Air Quality Data

Welcome to Vermont's Real-Time Air Quality Data

The Home Page displays a map of Vermont with the stationary monitoring site locations indicated by color coded boxes and links to various graphical data for the past 5 days:

The number in the box represents the most recent hour's AQI value for each site. The background color of the box is based on the EPA AQI value. (i.e. green=good).

  • AQI is the “Air Quality Index.” It tells how clean or polluted the ambient air is, and what associated health effects might be of concern. The AQI focuses on short term health effects. The EPA calculates the AQI for five major air (Criteria) pollutants regulated by the Clean Air Act: ground-level ozone, particle pollution (also known as particulate matter), carbon monoxide, sulfur dioxide, and nitrogen dioxide. AQI is defined in detail at the website 

Hovering the cursor over the site box will display all of the most recent hour's pollutants values. The “Responsible Pollutant” is listed at the top and is the pollutant currently defining the calculated AQI the current highest relative concentration.

The site boxes are also links. Click on a site box to bring up the Site Display page. *Note: To go back to the main page, use the back button under the ‘Site Display’ title, or use your browser’s back button.

  • The "Layers" drop-down menu above the map can be used to select and display the most recent ambient air concentration of pollutants monitored at the sites (not all pollutants are monitored at all sites). 
  • The Site Display page shows the physical site address, a picture of the site monitoring trailer, and a list of parameters measured at that site.
  • Below the site picture is a link to Real-Time & Historical Data Concentration. This opens a page with real-time graphical & tabular views of today’s hourly data at that site. Past days can be viewed by selecting a different date at the top of the page and clicking  ‘Load.’ (*Note: Hit the back button in the web browser to go back to the Site Display page.)
  • The table at the bottom of this Site Display page shows the AQI values for the past 6 hours, and the responsible pollutant that is defining the AQI for that hour.

​To view the Vermont forcasted AQI: click onVermont AQI Forecast on AirNow.

To sign up and receive daily email alerts on Air Quality Index: click onEnviroFlash.

Meteorological Pollutant Name Description
AMBTEMP Ambient Temperature  
BARPRESS Barometeric Pressure  
RAINFALL Precipitation/ Rainfall  
REL_HUM Relative Humidity  
SIGAM_TH Sigma Theta Is the standard deviation of both wind speed & wind direction.
SOL_RAD Solar Radiation  
WDVEC Wind Direction Scalar Scalar
WDVEC Wind Direction Vector  
WSSCAL Wind Speed Scalar  
WDSCAL Wind Direction Scalar