Table 1.

Summary of deposition data sources used in this study.

Name (period)	Spatial grain	Description	Source(s)
Pre-industrial (1800)	NA	constant N and S deposition assuming 0.4 kg N ha−1 yr−1 and 0.1 kg S ha−1 yr−1	Lamarque et al. 2010, Baron 2006; Holland et al. 1999; Galloway et al. 2004
Historical (1850–2000)	200 × 200 km	CAM modeled N and S deposition using EDGAR-HYDE inventory and CAM 3.5 atmospheric model, scaled to current.	Lamarque et al. 2010
Current (2002–2011)	12 × 12 km	modeled N and S deposition using SMOKE inventory and CMAQ 5.0.2 bidirectional model	Bash et al. 2013; Foley et al. 2016
Clean Air Act (CAA) reductions (2025)	12 × 12 km	modeled N and S deposition using CAA anticipated 2025 inventory and CMAQ 5.0.2 bidirectional model	Bash et al. 2013, EPA 2014, Robin Dennis, personal communication
CAA + fertilizer reductions (2025)	12 × 12 km	modeled N and S deposition using CAA anticipated 2025 inventory, 20% reduction (~0.2 Tg yr−1 reduction) in fertilizer application from 2000–2002 baseline, and CMAQ 5.0.2 bidirectional model	this study
CAA + livestock management (2025)	12 × 12 km	modeled N and S deposition using CAA anticipated 2025 inventory, 30% reduction (~0.7 Tg yr−1 reduction) of NH3 from livestock and concentrated animal feeding operations (CAFOs) relative to 1990 baseline, and CMAQ 5.0.2 bidirectional model	this study
CAA + fertilizer + livestock (2025)	12 × 12 km	modeled N and S deposition using CAA anticipated 2025 inventory, both fertilizer and livestock/CAFO reductions above, and CMAQ 5.0.2 bidirectional model	this study