DEEP: 1971 - Air Quality Monitoring Begins

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Environmental Accomplishments of the Past 40 Years

Air Quality Monitoring Begins
{TSP Sampler} In 1971, DEP began its first monitoring of air quality in the state.  This was done under requirements of the 1970 federal Clean Air Act, which mandated ambient measurement for six criteria pollutants.  Looking back in time, the first monitoring equipment was rather primitive.  The total suspended particle (TSP) monitor, shown to the right, was used to determine how much “dust” was in the air.  A mechanical timer and large pump was used to pull massive amounts of air through a filter for 24 hours.  The filter was then sent out to a laboratory to determine the weight of particles loaded onto the filter. This data was also used to determine if Connecticut violated the National Ambient Air Quality Standards (NAAQS).
{AQI Google Earth Overlay} Today, both the air monitoring instruments and the way we collect data look very different.  Most instrumentation is now controlled by an internal computer.  These instruments are configured and controlled with touch-screen menus or remotely through the Internet.  DEP currently collects over two million air quality data points each year, most from continuous instruments located at the 24 air monitoring sites in Connecticut.  Air quality data are submitted to EPA on an hourly basis to determine the Air Quality Index (AQI), an indicator of how healthy the air is to breathe.  Up to the hour AQI levels can be viewed on the EPA AIRNow web site or on the AQI Google Earth (above left).
  • 1958 - CT Department of Health began measuring total suspended particulates and lead  which has now decreased by nearly 99%).
  • 1971 - CTDEP began ambient monitoring in cooperation with local agencies; the network consisted of 54 sites.
  • 1973 - First trailers brought in to “re-vamp” the network improving efficiency; and included the first computerized sampling.
  • 1979 – The first of several revisions to the ozone NAAQS was made.  Pollution reduction programs have resulted in a significant reduction in the number of days exceeding the ozone standard.
  • 1987 - Ambient Dioxin Network was established at each municipal waste combustor.
  • 1992 – CTDEP begins monitoring for ozone precursor pollutants with the PAMS network.
  • 2010 – CTDEP maintains an extensive monitoring network.
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