Discover the Arizona Town With the State’s Worst Air Quality

Written by Christina Eck
Updated: June 22, 2023
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Key Points:

  • The air quality index (AQI) is a numerical scale measuring air quality by factors including pollutants, ground-level ozone, carbon monoxide, sulfur, etc. 
  • The town of Tonto Basin was initially known for being the last stronghold of the Apache Indians – it’s now known for having the worst air quality in Arizona.
  • A combination of being located in a valley, mining operations, global warming, and an increase in population has contributed to the town’s poor air quality.

Nestled in the heart of Arizona, there is a small town with the highest air quality score in the state. While the thriving town is known for its stunning views, the air quality is starting to threaten the residents and wildlife’s health and well-being. Let’s take a closer look to discover the Arizona town with the state’s worst air quality.

In this article, we will delve deeper into this small town’s situation, how it became one of the worst air qualities in the state, and its consequences on the locals and environment. We will also examine what is being done to combat what is happening.

The Town With the Worst Air Quality in Arizona

Human hands holding lung organ symbol. Awareness of lung cancer, pneumonia, asthma, COPD, pulmonary hypertension, world no tobacco day and eco air pollution. Respiratory and chest concept.
Poor air pollution produces harmful gases and pollutants in the air that can cause viruses and bacteria in the lungs.

©Orawan Pattarawimonchai/

The state of Arizona has a handful of towns that have terrible air quality. However, one stands out, with a high rating according to the Air Quality Index. The town of Tonto Basin has become a cautionary tale of how climate change and pollution have impacted the lives of the townsfolk.

Tonto Basin is located in the foothills of Mazatzal Mountains in West Gila County. The town was initially known for being the last stronghold of the Apache Indians. However, it’s now holding the record of having the worst air quality in Arizona.

Tonto Basin Air Quality Score

Air quality index measurement
Negative effects can occur in some folks in regions with an AQI as low as 51.


Before looking at Tonto Basins’ air quality score, we must understand its calculation. The air quality index (AQI) is a numerical scale measuring air quality. The scale factors include pollutants, ground-level ozone, carbon monoxide, sulfur, etc. 

The formula works by measuring the amount of each type of pollutant and then converting it into an index value. That is then plugged into the United States Environmental Protection Agency’s (EPA) air quality index formula.

The result of this will be the AQI score that is used to determine air quality. AQI scales describe the air quality by numerical ranking. Here are the following scores and what they mean:

  • 0-5: Satisfactory and livable conditions. There is no risk of pollution or negative side effects.
  • 51-100: Acceptable air quality that only puts a few people at risk who are sensitive to air pollution.
  • 101-150: Sensitive groups will experience negative symptoms due to air pollution, but others will be healthy.
  • 151-200: The general public will experience negative health effects, and sensitive folks will experience long-term health issues.
  • 201-300: The risk of pollution is so high that all animals will experience negative effects.
  • 301+: Everyone will be affected and needs to evacuate.

Currently, Tonto Basin’s air quality score is 67.8. While this isn’t terrible, the number has been rising. If something isn’t done about Tonto Basin’s AQI, then there could be real consequences in the future. If Tonto Basin slips into the 101-150 AQI rating, the public, and surrounding animals will start to feel the effects.

How Tonto Basin Got the Worst Air Quality Index Score

Tonto National Forest
At nearly 68, Tonto Basin’s AQI is high compared to other areas in Arizona.


Tonto Basins’ air quality index score is exceptionally high compared to other areas in Arizona. Many believe that this is the cause of global warming. Despite their belief, it’s mainly due to the town’s unfortunate location.

Geographically, the town is located inside a valley that has mountain ranges. This is essential, as the basin will trap pollution due to the elevation. Since the pollution has nowhere to go, the air will stay stagnant and won’t dissipate.

The town is home to a few mining areas and industrial facilities. These factors have contributed mainly to the town’s pollution problem. Additionally, an increase in population has added additional pollution to the area via the use of more cars.

The Environmental Protection Agency has designed guidelines on how a town can avoid this matter. However, the local government has not stuck to its recommendations. 

Where is Tonto Basin Located on a Map?

Tonto Basin is located in the central region of Arizona – around 89 miles northeast of the city of Phoenix. It is close to the Tonto National Forest and less than 20 miles from Roosevelt Lake to its southeast.

Tonto Basin Human Population

Tonto Basin, AZ is located next to Tonto National Forest
Tonto Basin has the state’s worst air quality and is located new Tonto National Forest.

© Photography

As of 2023, Tonto Basin has a lowering population of 1,437, according to World Population Review. The community thrives off of agriculture, farming, and tourism. Due to the surrounding mountains, the city has plenty of nature to offer tourists. This makes the town a unique location for enthusiasts and those interested in outdoor activities.

However, the poor air quality will affect the resident’s health and well-being. It’s important to understand that high pollution levels can have lasting effects if consistently breathed in. Medical issues caused by poor air quality include chronic obstructive pulmonary disease (COPD), cancer, and other cardiovascular diseases.

The National Institute of Environmental Health Sciences has even detailed a handful of long-term consequences of ignoring air pollution. It affects not only the town’s population but also can affect visitors. Poor air quality and pollution have been proven to cause short-term effects such as pneumonia and bronchitis. 

Tonto Basin Wildlife

Mountain lions can reach 50 mph in short bursts.
Numerous predators, including mountain lions, call Tonto Basin and its surrounding areas home. So, if you’re there, be wary of them.


Tonto Basin is home to various animal species, including mammals, reptiles, and aquatic life. The town might be in a basin, but next to it is the Tonto National Forest, home to mountain lions, black bears, mule deer, and bobcats. There are also bald eagles, goshawks, and numerous native fish species.

Poor air quality can also affect wildlife by contaminating water sources and soil. Pollutants will settle into the dirt, which plants and foliage will absorb. Animals that eat these plants will ingest the contaminants.


Poor air quality in Tonto Basin is a concern every local should be worried about. Not only is it becoming a bigger problem as the basin traps more pollutants in the area, but it will also start affecting all life there. 

Luckily, efforts have been made to help address this issue. The government has enforced environmental regulations and pushed sustainable living practices in Tonto Basin. The residents will be the ones who can change this around by spreading ecological awareness.

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About the Author

Christina Eck is a freelance writer who has been working in the industry for the past five years. She has worked in multiple niches, specifically in the travel, product review, and mental health niche. She loves mental health and medical writing and plans to move into the medical writing niche in the future.

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