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Models, Tools and Databases for Air Research


  • AERMOD Modeling System
    A steady-state plume model that incorporates air dispersion based on planetary boundary layer turbulence structure and scaling concepts, including treatment of both surface and elevated sources, and both simple and complex terrain.
  • Community Multi-scale Air Quality (CMAQ) Model
    CMAQ is an air quality model and software suite designed to model multiple pollutants at multiple scales. CMAQ allows regulatory agencies and state governments to evaluate the impact of air quality management decisions, and gives scientists the ability to probe, simulate, and understand chemical and physical interactions in the atmosphere.
  • Community-LINE Source (C-LINE) Model
    C-LINE is a web-based model that estimates emissions and dispersion of toxic air pollutants for roadways in the U.S. C-LINE is intended to support local communities and planners to get an initial assessment of near-source air quality impacts of transportation-related sources using national-scale input databases, and reduced-form modeling approaches.
  • EPAUS9R - An Energy Systems Database for use with the Market Allocation (MARKAL) Model
    The EPAUS9r is a regional database representation of the United States energy system. The database uses the MARKAL model. MARKAL is an energy system optimization model used by local and federal governments, national and international communities and academia. EPAUS9r represents energy supply, technology, and demand throughout the major sectors of the U.S. energy system.
  • Downscaler Model 
    The Downscaler Model combines daily ozone and particulate matter monitoring and modeling data from across the U.S. to provide improved fine-scale predictions of air quality in communities and other specific locales. 
    GLIMPSE is a decision support modeling tool being developed by EPA that will assist states with energy and environmental planning through the year 2050. Users of GLIMPSE can explore the impacts of energy technologies and policies on the environment.  
  • Human Exposure Model (HEM)
    The Human Exposure Model is used primarily for performing risk assessments for sources emitting air toxics to ambient air. The HEM only addresses the inhalation pathway of exposure, and is designed to predict risks associated with chemicals emitted into the ambient air (i.e., in the vicinity of an emitting facility but beyond the facility's property boundary). The HEM provides ambient air concentrations, as surrogates for lifetime exposure, for use with unit risk estimates and inhalation reference concentrations to produce estimates of cancer risk and noncancer hazard, respectively, for the air toxics modeled.
  • Microenvironment Tracker (MicroTrac)
    Microenvironment Tracker (MicroTrac) is a model that uses global positioning system (GPS) data to estimate time of day and duration that people spend in different microenvironments (e.g., indoors and outdoors at home, work, school).
  • MOtor Vehicle Emission Simulator (MOVES)
    EPA’s MOtor Vehicle Emission Simulator (MOVES) is a state-of-the-science emission modeling system that estimates emissions for mobile sources at the national, county, and project level for criteria air pollutants, greenhouse gases, and air toxics.
  • Parameters (PARAMS 1.1)
    Although over 50 indoor emission source models have been developed (Guo, 2002a), few are widely used in indoor exposure assessment. This imbalance is partially caused by the fact that many source models contain one or more parameters that are difficult to determine. This program is a step toward alleviating this problem by providing 30 methods for estimating some of the parameters in those source models. It is useful to those who develop or use indoor air quality (IAQ) and exposure models, and those who develop or use quantitative structure activity relationship (QSAR) models. In addition, many methods in this program are useful to researchers in areas other than indoor air quality. Users can benefit from this program in two ways: (1) it serves as a handy tool by putting commonly used methods in one place, and (2) it saves users’ time by taking over tedious calculations.
  • Positive Matrix Factorization 5.0 (EPA PMF 5.0)
    EPA PMF is a receptor model developed and distributed by ORD. The model uses ambient measurements (water, air, sediments) and estimated uncertainties in those measurements to infer emission sources types impacting samples and their contribution to the sample.
  • Spreadsheet-based Ecological Risk Assessment for the Fate of Mercury (SERAFM)
    SERAFM is a steady-state, process based mercury cycling model designed specifically to assist a risk assessor or researcher in estimating mercury concentrations in the water column, sediment, and fish tissue for a given water body for a specified watershed. SERAFM predicts mercury concentrations in these media for the species Hg0, HgII, and MeHg. 
  • Unmix 6.0
    Unmix is a receptor model that is distributed by ORD. The model uses ambient measurements to determine the number of source types and their impacts at a monitoring site. The Unmix algorithm is based on defining feasible solution space for the input data. This space is derived using edges or sample groups with relatively low impacts. These edges define source types which account for the majority of variability in the data.


  • Atmospheric Model Evaluation Tool (AMET)
    AMET helps in the evaluation of meteorological and air quality simulations.
  • Benchmark Dose Software (BMDS)
    EPA developed the Benchmark Dose Software (BMDS) as a tool to help estimate dose or exposure of a chemical or chemical mixture associated with a given response level. The methodology is used by EPA risk assessors and is fast becoming the world’s standard for dose-response analysis for risk assessments, including air pollution risk assessments.
  • BenMAP
    BenMAP is a Windows-based computer program that uses a Geographic Information System (GIS)-based to estimate the health impacts and economic benefits occurring when populations experience changes in air quality.
  • Community-Focused Exposure and Risk Screening Tool (C-FERST)
    C-FERST is an online tool developed by EPA in collaboration with stakeholders to provide access to resources that can be used with communities to help identify and learn more about their environmental health issues and explore exposure and risk reduction options.
  • Community Health Vulnerability Index
    EPA scientists developed a Community Health Vulnerability Index that can be used to help identify communities at higher health risk from wildfire smoke. Breathing smoke from a nearby wildfire is a health threat, especially for people with lung or heart disease, diabetes and high blood pressure as well as older adults, and those living in communities with poverty, unemployment and other indicators of social stress. Health officials can use the tool, in combination with air quality models, to focus public health strategies on vulnerable populations living in areas where air quality is impaired, either by wildfire smoke or other sources of pollution. The work was published in Environmental Science & Technology.
  • Critical Loads Mapper Tool
    The Critical Loads Mapper Tool can be used to help protect terrestrial and aquatic ecosystems from atmospheric deposition of nitrogen and sulfur, two pollutants emitted from fossil fuel burning and agricultural emissions. The interactive tool provides easy access to information on deposition levels through time; critical loads, which identify thresholds when pollutants have reached harmful levels; and exceedances of these thresholds.
  • EnviroAtlas
    EnviroAtlas provides interactive tools and resources for exploring the benefits people receive from nature or "ecosystem goods and services". Ecosystem goods and services are critically important to human health and well-being, but they are often overlooked due to lack of information. Using EnviroAtlas, many types of users can access, view, and analyze diverse information to better understand the potential impacts of various decisions.
  • EPA Air Sensor Toolbox for Citizen Scientists
    EPA's Air Sensor Toolbox for Citizen Scientists provides information and guidance on new low-cost compact technologies for measuring air quality. Citizens are interested in learning more about local air quality where they live, work and play. EPA's Toolbox includes information about: Sampling methodologies; Calibration and validation approaches; Measurement methods options; Data interpretation guidelines; Education and outreach; and Low cost sensor performance information.
  • ExpoFIRST
    The Exposure Factors Interactive Resource for Scenarios Tool (ExpoFIRST) brings data from EPA’s Exposure Factors Handbook: 2011 Edition (EFH) to an interactive tool that maximizes flexibility and transparency for exposure assessors. ExpoFIRST represents a significant advance for regional, state, and local scientists in performing and documenting calculations for community and site-specific exposure assessments, including air pollution exposure assessments.
  • EXPOsure toolbox (ExpoBox)
    This is a toolbox created to assist individuals from within government, industry, academia, and the general public with assessing exposure, including exposure to air contaminants, fate and transport processes of air pollutants and their potential exposure concentrations. It is a compendium of exposure assessment tools that links to guidance documents, databases, models, reference materials, and other related resources.
  • Federal Reference & Federal Equivalency Methods
    EPA scientists develop and evaluate Federal Reference Methods and Federal Equivalency Methods for accurately and reliably measuring six primary air pollutants in outdoor air. These methods are used by states and other organizations to assess implementation actions needed to attain National Ambient Air Quality Standards.
  • Fertilizer Emission Scenario Tool for CMAQ (FEST-C)
    FEST-C facilitates the definition and simulation of new cropland farm management system scenarios or editing of existing scenarios to drive Environmental Policy Integrated Climate model (EPIC) simulations.  For the standard 12km continental Community Multi-Scale Air Quality model (CMAQ) domain, this amounts to about 250,000 simulations for the U.S. alone. It also produces gridded daily EPIC weather input files from existing hourly Meteorology-Chemistry Interface Processor (MCIP) files, transforms EPIC output files to CMAQ-ready input files and links directly to Visual Environment for Rich Data Interpretation (VERDI) for spatial visualization of input and output files. The December 2012 release will perform all these functions for any CMAQ grid scale or domain.
  • Instruction Guide and Macro Analysis Tool for Community-led Air Monitoring 
    EPA has developed two tools for evaluating the performance of low-cost sensors and interpreting the data they collect to help citizen scientists, communities, and professionals learn about local air quality.
  • Integrated Climate and Land use Scenarios (ICLUS)
    Climate change and land-use change are global drivers of environmental change. Impact assessments frequently show that interactions between climate and land-use changes can create serious challenges for aquatic ecosystems, water quality, and air quality. Population projections to 2100 were used to model the distribution of new housing across the landscape. In addition, housing density was used to estimate changes in impervious surface cover.  A final report, datasets, the ICLUS+ Web Viewer and ArcGIS tools are available.
  • Indoor Semi-Volatile Organic Compound (i-SVOC)
    i-SVOC Version 1.0 is a general-purpose software application for dynamic modeling of the emission, transport, sorption, and distribution of semi-volatile organic compounds (SVOCs) in indoor environments. i-SVOC supports a variety of uses, including exposure assessment and the evaluation of mitigation options. SVOCs are a diverse group of organic chemicals that can be found in: Many are also present in indoor air, where they tend to bind to interior surfaces and particulate matter (dust).
    • Pesticides;
    • Ingredients in cleaning agents and personal care products;
    • Additives to vinyl flooring, furniture, clothing, cookware, food packaging, and electronics.
  • Municipal Solid Waste Decision Support Tool (MSW DST)Exit
    This tool is designed to aid solid waste planners in evaluating the cost and environmental aspects of integrated municipal solid waste management strategies. The tool is the result of collaboration between EPA and RTI International and its partners.
  • Optical Noise-Reduction Averaging (ONA) Program Improves Black Carbon Particle Measurements Using Aethalometers
    ONA is a program that reduces noise in real-time black carbon data obtained using Aethalometers. Aethalometers optically measure the concentration of light absorbing or “black” particles that accumulate on a filter as air flows through it. These particles are produced by incomplete fossil fuel, biofuel and biomass combustion. Under polluted conditions, they appear as smoke or haze.
  • RETIGO tool
    Real Time Geospatial Data Viewer (RETIGO) is a free, web-based tool that shows air quality data that are collected while in motion (walking, biking or in a vehicle). The tool helps users overcome technical barriers to exploring air quality data. After collecting measurements, citizen scientists and other users can import their own data and explore the data on a map.
  • Remote Sensing Information Gateway (RSIG)
    RSIG offers a new way for users to get the multi-terabyte, environmental datasets they want via an interactive, Web browser-based application. A file download and parsing process that now takes months will be reduced via RSIG to minutes.
  • Simulation Tool Kit for Indoor Air Quality and Inhalation Exposure (IAQX)
    IAQX version 1.1 is an indoor air quality (IAQ) simulation software package that complements and supplements existing indoor air quality simulation (IAQ) programs. IAQX is for advanced users who have experience with exposure estimation, pollution control, risk assessment, and risk management. There are many sources of indoor air pollution, such as building materials, furnishings, and chemical cleaners. Since most people spend a large portion of their time indoors, it is important to be able to estimate exposure to these pollutants. IAQX helps users analyze the impact of pollutant sources and sinks, ventilation, and air cleaners. It performs conventional IAQ simulations to calculate the pollutant concentration and/or personal exposure as a function of time. It can also estimate adequate ventilation rates based on user-provided air quality criteria. This is a unique feature useful for product stewardship and risk management.
  • Spatial Allocator
    The Spatial Allocator provides tools that could be used by the air quality modeling community to perform commonly needed spatial tasks without requiring the use of a commercial Geographic Information System (GIS).
  • Traceability Protocol for Assay and Certification of Gaseous Calibration Standards
    This is used to certify calibration gases for ambient and continuous emission monitors. It specifies methods for assaying gases and establishing traceability to National Institute of Standards and Technology (NIST) reference standards. Traceability is required under EPA ambient and continuous emission monitoring regulations.
  • Watershed Deposition Mapping Tool (WDT)
    WDT provides an easy to use tool for mapping the deposition estimates from CMAQ to watersheds to provide the linkage of air and water needed for TMDL (Total Maximum Daily Load) and related nonpoint-source watershed analyses.
  • Visual Environment for Rich Data Interpretation (VERDI)
    VERDI is a flexible, modular, Java-based program for visualizing multivariate gridded meteorology, emissions, and air quality modeling data created by environmental modeling systems such as CMAQ and the Weather Research and Forecasting (WRF) model.


  • Air Quality Data for the CDC National Environmental Public Health Tracking Network 
    EPA's Exposure Research scientists are collaborating with the Centers for Disease Control and Prevention (CDC) on a CDC initiative to build a National Environmental Public Health Tracking (EPHT) network. Working with state, local and federal air pollution and health agencies, the EPHT program is facilitating the collection, integration, analysis, interpretation, and dissemination of data from environmental hazard monitoring, and from human exposure and health effects surveillance. These data provide scientific information to develop surveillance indicators, and to investigate possible relationships between environmental exposures, chronic disease, and other diseases, that can lead to interventions to reduce the burden of theses illnesses. An important part of the initiative is air quality modeling estimates and air quality monitoring data, combined through Bayesian modeling that can be linked with health outcome data.
  • EPAUS9R - An Energy Systems Database for use with the Market Allocation (MARKAL) Model
    The EPAUS9r is a regional database representation of the United States energy system. The database uses the MARKAL model. MARKAL is an energy system optimization model used by local and federal governments, national and international communities and academia. EPAUS9r represents energy supply, technology, and demand throughout the major sectors of the U.S. energy system.
  • Fused Air Quality Surfaces Using Downscaling
    This database provides access to the most recent O3 and PM2.5 surfaces datasets using downscaling.
  • Health & Environmental Research Online (HERO)
    HERO provides access to scientific literature used to support EPA’s integrated science assessments, including the  Integrated Science Assessments (ISA) that feed into the National Ambient Air Quality (NAAQS) reviews.
  • SPECIATE 4.5 Database
    SPECIATE is a repository of volatile organic gas and particulate matter (PM) speciation profiles of air pollution sources.