Assessing long-term monitoring programs for sulfur, nitrogen, and mercury deposition and impacts in New York state

Background/Question/Methods

Air pollutants such as nitrogen oxides, sulfur dioxide, and mercury have had significant impacts on the quality of lakes, rivers, soils, biota, and tree health throughout the Northeastern US. Some areas of New York State are particularly susceptible to environmental degradation, such as the Adirondack and Catskill regions, which receive some of the highest rates of acid and mercury deposition in the country. Long-term monitoring (LTM) efforts have produced data sets that have been extremely valuable for evaluating changes over time in air pollution loads and effects on the environment. 

It is important to reevaluate LTM programs to ensure that these programs remain efficient and effective. To our knowledge, a comprehensive evaluation of state-wide long-term monitoring of acid and mercury deposition has never been undertaken in New York State. These monitoring efforts include projects funded by a variety of federal and state agencies, private non-profit organizations, and academic institutions. We have done a statistical analysis of select data sets to address the efficiency of monitoring efforts by identifying redundancies and gaps in monitoring efforts. These analyses include estimates of uncertainty in measurement and model parameters in order to most successfully answer key science and policy questions. 

Results/Conclusions

In some cases, we were able to identify redundancies in monitoring efforts, particularly with regard to acid deposition and Adirondack lakes. In the case of deposition, we recommend that co-located monitoring stations be moved to optimize the geographic coverage of LTM efforts, co-locate monitoring stations with other LTM programs, or increase monitoring intensity in locations where little data has been collected previously (ie. at high elevation sites). When assessing lake monitoring programs, we found that grouping lakes by physical and chemical characteristics allowed us to decrease the number of lakes sampled annually while still achieving a similar level of confidence in trend analyses relative to the current sampling scheme.

In the case of mercury monitoring, we found that current monitoring programs provide data that is inadequate for detecting trends over time. This may be a result of the restricted scale of these studies, or in some cases as a result of inadequacies of analytical tools to measure mercury at low concentrations with precision.

In general, we recommend that LTM programs would be most benefited by co-locating monitoring programs so that deposition effects on ecosystems can be assessed by correlating results from the study of a variety of ecosystem components.