(a) What is the purpose of this section? This section establishes procedures for addressing the excessive buildup of certain air pollutants during periods of stagnant air. This section is intended to prevent the occurrence of an air pollution emergency within the Indian reservation due to the effects of these air pollutants on human health.

(b) Who is affected by this section? This section applies to the Regional Administrator and any person who owns or operates an air pollution source within the Indian reservation.

(c) What are the requirements of this section?—(1) Air pollution action level triggers. Conditions justifying the declaration of an air pollution alert, air pollution warning, or air pollution emergency exist whenever the Regional Administrator determines that the accumulation of air pollutants in any place is approaching, or has reached, levels that could lead to a threat to human health. The following criteria will be used for making these determinations:

(i) Air stagnation advisory. An air stagnation advisory may be issued by the Regional Administrator whenever meteorological conditions over a large area are conducive to the buildup of air pollutants.

(ii) Air pollution alert. An air pollution alert may be declared by the Regional Administrator when any one of the following levels is reached, or is projected to be reached, at any monitoring site and the meteorological conditions are such that the level is expected to continue or reoccur over the next 24 hours.

(A) Particulate matter (PM10): 350 micrograms per cubic meter, 24-hour average;

(B) Carbon monoxide (CO): 17 milligrams per cubic meter (15 ppm), 8-hour average;

(C) Sulfur dioxide (SO2): 800 micrograms per cubic meter (0.3 ppm), 24-hour average;

(D) Ozone (O3): 400 micrograms per cubic meter (0.2 ppm), 1-hour average;

(E) Nitrogen dioxide (NO2): 1,130 micrograms per cubic meter (0.6 ppm), 1-hour average; and 282 micrograms per cubic meter (0.15 ppm), 24-hour average.

(iii) Air pollution warning. An air pollution warning may be declared by the Regional Administrator when any one of the following levels is reached, or is projected to be reached, at any monitoring site and the meteorological conditions are such that the level is expected to continue or reoccur over the next 24 hours.

(A) Particulate matter (PM10): 420 micrograms per cubic meter, 24-hour average;

(B) Carbon monoxide (CO): 34 milligrams per cubic meter (30 ppm), 8-hour average;

(C) Sulfur dioxide (SO2): 1,600 micrograms per cubic meter (0.6 ppm), 24-hour average;

(D) Ozone (O3): 800 micrograms per cubic meter (0.4 ppm), 1-hour average;

(E) Nitrogen dioxide (NO2): 2,260 micrograms per cubic meter (1.2 ppm), 1-hour average; and 565 micrograms per cubic meter (0.3 ppm), 24-hour average.

(iv) Air pollution emergency. An air pollution emergency may be declared by the Regional Administrator when any one of the following levels is reached, or is projected to be reached, at any monitoring site and the meteorological conditions are such that the level is expected to continue or reoccur over the next 24 hours.

(A) Particulate matter (PM10): 500 micrograms per cubic meter, 24-hour average;

(B) Carbon monoxide (CO): 46 milligrams per cubic meter (40 ppm), 8-hour average;

(C) Sulfur dioxide (SO2): 2,100 micrograms per cubic meter (0.8 ppm), 24-hour average;

(D) Ozone (O3): 1,000 micrograms per cubic meter (0.5 ppm), 1-hour average;

(E) Nitrogen dioxide (NO2): 3,000 micrograms per cubic meter (1.6 ppm), 1-hour average; and 750 micrograms per cubic meter (0.4 ppm), 24-hour average.

(v) Termination. Once declared, an air pollution alert, warning, or emergency will remain in effect until the Regional Administrator makes a new determination and declares a new level.

(2) Announcements by the Regional Administrator. The Regional Administrator will request that announcement of an air stagnation advisory, air pollution alert, air pollution warning, or air pollution emergency be broadcast on local television and radio stations in the affected area and posted on their websites. Announcements will also be posted on the EPA Region 10 website and, where possible, on the websites of Tribes within the affected area. These announcements will indicate that air pollution levels exist that could potentially be harmful to human health and indicate actions that people can take to reduce exposure. The announcements will also request voluntary actions to reduce emissions from sources of air pollutants as well as indicate that a ban on open burning is in effect.

(3) Voluntary curtailment of emissions by sources. Whenever the Regional Administrator declares an air stagnation advisory, air pollution alert, air pollution warning, or air pollution emergency, sources of air pollutants will be requested to take voluntary actions to reduce emissions. People should refrain from using their wood-stoves and fireplaces unless they are their sole source of heat. People should reduce their use of motor vehicles to the extent possible. Industrial sources should curtail operations or switch to a cleaner fuel if possible.

(4) Mandatory curtailment of emissions by order of the Regional Administrator.

(i) Except for exempted fires set for cultural or traditional purposes, all open burning is prohibited whenever the Regional Administrator issues an air stagnation advisory or declares an air pollution alert, air pollution warning, or air pollution emergency. Except for exempted fires set for cultural or traditional purposes, all open burning is prohibited when a burn ban is declared pursuant to §49.131 General rule for open burning or the EPA-approved Tribal open burning rule.

(ii) Except for exempted fires set for cultural or traditional purposes, any person conducting open burning when such an advisory is issued or declaration is made must either immediately extinguish the fire, or immediately withhold additional material such that the fire burns down.

(iii) During an air pollution warning or air pollution emergency, the Regional Administrator may issue an order to any air pollution source requiring such source to curtail or eliminate the emissions.

(d) Definitions of terms used in this section. The following terms that are used in this section are defined in §49.123 General provisions: Air pollutant, air pollution source, ambient air, emission, fuel, motor vehicle, open burning, Regional Administrator, and source.