 of sulfur tri-oxide (SO3), 2700 g/m3 of ammonia (NH3), and 53550 g/m3 of particulates (PM). Based on the total pollutant emissions from the project, the concentrations of the investigated pollution emissions at 0.5 km, 1 km and 2 km downstream the source at the worst case scenario are obtained and compared with the allowed limits. It has been found that all the emissions resulted from different activities in the proposed project are much lower than the allowed limits specified by the Egyptian ministry of environment in Law 4/1994, and therefore the proposed project is not expected to cause any undesirable impacts on the surrounding environment. Index Terms: Air pollution; Air dispersion modeling; Environmental impact assessment; Phosphate fertilizer industry.
This paper compares AERMOD with CALINE3-based models (CALINE4) and RLINE (Snyder and Heist, 2013) using a field study conducted in downtown Los Angeles in 2008. The evaluation supports the proposed replacement when AERMOD is executed with onsite meteorological data.
Characterization and the Kinetics of drying at the drying oven and with micro...Open Access Research Paper
The objective of this work is to contribute to valorization de Nephelium lappaceum by the characterization of kinetics of drying of seeds of Nephelium lappaceum. The seeds were dehydrated until a constant mass respectively in a drying oven and a microwawe oven. The temperatures and the powers of drying are respectively: 50, 60 and 70°C and 140, 280 and 420 W. The results show that the curves of drying of seeds of Nephelium lappaceum do not present a phase of constant kinetics. The coefficients of diffusion vary between 2.09.10-8 to 2.98. 10-8m-2/s in the interval of 50°C at 70°C and between 4.83×10-07 at 9.04×10-07 m-8/s for the powers going of 140 W with 420 W the relation between Arrhenius and a value of energy of activation of 16.49 kJ. mol-1 expressed the effect of the temperature on effective diffusivity.
Micro RNA genes and their likely influence in rice (Oryza sativa L.) dynamic ...Open Access Research Paper
Micro RNAs (miRNAs) are small non-coding RNAs molecules having approximately 18-25 nucleotides, they are present in both plants and animals genomes. MiRNAs have diverse spatial expression patterns and regulate various developmental metabolisms, stress responses and other physiological processes. The dynamic gene expression playing major roles in phenotypic differences in organisms are believed to be controlled by miRNAs. Mutations in regions of regulatory factors, such as miRNA genes or transcription factors (TF) necessitated by dynamic environmental factors or pathogen infections, have tremendous effects on structure and expression of genes. The resultant novel gene products presents potential explanations for constant evolving desirable traits that have long been bred using conventional means, biotechnology or genetic engineering. Rice grain quality, yield, disease tolerance, climate-resilience and palatability properties are not exceptional to miRN Asmutations effects. There are new insights courtesy of high-throughput sequencing and improved proteomic techniques that organisms’ complexity and adaptations are highly contributed by miRNAs containing regulatory networks. This article aims to expound on how rice miRNAs could be driving evolution of traits and highlight the latest miRNA research progress. Moreover, the review accentuates miRNAs grey areas to be addressed and gives recommendations for further studies.
"Understanding the Carbon Cycle: Processes, Human Impacts, and Strategies for...MMariSelvam4
The carbon cycle is a critical component of Earth's environmental system, governing the movement and transformation of carbon through various reservoirs, including the atmosphere, oceans, soil, and living organisms. This complex cycle involves several key processes such as photosynthesis, respiration, decomposition, and carbon sequestration, each contributing to the regulation of carbon levels on the planet.
Human activities, particularly fossil fuel combustion and deforestation, have significantly altered the natural carbon cycle, leading to increased atmospheric carbon dioxide concentrations and driving climate change. Understanding the intricacies of the carbon cycle is essential for assessing the impacts of these changes and developing effective mitigation strategies.
By studying the carbon cycle, scientists can identify carbon sources and sinks, measure carbon fluxes, and predict future trends. This knowledge is crucial for crafting policies aimed at reducing carbon emissions, enhancing carbon storage, and promoting sustainable practices. The carbon cycle's interplay with climate systems, ecosystems, and human activities underscores its importance in maintaining a stable and healthy planet.
In-depth exploration of the carbon cycle reveals the delicate balance required to sustain life and the urgent need to address anthropogenic influences. Through research, education, and policy, we can work towards restoring equilibrium in the carbon cycle and ensuring a sustainable future for generations to come.
WRI’s brand new “Food Service Playbook for Promoting Sustainable Food Choices” gives food service operators the very latest strategies for creating dining environments that empower consumers to choose sustainable, plant-rich dishes. This research builds off our first guide for food service, now with industry experience and insights from nearly 350 academic trials.
UNDERSTANDING WHAT GREEN WASHING IS!.pdfJulietMogola
Many companies today use green washing to lure the public into thinking they are conserving the environment but in real sense they are doing more harm. There have been such several cases from very big companies here in Kenya and also globally. This ranges from various sectors from manufacturing and goes to consumer products. Educating people on greenwashing will enable people to make better choices based on their analysis and not on what they see on marketing sites.
Diabetes is a rapidly and serious health problem in Pakistan. This chronic condition is associated with serious long-term complications, including higher risk of heart disease and stroke. Aggressive treatment of hypertension and hyperlipideamia can result in a substantial reduction in cardiovascular events in patients with diabetes 1. Consequently pharmacist-led diabetes cardiovascular risk (DCVR) clinics have been established in both primary and secondary care sites in NHS Lothian during the past five years. An audit of the pharmaceutical care delivery at the clinics was conducted in order to evaluate practice and to standardize the pharmacists’ documentation of outcomes. Pharmaceutical care issues (PCI) and patient details were collected both prospectively and retrospectively from three DCVR clinics. The PCI`s were categorized according to a triangularised system consisting of multiple categories. These were ‘checks’, ‘changes’ (‘change in drug therapy process’ and ‘change in drug therapy’), ‘drug therapy problems’ and ‘quality assurance descriptors’ (‘timer perspective’ and ‘degree of change’). A verified medication assessment tool (MAT) for patients with chronic cardiovascular disease was applied to the patients from one of the clinics. The tool was used to quantify PCI`s and pharmacist actions that were centered on implementing or enforcing clinical guideline standards. A database was developed to be used as an assessment tool and to standardize the documentation of achievement of outcomes. Feedback on the audit of the pharmaceutical care delivery and the database was received from the DCVR clinic pharmacist at a focus group meeting.
DRAFT NRW Recreation Strategy - People and Nature thriving together
Implication of Applying CALPUFF to Demonstrate Compliance with the Regional Haze
1. Modeling Software for EHS Professionals
Implication of Applying CALPUFF to Demonstrate
Compliance with the Regional Haze Rule
Paper #651
Prepared By:
Weiping Dai, Ph.D.
Hung-Ming (Sue) Sung, Ph.D., P.E.
Curtis V. DeVore
BREEZE SOFTWARE
12700 Park Central Drive,
Suite 2100
Dallas, TX 75251
+1 (972) 661-8881
breeze-software.com
2. 1
Implication of Applying CALPUFF to Demonstrate
Compliance with the Regional Haze Rule
651
Weiping Dai, Ph.D.
Trinity Consultants, 12801 North Central Expressway, Suite 1200, Dallas, TX 75243
Hung-Ming (Sue) Sung, Ph.D., P.E.
Trinity Consultants, 12801 North Central Expressway, Suite 1200, Dallas, TX 75243
Curtis V. DeVore
Trinity Consultants, 12801 North Central Expressway, Suite 1200, Dallas, TX 75243
ABSTRACT
The U.S. Environmental Protection Agency promulgated the final Regional Haze Rule in July
1999 to protect Class I areas from visibility impairment. Industrial sources may be required to
conduct modeling analysis to demonstrate their potential impact on nearby Class I areas during
air permit applications. Although the widely used Industrial Source Complex Short-Term model
(ISCST3) can be applied (and it may be recommended as the first step screening tool by state
agencies), its results may not pass the strict criteria, which are set to protect the Class I areas.
Moreover, regional haze is generally a long-range transport phenomenon. Theoretically, the
ISCST3 model is not appropriate for a long-range transport (e.g., greater than 50 kilometers from
the emission sources). Variations of the meteorological and geophysical conditions in such a
distance require sophisticated temporal and spatial treatments of meteorological data,
geophysical data, and plume dispersions. The CALPUFF modeling system is designed to handle
long-range transport of various pollutants with consideration of chemical transformation.
For regional haze analysis, different states may have different modeling approach and guidance.
Colorado proposes a 3-tier approach: Tier 1 – ISCST3 modeling analysis; Tier 2 – CALPUFF
Screen analysis; and Tier 3 - Full CALPUFF analysis. CALPUFF Screen analysis is a simplified
approach with flat terrain assumption and meteorological data from one station. In this paper, a
case study of applying the CALPUFF modeling for regional haze analysis is conducted for an
industrial source with potential impact on a nearby Class I area. Results for a base case are
discussed and influences of several variables (e.g., distance between the source and the Class I
area, emission rates, stack parameters, and background ozone and ammonia concentrations) on
modeling results are evaluated. Modeling results indicate that control of NOX and SO2 is most
effective in reducing extinction change while stack parameters have small effects on extinction
change. Extinction change may also be a strong function of distance for distances less than
certain values (e.g., 80 km). In addition, it seems typical background ozone concentrations affect
the extinction change more than typical background ammonia concentrations.
3. 2
INTRODUCTION
The U.S. Environmental Protection Agency (USEPA) promulgated the final Regional Haze Rule
in July of 1999 in order to protect the 156 Class I areas from any future visibility impairment and
remedy any existing visibility impairment due to manmade air pollution.1
Class I Areas are
defined as national parks over 6,000 acres and wilderness areas and memorial parks over 5,000
acres in the Clean Air Act. According to the Regional Haze Rule, visibility impairment means
any humanly perceptible change in visibility (e.g., light extinction, visual range, contrast, and
coloration) from that which would have existed under natural conditions. Regional haze means
visibility impairment that is caused by the emissions of air pollutants from numerous sources
located over a wide geographic area. Such sources include, but are not limited to, major and
minor stationary sources, mobile sources, and area sources.
Visual air quality in Class I areas has been significantly degraded due to various anthropogenic
sources. The current visual range is only 30 – 90 miles in the West and 14 – 24 miles in the East
while the natural visual range should be approximately 140 miles in the west and 90 miles in the
east.2
Visibility impairment is primarily caused by the scattering and absorption of light due to
airborne fine particulate matter such as sulfates, nitrates, organic carbon, elemental carbon, and
soil dust. Ammonium sulfate and ammonium nitrate typically are secondary pollutants formed
from the oxidation of sulfur dioxide (SO2) and nitrogen oxides (NOX) in the presence of
ammonia gas (NH3) during processes of transport and dispersion. Anthropogenic sources emit
significant amount of SO2 and NOX.
For new source permit applications, applicants may be required to perform regional haze
analysis to assess the impact of emissions from the proposed sources on nearby Class I areas.
Several dispersion models such as VISCREEN, PLUVUE II, ISCST3, AERMOD, and
CALPUFF can be utilized for this modeling analysis purpose. Different states may have different
modeling analysis guidance. For example, Colorado recommends a 3-tier approach for long-
range transport modeling analysis: Tier 1 – ISCST3 modeling analysis; Tier 2 – CALPUFF
Screen analysis; and Tier 3 - Full CALPUFF analysis.3
CALPUFF Screen analysis is a simplified
approach with flat terrain assumption and meteorological data from one station. Although the
widely used ISCST3 can be applied (and it may be recommended as the first step screening tool
by state agencies), its results may not pass the strict criteria, which are set to protect the Class I
areas. Moreover, ISCST3 is not appropriate for long-range transport (e.g., greater than 50
kilometers from the emission sources) because variations of the meteorological and geophysical
conditions in such a distance require sophisticated temporal and spatial treatments of
meteorological data, geophysical data, and plume dispersions. Regional haze is generally a long-
range transport phenomenon. The CALPUFF modeling system is designed to handle long-range
transport of various pollutants with consideration of chemical transformation.
The CALPUFF modeling system consists of three major components: CALMET, CALPUFF,
and CALPOST.4
CALMET is a meteorological model for generating hourly three-dimensional
wind and temperature fields and various two-dimensional fields (mixing height, surface
characteristics, and dispersion properties) on a gridded modeling domain. These meteorological
fields developed by CALMET are used by CALPUFF. CALPUFF is a non-steady state transport
and dispersion model for calculating hourly pollutant concentrations and deposition fluxes at
selected receptors due to various emission sources. CALPOST is used to process the CALPUFF
4. 3
results for performing visibility, deposition, or concentration analysis for selected averaging
periods. Typically, a 24-hour averaging period is used for visibility analysis.
This study focuses on the application of full CALPUFF modeling analysis for regional haze
analysis. A case study is conducted for assessing the impact of SO2, NOX, and PM10 emissions
from a hypothetical industrial source on the nearby Class I area. Results for a base case are
discussed and influences of several variables (distance between the source and the Class I area,
emission rates, stack parameters, and background ozone and ammonia concentrations) on
modeling results are evaluated. Results from CALPUFF Screen analysis are also compared and
discussed. Finally, implication of applying ISCST3 and AERMOD for regional haze analysis is
also briefly discussed.
VISIBILITY ANALYSIS AND ANALYSIS THRESHOLDS
Visibility can be characterized by the light-extinction coefficient, which represents the
attenuation of light per unit distance (e.g., million meters [Mm]) due to scattering and absorption
by various chemicals such as ammonium sulfate, ammonium nitrate, soil, and other particulate
matter in the atmosphere. Visibility analysis is used to evaluate the extent of change of the
extinction coefficient in the areas of interest due to the emissions of various pollutants such as
SO2, NOX, and PM10. SO2 and NOX can be transformed to sulfate and nitrate during plume
transport and dispersion and then sulfate and nitrate combine with available ammonia in the
atmosphere to form ammonium sulfate [(NH4)2SO4] and ammonium nitrate (NH4NO3). The
change of extinction due to the emission source can be calculated as follows:
100
,
,
bext
sext
b
b
)Change (%Extinction , (1)
where bext,s is the extinction coefficient due to the emission source(s) and bext,b is the background
extinction coefficient under natural conditions. Note that the scattering and absorption of light by
gases also contribute to the light extinction coefficient. In general, bext,b is affected by various
background chemical species and the Rayleigh scattering phenomenon and can be calculated as
follows:5, 6
rayapcoarsesoilOCNOSObext bbbbbbbMmb
34
1
, )( , (2)
where )RH(fSO)(NH3b 4244SO , )RH(fNONH3b 343NO , OC4bOC , Soil1bsoil ,
MassCoarse6.0bcoarse , ]CarbonElemental[10bap , rayb Rayleigh scattering, )RH(f relative
humidity adjustment factor, and ][ concentration in g/m3
. Note that these chemical species
can be divided into two categories – hygroscopic chemicals [(NH4)2SO4 and NH4NO3] and non-
hygroscopic chemicals (organic carbon [OC], soil, coarse mass, and elemental carbon). Visibility
is normally much better in dry conditions than in wet conditions because fine particles absorb
moisture in the atmosphere and scatter light more efficiently due to the increased size.7
The
extinction due to hygroscopic chemicals is a function of the relative humidity factor, which has a
nonlinear relationship with the ambient relative humidity.
5. 4
The Draft Phase I Report of the Federal Land Managers’ Air Quality Related Values Workgroup
(FLAG) lists the site-specific background extinction under natural conditions for Class I areas.6
Note that many of the natural background extinction coefficients in Table 2.B-1 of the Draft
FLAG Report are in error. For example, all of the “Hygro” values for the eastern U.S. should be
0.9 Mm-1
, but some of them are incorrectly reported as 0.6 Mm-1
.
According to the guidance developed by FLAG, the following analysis thresholds of extinction
change due to sources located at least 50 km from the Class I areas will be applied in New
Source Review Visibility Analysis: (1) if the extinction change due to the proposed source is
greater than 10% for at least one modeled day, the federal land managers (FLM) will consider
the magnitude, frequency, duration, and other factors to assess the impact. However, the FLM is
likely to object to the issuance of the permit; (2) if the extinction change due to the proposed
source is less that 5% for all days, the FLM is not likely to object to the issuance of the permit;
(3) if the extinction change due to the proposed source is greater than 5% but less than 10%, a
cumulative analysis including the new source and all new source growth will be requested; (4) if
cumulative analysis results indicate that the effects from the combined sources are expected to
cause an extinction change less than 10% for all modeled 24-hour periods, the FLM is not likely
to object to the issuance of the permit; however, (5) if cumulative analysis results shows that the
cumulative extinction change is greater than 10% and the contribution from the proposed source
is not less than 0.4%, the FLM is likely to object to the issuance of the permit, even though the
magnitude, frequency, duration, and other factors will be considered.6
Note that the above
criteria are not yet final and may be revised in response to public comments.
In this study, three visibility-related pollutants (SO2, NOX, and PM10) are considered to be
emitted from a hypothetical industrial source. The SO2 and NOX are transformed to (NH4)2SO4
and NH4NO3 during transport and dispersion. Therefore, the chemicals with contribution to
visibility change are (NH4)2SO4, NH4NO3, and PM10. The extinction coefficient due to these
three chemicals (bext,s) can be expressed as follows:
PMNOSOsext bbbMmb
34
1
, )( , (3)
where )RH(fSO)(NH3b 4244SO , )RH(fNONH3b 343NO , and 10PM PM6.0b .
6. 5
CASE STUDY: EMISSION SOURCE AND MODELING SETUP
Hypothetical Industrial Source
In this study, it is assumed that a new industrial source is proposed to be built east of a Class I
area. The facility will emit SO2, NOX, and PM10 from a stack. Parameter values for a base case
are listed in Table 1. For the base case, the facility is approximately 50 km away from the closest
edge of the Class I area. The distance of 50 km is chosen because it is a general criterion distance
to distinguish near-field modeling from long-range transport modeling, although CALPUFF is
not technically subject to this criterion.
Table 1. Parameter Values for the Base Case
Parameter Value
Source UTM Coordinates Easting: 506 km
Northing: 4180 km
Zone: 13
Emission Rate SO2 (tons per year) 500
NOX (tons per year) 500
PM10 (tons per year) 500
Stack Parameter Stack Height (m) 100
Stack Diameter (m) 3
Exit Velocity (m/s) 15
Exit Temperature (K) 400
Background
Concentration
Ozone (ppb) 40
Ammonia (ppb) 10
CALPUFF Modeling Setup
Figure 1 shows the Class I area location and its surrounding terrain characteristics. A mountain
range is between the source and the Class I area. The terrain is quite flat near the source and the
terrain elevation increases as approaching the Class I area. Figure 2 shows the modeling domain
setup, the location of the source relative to the Class I area, and the placement of receptors. The
gray color scale represents the terrain elevation. The modeling domain contains a 45 25 grid
with a spacing of 4 km. Eight vertical layers are defined with the cell face heights at 20, 40, 100,
250, 500, 1000, 2000, and 3500 m.
In this study, CALMET is used to develop one year of gridded meteorological data in the
modeling domain. The input data includes four surface stations, two upper air stations, five
precipitation stations, geophysical data, and the prognostic wind field developed by the
Mesoscale Model with four-dimensional data assimilation (MM4). MM4 data are used as the
initial guess wind field. MM4 gridded prognostic wind field data are extracted from the 1990
National Climatic Data Center (NCDC) MM4 CDs. Appropriate values are chosen for input
7. 6
parameters such as interpolation and radius of influence of surface data, upper air data,
precipitation data, and terrain by judging the terrain characteristics and following
recommendations from available guidance documents.4, 5, 6
For CALPUFF modeling setup, six species (i.e., SO2, SO4, NOX, nitric acid (HNO3), NO3, and
PM10) are modeled. The MESOPUFF II chemical transformation scheme is used. The
background concentration is 40 ppb for ozone and 10 ppb for ammonia for the base case. The
default nighttime conversion rates are used (i.e., 0.2 %/hr for SO2 loss, 2 %/hr for NOX loss, and
2 %/hr for HNO3 gain). Gas-phase dry deposition is modeled for SO2, NOX, and HNO3.
Particulate-phase dry deposition is modeled for SO4, NO3, and PM10. Wet deposition is modeled
for SO2, SO4, HNO3, NO3, and PM10. Default dry and wet deposition parameter values are used.
Stacktip downwash, vertical wind shear above stack top, and partial plume penetration is
modeled with inversion strength computed from temperature gradients. Building downwash is
not considered in this study. Plumes are modeled as puffs with Pasquill-Gifford (PG) coefficients
for rural areas. When the lateral size of a plume exceeds 550 m, Heffter Equation is used to
switch from distance-dependent to time-dependent lateral dispersion coefficients.4
Puff splitting
is also allowed in this study. The partial plume path adjustment method is used with default
plume path coefficients. In this study, CALPOST is used to perform the extinction change
calculation with the CALPUFF output of hourly concentration and relative humidity.
Background concentrations for both the hygroscopic chemicals and the non-hygroscopic
chemicals are 0.54 g/m3
as (NH4)2SO4 and 5.06 g/m3
as soil, respectively. The background
extinction derived from these concentrations match the reference level for Class I areas in the
western U.S.6
Figure 1. Class I Area and Terrain Characteristics (the source is out of the view of this picture
to the east of the Class I area)
Class I Area
8. 7
Figure 2. CALPUFF Modeling Domain and Receptor Setup (Elevation increases as the shading
becomes darker.)
CASE STUDY: RESULTS AND DISCUSSION
Base Case Results
The base case has an emission rate of 500 tons per year (tpy) for each pollutant (SO2, NOX, and
PM10). Daily maximum extinction change (averaged over 24 hours) for the base case is shown in
Figure 3. All daily maximum extinction changes are below 3% except for four days. The highest
extinction change is 6.2% and there are two days have extinction change above 5%. In air permit
application, these results may result in request for accumulative analysis.
Three observations are made from the results. First, for the worst day, NOX contributes 58% to
the extinction while SO2 and PM10 contributes 35% and 7%, respectively. This implies that for
the same amount of emission, NOX contribute more than 1.5 times to the extinction change than
SO2 while SO2 contributes more than 8 times than PM10 under the modeling conditions. This is
reasonable because nitrate and sulfate oxidized from SO2 and NOX absorb moisture in the air and
form NH4NO3 and (NH4)2SO4 with available ammonia in the air and the oxidation of NOX is
typically faster than the oxidation of SO2. The NH4NO3 and (NH4)2SO4 aerosols scatter light
more effectively than PM10. Second, high extinction change typically occurs on the days with
high relative humidity (e.g., greater than 90%). This is reasonable because the relative humidity
factor increases dramatically for relative humidity higher than about 90%. Third, the visibility-
related pollutants can accumulate in the Class I area for more than one days and thus cause high
extinction change with the aid of relatively high relative humidity. For example, the highest
extinction change for the base case occurs at the second day of the accumulation with a relative
humidity of about 89%. Of course, the pollutant accumulation strongly depends on terrain
400 420 440 460 480 500 520 540 560 580
UTM Easting (km)
4,130
4,150
4,170
4,190
4,210
4,230
UTMNorthing(km)
9. 8
characteristics and wind patterns.
Figure 3. Daily Maximum Extinction Change for the Base Case
Sensitivity Analysis of Distance between Source and Class I Area
A sensitivity analysis is performed for distances of 30, 40, 50, 60, 70, 80, 90, and 100 km
between the source and Class I area. Note that the base elevation of the stack does not change for
these cases. Other parameter values are kept the same as those for the base case. The results are
presented in Figure 4.
The results show that as distance between the source and Class I area increases, the maximum
extinction change decreases. The rate of change increases when the source gets closer to the
Class I area and levels off for distances greater than 80 km. The maximum extinction change is
almost 11% for a distance of 30 km while the maximum extinction change is about 4% for
distances greater than 80 km. It seems distances less than 50 km a have significant impact on the
maximum extinction change. Moderate effects are expected for distances between 50 km and 80
km while the maximum extinction change becomes insensitive for distances greater than 80 km.
Note that the observations here may not be true for other cases due to the complicated nature of
many factors such as terrain effects.
0
1
2
3
4
5
6
7
1 30 59 88 117 146 175 204 233 262 291 320 349
Julian Day of 1990
ExtinctionChange(%)
10. 9
Figure 4. Effects of Distance on Maximum Extinction Change
Sensitivity Analysis of Emission Rate
A sensitivity analysis is performed by changing the emission rates of SO2, NOX, and PM10
separately from 100 tpy to 1500 tpy. Other parameter values are kept the same as the base case.
The results are presented in Figure 5.
The results show that the rate of maximum extinction change is approximately linear to the
change of the emission rate. Extinction change increases approximately 0.75% (note that this is
an absolute change of the extinction change) for an increase of 100 tpy for NOX, 0.44% for SO2,
and 0.09% for PM10. These results are quite consistent with the contributions of NOX, SO2, and
PM10 to the maximum extinction change shown in the base case. The results imply that reduction
in NOX emissions may be most effective for improving visibility quality, followed by reduction
in SO2 emissions under certain modeling conditions.
0
2
4
6
8
10
12
30 40 50 60 70 80 90 100
Distance (km)
ExtinctionChange(%)
Cases
5% Threshold
10% Threshold
11. 10
Figure 5. Effects of Emission Rates on Maximum Extinction Change
Sensitivity Analysis of Stack Parameters
A sensitivity analysis is performed by changing the stack height, stack exit temperature, and
stack exit velocity while other parameter values are kept the same as the base case. The results
are shown in Figures 6, 7, and 8. Stack height is changed from 40 to 120 m. Stack exit
temperature is changed from 300 to 500 K and stack exit velocity is changed from 5 to 25 m/s.
In general, individually increasing stack height, stack exit temperature, or stack exit velocity
decreases the maximum extinction change. However, the rate of decrease is small. On average,
the extinction change decreases about 0.06% for a 10-m increase of stack height and 0.14% for a
5 m/s increase of stack exit velocity. Changes in stack exit temperature seem to have a greater
impact on visibility change at the lower end of the investigated temperature range.
0
2
4
6
8
10
12
14
16
18
0 200 400 600 800 1000 1200 1400 1600
Emission Rates (tons per year)
ExtinctionChange(%)
SO2 Cases
NOX Cases
PM10 Cases
5% Threshold
10% Threshold
12. 11
Figure 6. Effects of Stack Height on Maximum Extinction Change
Figure 7. Effects of Stack Temperature on Maximum Extinction Change
4
6
8
10
12
40 60 80 100 120
Stack Height (m)
ExtinctionChange(%)
Cases
5% Threshold
10% Threshold
4
6
8
10
12
300 350 400 450 500
Stack Temperature (K)
ExtinctionChange(%)
Cases
5% Threshold
10% Threshold
13. 12
Figure 8. Effects of Stack Exit Velocity on Maximum Extinction Change
Sensitivity Analysis of Background Ozone and Ammonia Concentration
Background ozone and ammonia concentrations contribute to the visibility quality because these
two chemicals are involved in the chemical transformation of SO2 and NOX during transport and
dispersion. A sensitivity analysis is conducted by changing ozone concentration from 10 ppb to
100 ppb and changing ammonia concentration from 0.1 ppb to 20 ppb. Other parameter values
are kept the same as the base case. The results are presented in Figures 9 and 10. It seems that
change in background ozone concentration has noticeable impact on maximum extinction
change. On average, the maximum extinction change increases 0.26% for each 10-ppb increase
of ozone concentration. Results indicate that the maximum extinction change is relatively
insensitive to ammonia background concentration unless it is very low (e.g., 0.1-1 ppb).
4
6
8
10
12
5 10 15 20 25
Stack Exit Velocity (m/s)
ExtinctionChange(%)
Cases
5% Threshold
10% Threshold
15. 14
Other Considerations in Visibility Analysis
Quality Control of Modeled Wind Fields
CALMET output is the gridded meteorological data in an unformatted data file. In order to
confirm the reasonableness of the final wind fields developed by CALMET, hourly wind vector
plots are developed and visually evaluated for wind field characteristics such as downslope flow
during nighttime and upslope flow during daytime. Figure 11 presents an hourly wind vector plot
for demonstration purpose. The figure clearly shows the downslope flow and the wind vector
follows the terrain reasonably well.
Figure 11. Wind Vector Plots for Checking Final Modeled Wind Fields
Comparison of CALPUFF Screen Analysis and Full CALPUFF Analysis
The major difference between CALPUFF Screen analysis and full CALPUFF analysis is the way
to generate meteorological data and place receptors. Full CALPUFF analysis utilizes CALMET
to develop gridded meteorological data by using multiple meteorological (surface, upper air, and
precipitation) stations and accounting for terrain effects. CALMET can even make use of
sophisticated prognostic wind fields developed by other mesoscale models (e.g., MM4 and
MM5). In addition, receptors are placed only on the Class I Area of concern. However,
performing full CALPUFF analysis requires tremendous efforts and computer resources.
CALPUFF Screen analysis uses an ISC-type meteorological data from a single meteorological
data. It also assumes flat terrain. The conservatism in CALPUFF Screen analysis comes from the
placement of receptors. Instead of looking at receptors on the Class I area, rings of discrete
receptors (1-degree apart) are placed between the closest and farthest distance from the source to
the Class I area. Extinction change at each receptor is considered. This conservatism is based on
the fact that no terrain effects are taken into account and therefore no directional distinction
should be considered.
16. 15
Table 2 compares results from full CALPUFF analysis with those from CALPUFF Screen
analysis for the base case. The maximum extinction change from the Screen analysis is almost
three times higher than that from the full analysis. Moreover, the frequency exceeding the
threshold values (5% and 10%) significantly increases.
Table 2. Comparison of Results from CALPUFF Screen Analysis and Full CALPUFF Analysis
Parameter Full Analysis Screen Analysis
Maximum Extinction Change (%) 6.2 17.5
Days with Extinction Change > 5 % 2 50
Days with Extinction Change >10% 0 8
Application of ISCST3 or AERMOD for Visibility Analysis
Both ISCST3 and AERMOD are steady-state dispersion models. Theoretically, both ISCST3 and
AERMOD are not suitable for long-range transport modeling analysis. However, according to
Colorado modeling guidance, ISCST3 is acceptable as a screening step for long-range transport
modeling analysis even though it is also mentioned that the ISCST3 Screen Analysis may
eventually be replaced with the CALPUFF Screen.
Nevertheless, ISCST3 is the regulatory model for near-field (less than 50 km) analysis and
AERMOD is expected to be the replacement of ISCST3 in the future. Therefore, if it is desirable
to conduct visibility analysis for near-field sources, ISCST3 and AERMOD may be the options.
SUMMARY
This study has focused on performing full CALPUFF analysis for long-range transport regional
haze analysis. Extinction change can be affected by many factors (e.g., relative humidity,
distance between the emission source and Class I area, emission rates, stack parameters, and
background ozone and ammonia concentrations). Modeling results indicate that control of NOX
and SO2 is most effective in reducing extinction change while stack parameters have small
effects on extinction change. Extinction change may also be a strong function of distance for
distances less than certain values (e.g., 80 km). In addition, it seems typical background ozone
concentrations affect the extinction change more than typical background ammonia
concentrations.
17. 16
REFERENCES
1. U.S. Environmental Protection Agency, Regional Haze Regulations (Final Rule), Federal
Register, Vol. 63, No. 126, July 1, 1999, pp.35714-35774.
2. U.S. Environmental Protection Agency, Fact Sheet: Final Regional Haze Regulations for
Protection of Visibility in National Parks and Wilderness Areas, June 2, 1999.
3. Colorado Department of Public Health and Environment, Long-Range Transport Model
Selection and Application, Air Pollution Control Division/Technical Services Program, May
21, 1999.
4. Earth Tech Inc., A User’s Guide for the CALPUFF Dispersion Model, Concord, MA, May
1999.
5. Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 2 Summary Report and
Recommendations for Modeling Long Range Transport, U.S. EPA, Office of Air Quality
Planning and Standards, EPA-454/R-98-019, December 1998.
6. U.S. Forest Service – Air Quality Program, National Park Service – Air Resources Division,
U.S. Fish and Wildlife Service – Air Quality Branch, Draft Phase I Report of the Federal
Land Managers’ Air Quality Related Values Workgroup (FLAG), October 1999.
7. N.D. Nevers, Air Pollution Control Engineering, McGraw-Hill, 1995, p506.