(a) It shall be unlawful for any person to purchase goods in quantities greater than those specified by the Mayor or the federal government during a public emergency declared pursuant to § 7-2304, or during an emergency resulting from a natural disaster declared pursuant to § 28-4102(b), if the Mayor or the federal government have declared said goods to be: (1) Necessary for first responders or others during a natural disaster or public emergency; (2) Necessary to maintain supply chains of commerce during a natural disaster or a public emergency; or (3) Subject to government-ordered rationing.