In this project, I intended to gain evidence that reduction in wet deposition of sulfate (SO4 2-) and nitrate (NO3 - ), resulting from implementation of the 2007 Heavy-Duty Highway Rule, had led to an increase in pH levels of surface waters in New York State. Currently, some surface waters in New York State, especially in the Adirondack and Catskill regions, have pH levels low enough to damage aquatic ecosystems. The purpose of the 2007 Heavy-Duty Highway Rule is to both reduce sulfur (S) content in highway diesel fuel as well as reduce nitrogen oxide (NOx) emissions from mobile sources. Reduction of NOx is accomplished by allowing new heavy-duty diesel vehicles to make use of advanced pollution control technologies such as high-efficiency catalytic exhaust emission control devices which could not previously be used since S damages these devices. S and NOx are precursors to acid deposition.
This project uses weekly data of SO4 2-, NO3 - , and pH concentrations over time from all active National Atmospheric Deposition Program (NADP) monitoring stations in New York State. Through regression analysis, I found that I cannot claim that the 2007 Heavy-Duty Highway Rule had any effect on concentrations of SO4 2-, NO3 - , or hydrogen ions (H+) at the 95% confidence level. Since H+ is directly related to pH, I also cannot claim that the 2007 Heavy-Duty Highway Rule and any effect on pH levels of surface waters in New York State at the 95% confidence level. If the 2007 Heavy-Duty Highway Rule does have any effect on pH levels of surface waters in New York State, more data and additional analysis will need to be conducted to confirm this
Department, Program, or Center
Department of Science Technology and Society/Public Policy (CLA)
RIT – Main Campus
Comer, Bryan, "Effect of the 2007 Heavy-Duty Highway Rule on pH Levels of Surface Waters in New York State" (2009). Accessed from