Fig. 1.

(a) Estimated ammonia emissions (Gg/yr) from 2002 until 2030 from animal feeding operations; the data include cattle, swine, sheep, goat, and poultry. (b) The contribution (%) from each animal group using data from 2002. Adapted from USEPA (2004).


Fig. 2.

(a) Estimated N2O emissions (Gg/yr) from 1990 until 2020 from agricultural sources. (b) The contribution (%) from each source group using data from 2005. Adapted from USEPA (2006).


Fig. 3.

Map of nonattainment designations for 8-h ozone in the United States as of 16 Dec. 2008. Source: USEPA (2011c).