New York State collects hourly SO₂ data at four locations in the Adirondacks as part of the monitoring network established after the NYS Acid Deposition Control Act was signed in 1984.  The three plus decades of SO₂ data have shown consistent declines in concentration well correlated with reductions in emissions both within and upwind of New York State.  One recent result of this decrease is that the continuous monitoring method is now inadequate in rural areas.  Continuous SO₂ analyzers were designed to produce data that can be compared to the higher concentrations relevant for the NAAQS.  Features such as auto zeroing were not implemented for these instruments and EPA regulations do not permit post adjusting data to remove signal drift. 

We will present data trends and spatial and temporal comparisons including diurnal profiles of the hourly SO₂ data.  We will also compare the integrated hourly data to the weekly CASTNET data collected at NYSDEC monitoring sites. Lastly, we will attempt to determine if the continuous data or the integrated CASTNET data can better meet the needs of the air quality data user community in the future.