The Department of Natural Resources proposed to amend Mo. Code Regs. tit. 10, §10.6.010. Changes would update the standards for ambient air quality in order to reflect changes in NAAQS. A public hearing will be held on January 30, 2014, and the deadline for comment is February 6, 2014. See http://www.sos.mo.gov/adrules/moreg/current/v38n24/v38n24.pdf (pp. 2089-2092).