The Grand Canyon area has some of the cleanest air in the United States.

However, at times the air quality can be considerably affected by events such as forest fires and dust storms in the Southwest.

What effect there is on air quality and visibility in the canyon has been mainly from sulfates, soils, and organics.
The sulfates largely result from urban emissions in southern California, borne on the prevailing westerly winds throughout much of the year, and emissions from Arizona's copper smelter region, borne on southerly or southeasterly winds during the monsoon.
Airborne soils originate with windy conditions and road dust.
Organic particles result from vehicle emissions, long-range transport from urban areas, and forest fires, as well as from VOCs emitted by vegetation in the surrounding forests.
Nitrates, carried in from urban areas, stationary sources, and vehicle emissions; as well as black carbon from forest fires and vehicle emissions, also contribute to a lesser extent.

A number of actions have been taken to preserve and further improve air quality and visibility at the canyon.

In 1990, amendments to the Clean Air Act established the Grand Canyon Visibility Transport Commission (GCVTC) to advise the US EPA on strategies for protecting visual air quality on the Colorado Plateau.
The GCVTC released its final report in 1996 and initiated the Western Regional Air Partnership (WRAP), a partnership of state, tribal and federal agencies to help coordinate implementation of the Commission's recommendations.

In 1999, the Regional Haze Rule established a goal of restoring visibility in national parks and wilderness areas (Class 1 areas), such as the Grand Canyon, to natural background levels by 2064.
Subsequent revisions to the rule provide specific requirements for making reasonable progress toward that goal.

In the early 1990s, studies indicated that emissions of SO₂, a sulfate precursor, from the Navajo Generating Station affected visibility in the canyon mainly in the winter, and which if controlled would improve wintertime visibility by 2 to 7%.


As a result, scrubbers were added to the plant's three units in 1997 through 1999, reducing SO2 emissions by more than 90%.
The plant also installed low-NOₓ SOFA burners in 2009 -2011, reducing emissions of NOₓ, a nitrate precursor, by 40%.

Emissions from the Mohave Generating Station to the west were similarly found to affect visibility in the canyon.
The plant was required to have installed SO₂ scrubbers, but was instead shut down in 2005, completely eliminating its emissions.

Prescribed fires are typically conducted in the spring and fall in the forests adjacent to the canyon to reduce the potential for severe forest fires and resulting smoke conditions.
Although prescribed fires also affect air quality, the controlled conditions allow the use of management techniques to minimize their impact.
The Grand Canyon area has some of the cleanest air in the United States.
However, at times the air quality can be considerably affected by events such as forest fires and dust storms in the Southwest.
What effect there is on air quality and visibility in the canyon has been mainly from sulfates, soils, and organics. The sulfates largely result from urban emissions in southern California, borne on the prevailing westerly winds throughout much of the year, and emissions from Arizona's copper smelter region, borne on southerly or southeasterly winds during the monsoon. Airborne soils originate with windy conditions and road dust. Organic particles result from vehicle emissions, long-range transport from urban areas, and forest fires, as well as from VOCs emitted by vegetation in the surrounding forests. Nitrates, carried in from urban areas, stationary sources, and vehicle emissions; as well as black carbon from forest fires and vehicle emissions, also contribute to a lesser extent.
A number of actions have been taken to preserve and further improve air quality and visibility at the canyon.
In 1990, amendments to the Clean Air Act established the Grand Canyon Visibility Transport Commission (GCVTC) to advise the US EPA on strategies for protecting visual air quality on the Colorado Plateau. The GCVTC released its final report in 1996 and initiated the Western Regional Air Partnership (WRAP), a partnership of state, tribal and federal agencies to help coordinate implementation of the Commission's recommendations.
In 1999, the Regional Haze Rule established a goal of restoring visibility in national parks and wilderness areas (Class 1 areas), such as the Grand Canyon, to natural background levels by 2064. Subsequent revisions to the rule provide specific requirements for making reasonable progress toward that goal.
In the early 1990s, studies indicated that emissions of SO₂, a sulfate precursor, from the Navajo Generating Station affected visibility in the canyon mainly in the winter, and which if controlled would improve wintertime visibility by 2 to 7%.

As a result, scrubbers were added to the plant's three units in 1997 through 1999, reducing SO2 emissions by more than 90%. The plant also installed low-NOₓ SOFA burners in 2009 -2011, reducing emissions of NOₓ, a nitrate precursor, by 40%.
Emissions from the Mohave Generating Station to the west were similarly found to affect visibility in the canyon. The plant was required to have installed SO₂ scrubbers, but was instead shut down in 2005, completely eliminating its emissions.
Prescribed fires are typically conducted in the spring and fall in the forests adjacent to the canyon to reduce the potential for severe forest fires and resulting smoke conditions. Although prescribed fires also affect air quality, the controlled conditions allow the use of management techniques to minimize their impact.
Grand Canyon