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

© Mihai_Andritoiu/

Written by Hailey Pruett

Updated: July 5, 2023

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Minimizing pollutants in the air we breathe is essential for all life. Clean air is something many of us take for granted. An area’s air quality index can vary significantly depending on the number and levels of major pollutants present and the sources emitting them. Unfortunately, some towns have lower-quality air than others for various reasons. Below, we’ll take a look at the Maine town with the worst air quality in the entire state. You will learn what its air quality index number is, why it’s so low, and what that figure means. In addition, we’ll examine how poor air quality affects wildlife in the area and some interesting facts and history about the town itself.

Bar Harbor: The Town with Maine’s Worst Air Quality

The town with Maine’s worst quality is Bar Harbor, a resort town situated on Mount Desert Island along the state’s southeastern coast. Its average air quality index score is 40.8. While this number is still technically within the “Good” quality range on the air quality index, it is on the higher end of the spectrum nearing the “Moderate” range, which can present risks to people especially sensitive to major air pollutants.

Notably, Mount Desert Island is Maine’s largest island out of over 4,000. Despite its lucrative tourism industry, the town’s actual population is fairly small at 5,089 as of the 2020 census. Its population density is around 120 people per square mile. Bar Harbor’s total area is just over 63 square miles. As a coastal town, around 43 square miles of its total area is land, while the other 20 or so is water. 

According to Bar Harbor’s official government website, the Maine Department of Environmental Protection has implemented various air quality programs to continuously monitor air quality in the area based on emissions (and sources of said emissions) and conduct assessments and inspections accordingly.


Bar Harbor, Maine is a coastal tourist town that also unfortunately has the poorest air quality in the entire state.


What Does Bar Harbor’s Air Quality Index Number Mean?

According to AirNow, the air quality index is the U.S. Environmental Protection Agency’s official scale for measuring and accurately reporting air quality across the country. The scale runs from 0 to 500 and has six main categories of severity. Different colors represent these categories, and their value ranges are as follows:

  • Green for good air quality, 0-50
  • Yellow for moderate air quality, 51-100
  • Orange for unhealthy air quality for particularly sensitive groups, 101-150
  • Red for unhealthy air quality in general, 151-200
  • Purple for very unhealthy air quality, 201-300
  • Maroon for hazardous air quality, 301-500

To sum the scale up: the higher the number, the worse the air quality is overall for an area. Notably, AirNow is one of the EPA’s main partners and works closely with them to collect data from towns and cities across the United States on the five major air pollutants:

  • Ground-level ozone
  • Particle pollution, or particulate matter
  • Carbon monoxide
  • Sulfur dioxide
  • Nitrogen dioxide

These five pollutants are the main factors that affect a region’s overall air quality and, by extension, its air quality index number. Many sources of these pollutants exist, with the most impactful being motor vehicle emissions, fuel and natural gas used for heating homes and businesses, by-products from manufacturing products and generating the power necessary to produce them, and fumes released by the production of chemicals. Weather can also affect air quality, as it can affect the ozone and the concentration of pollutants in the air.

A large reason for Bar Harbor’s lower air quality when compared to the rest of the state of Maine is its status as a booming tourist town. More people condensed in a smaller area means higher vehicle emissions. Its lucrative resorts, bars, shops, and casinos, while beneficial for the town’s economy, also produce more of these harmful pollutants that increase its air quality index.

Learn More About Bar Harbor, Maine’s Background and History

Bar Harbor has long been a major tourist hub for Maine and the New England area, but it has a much deeper history than resorts, spas, and retail. It was originally occupied by Wabanaki Indians as well as Passamaquoddy and Penobscot tribes at least as far back as the 1500s. In 1604, however, French explorer Samuel de Champlain crash-landed along the area’s shore, initially believing it to be the nearby island of Egg Rock. 

As Champlain came ashore to repair his boat, he met the local Wabanaki natives. He also named the island Isles des Monts Deserts–French for “island of deserted mountains.” This name would later come to be Mount Desert Island, the island’s current name. The first European village in the Bar Harbor area was established in 1761 by an American soldier and pioneer Abraham Somes. Fittingly, he named the village Somesville. 

But Bar Harbor itself wouldn’t arise until two years later, in 1763. European settlers John Thomas and Israel Higgins didn’t officially incorporate the town until 1796. They named the town Eden after Sir Richard Eden, an English alchemist, translator, and statesman who lived from 1520 to 1576. Notably, Eden’s translations of geographic documents and records largely helped spark interest in overseas exploration in Tudor-era England.

Thanks to Bar Harbor’s rich soil, various industries like lumber, agriculture, and shipbuilding were especially lucrative for the area. This helped bring more settlers and visitors to the area, and eventually, in 1855, Eden’s first hotel opened. Fast-forward just 25 years, and the town had 30 hotels. At this point, it was already establishing its roots as a local tourist destination.

In 1918, the town of Eden was renamed to Bar Harbor. The name comes from the town’s sand and gravel bar that leads to Bar Island, which is mainly covered in forests and is uninhabited, as it is part of Acadia National Park. Today, Bar Harbor boasts more than 100 hotels. Despite its growth being drastically hindered by a devastating wildfire in 1947, its community managed to rebuild, and its local economy is now thriving.

Sunset in Mount Desert Island over Hamilton Pond in Hancock County, Maine, United States, spring Bar Harbor wilderness hiking trail landscape after rain

Mount Desert Island gets its name from French explorer Samuel de Champlain.


How Are Maine’s Wildlife Affected By Poor Air Quality?

Unfortunately, while Bar Harbor’s economy and community are booming and the town has enacted measures to monitor and boost its air quality, it’s still important to address how air pollution affects the area’s local wildlife. Furthermore, because it’s also a coastal town, air pollution has a significant effect on both land- and water-dwelling animals and plants.

One of the most serious effects of poor air quality on Maine’s wildlife is decreased biodiversity. Animals that breathe in lower-quality air have shortened lifespans and higher mortality rates overall. Poor air quality affects entire ecosystems by damaging the habitats in which these native plants and animals live.

Air pollution also significantly affects animals’ food supplies and entire food chains in turn. Studies have shown these air pollutants don’t just pass through these animals’ systems, either. They accumulate in the animals’ body tissues and organs. This further contributes to higher mortality rates. 

What’s more, it gets worse the further up the food chain you go. As animals eat other animals, they eat the pollutants that have built up in their systems. This means apex predators like Maine’s wolves, eagles, and sharks typically have the most pollutants in their bodies. But even plants are affected, too, as key pollutants in the air they breathe significantly stunt their growth.

In short, air pollution doesn’t just make it harder for animals and humans to breathe. Pollutants contaminate the air as well as water supplies. They quite literally build up in animals’ bodies and shorten their lifespans. They even threaten entire native species and allow invasive ones to take over and disrupt ecosystems.

Wolf pack

Maine’s apex predators like wolves are most significantly affected by air pollutants.

©David Dirga/

Where is Bar Harbor Located on a Map?

Bar Harbor, situated on Mount Desert Island along Maine’s Frenchman Bay, acts as a gateway to the scenic mountains and cliffs of Acadia National Park. Visitors can explore the trails and enjoy breathtaking views of the town, the bay, and the Cranberry Islands from the prominent Cadillac Mountain.

Here is Bar Harbor on a map:

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About the Author

Hailey "Lex" Pruett is a nonbinary writer at A-Z Animals primarily covering reptiles and amphibians. They have over five years of professional content writing experience. Additionally, they grew up on a hobby farm and have volunteered at animal shelters to gain further experience in animal care. A longtime resident of Knoxville, Tennessee, Hailey has owned and cared extensively for a wide variety of animals in their lifetime, including cats, dogs, lizards, turtles, frogs and toads, fish, chickens, ducks, horses, llamas, rabbits, goats, and more!

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