Lake and bulk sampling chemistry, NADP, and IMPROVE air quality data analysis on the Bridger-Teton National Forest (USFS Region 4)

Air quality monitoring data from several programs in and around the Bridger-Teton (B-T) National Forest—National Atmospheric Deposition Program (NADP), longterm lake monitoring, long-term bulk precipitation monitoring (both snow and rain), and Interagency Monitoring of Protected Visual Environments (IMPROVE)— were analyzed in this report. Trends were analyzed using non-parametric tests and seasonality was taken into account when possible. Nitrate (NO3 -) showed seasonal increasing trends in all sampled lake inlets, in atmospheric deposition at NADP sites and bulk sampling sites, and at two visibility sites. NADP sites showed consistent decreasing trends for both deposition and concentrations in SO4 2-, Na+, Mg2+, and Cland increasing trends in NH4 + and inorganic nitrogen deposition. Lake and bulk deposition chemistry data showed increasing trends in cations and decreasing trends in Cl-. Bulk deposition sites showed an increasing trend in NH4 +. Standard Visual Range (SVR) showed an increasing trend and extinction showed a decreasing trend at all IMPROVE sites analyzed. In conclusion, considerations were listed regarding current and future air quality monitoring on the B-T National Forest.