Data Analysis Tools and Algorithms

This page provides access to air quality analysis tools and standard aggregation and calculation algorithms for analyzing and reconstructing aerosol mass and haze.


Haze Conversion Equations - Equations for converting visibility to light extinction and light extinction to deciview.

Aerosol Type Equations - Equations for calculating aerosol types, e.g. sulfate, organic, soil, from elemental concentrations.

Reconstructed Light Extinction Procedures - Procedure for reconstructing light extinction from dry aerosol measurements.

Relative Humidity Correction Factors - Correction factors for converting dry extinction values to ambient extinction and vise versa.

Group 10, 50, 90 Visibility Indices - Procedures for calculating Group 10, 50, 90 values from aerosol and haze data.

Calculating Regional Haze Baseline - Average haze condition over the 2000 to 2004 period.

Calculating Aerosol Data Completeness Statistics - Procedures for calculating the aerosol data collection statistics.


Aerosol Component and reconstructed Bext Tutorial (3.5 megs)  (pkzipped version 0.8 megs)- An Excel workbook with detailed instructions and samples for calculating the aerosol composite components and reconstructed light extinction from IMPROVE aerosol data.  In addition, methods for aggregating these data into seasonal averages and Group 90 and 10 statistics are provided.

Haze Trend Tutorial - An Excel workbook with example data for plotting and examining trends of the 20% best and worst haze days and the contribution to bext from the aerosol composite components.

Win Haze - A computer-imaging software program that simulates visual air quality differences of various scenes.  (NOTE:  scroll to the bottom of the linked page for instructions on how to download the software.)

Visual Plume - Illustrate visual effects of changes in source emissions, stack parameters, meteorology, view geometry, chemical and physical properties of a plume against a specific background.

Ambient Monitoring Data Analysis System (AMDAS) - AMDAS is a PC-based, user-friendly, menu driven program that provides air quality analysts and managers with easy "point and click" access to air quality data for browsing, preparing tabular and graphical summaries, and performing statistical analyses.  AMDAS currently includes features specifically designed for the analysis of meteorological and air quality data contained in EPA's Aerometric Information Retrieval System (AIRS).  AMDAS can be used to analyze meteorological data, routine air quality data (i.e., hourly ozone, oxides of nitrogen, carbon monoxide, etc.), speciated VOC and carbonyl compound data (i.e., PAMS data), and atmospheric particulate matter data, including PM10 and PM2.5 total mass and speciated sample data

Real-time Environmental Applications and Display System (READY) - READY is an online source of past, present, and future meteorological data, as well as an interactive trajectory and dispersion modeling server.  

Aerosol Inorganics Model (AIM) - Online version of Clegg S. L., Brimblecombe P. and Wexler A. S. chemical thermodynamic model of aerosols of composition H+- NH4+- Na+-SO42- -NO3-- Cl--H2O. The models enable the distribution of water and ions to be calculated between liquid, solid and vapour phases for ambient conditions (temperature, relative humidity) specified by the user.