Ariz. Admin. Code § R18-2-220 - Air Pollution Emergency Episodes

A. Procedures shall be implemented by the Director in order to prevent the occurrence of ambient air pollutant concentrations which would cause significant harm to the health of persons, as specified in subsection (B)(4). The procedures and actions required for each stage are described in the Department's "Procedures for Prevention of Emergency Episodes," amended as of August 2018 (and no future edition), which is incorporated herein by reference and on file with the Department.

B. The following stages are identified by air quality criteria in order to provide for sequential emissions reductions, public notification and increased Department monitoring and forecast responsibilities. The declaration of any stage, and the area of the state affected, shall be based on air quality measurements and meteorological analysis and forecast.

1. A Stage I air pollution alert shall be declared when any of the alert level concentrations listed in subsection (B)(4) are exceeded at any monitoring site and when meteorological conditions indicate that there will be a continuance or recurrence of alert level concentrations for the same pollutant during the subsequent 24-hour period. If, 48 hours after an alert has been initially declared, air pollution concentrations and meteorological conditions do not improve, the warning stage control actions shall be implemented but no warning shall be declared, unless air quality has deteriorated to the extent described in subsection (B)(2).

2. A Stage II air pollution warning shall be declared when any of the warning level concentrations listed in subsection (B)(4) are exceeded at any monitoring site and when meteorological conditions indicate that there will be a continuance or recurrence of concentrations of the same pollutant exceeding the warning level during the subsequent 24-hour period. If, 48 hours after a warning has been initially declared, air pollution concentrations and meteorological conditions do not improve, the emergency stage shall be declared and its control actions implemented.

3. A Stage III air pollution emergency shall be declared when any of the emergency level concentrations listed in subsection (B)(4) are exceeded at any monitoring site and when meteorological conditions indicate that there will be a continuance or recurrence of concentrations of the same pollutant exceeding the emergency level during the subsequent 24-hour period.

4. Summary of emergency episode and significant harm levels:

Pollutant	Averaging Time	Alert	Warning	Emergency	Significant Harm
Carbon monoxide (mg/ m3)	1-hr	--	--	--	144
	4-hr	--	--	--	86.3
	8-hr	17	34	46	57.5
Nitrogen dioxide (µg/m3)	1-hr	1,130	2,260	3,000	3,750
	24-hr	282	565	750	938
Ozone (ppm)	1-hr	.2	.4	.5	.6
PM2.5 (µg/m3)	24-hr	140.5	210.5	280.5	350.5
PM10 (µg/m3)	24-hr	350	420	500	600
Sulfur dioxide (µg/m3)	24-hr	800	1,600	2,100	2,620

Notes

Ariz. Admin. Code § R18-2-220

Adopted effective May 14, 1979 (Supp. 79-1). Editorial correction, subsection (B), paragraph (2) (Supp. 80-1). Editorial correction, subsection (A) (Supp. 80-2). Former Section R9-3-219 repealed, new Section R9-3-219 adopted effective May 28, 1982 (Supp. 82-3). Former Section R9-3-219 renumbered without change as Section R18-2-219 (Supp. 87-3). Section R18-2-220 renumbered from R18-2-219 and amended effective September 26, 1990 (Supp. 90-3). Amended by final rulemaking at 25 A.A.R. 888, effective 5/18/2019.