Trends in wet precipitation, particulate, and gas-phase species in New York State

Abstract Here we characterized wet deposition National Atmospheric Deposition Program (NADP) species and Clean Air Status and Trends Network (CASTNET) dry deposited particle and gas species across New York over the last 2-3 decades. In addition measurements of NH 3 from the Ammonia Monitoring Network (AMoN) were analyzed. In general decreasing annual trends are observed for wet deposition SO 4 2− and NO 3 − species and dry deposited particle SO 4 2− , NO 3 − and NH 4 + as well as gas phase SO 2 and HNO 3 consistent with reductions in SO 2 and NO x emissions. Wet deposited NH 4 + however does not show consistent trends with most sites showing little trend across the region and an indication that levels at some sites maybe increasing. NH 3 concentrations also appear to be increasing although the data record is only 8 years. Base cations, Ca 2+ and Mg 2+ show some decreases in the 1980s but concentrations are relatively uniform since the mid-1990s. Na + and K + show large year to year variations, by more than an order of magnitude for Na + due to influence of marine air at a near coastal site. In general there was a balance between the sum of cations and the sum of anions earlier in the record but the tendency has been for a cation excess in the more recent 5–10 years. Understanding the deposition of reduced nitrogen species is likely to be of concern for the foreseeable future. Such data are important in understanding acidification recovery in response to emission controls.