Qualité de l’air à Anchorage

What is the air quality like in Anchorage?

Anchorage, otherwise known as the Municipality of Anchorage, is a city located in Alaska, on the western coast of the United States. In late June of 2021, Anchorage was seen with a US AQI reading of just 1, placing it into the absolute lowest end of the 'good' ratings bracket, which requires a US AQI reading of anywhere between 0 to 50 to be classified as such.

This represents the best level of air quality, and is color coded as green for ease of navigation and reference on the air quality maps, graphs and forecasts found on this page as well as throughout the IQAir website. With a reading of 1, Anchorage would be significantly free from clouds of smoke, haze and other air contaminants that are found in more busy or polluted cities.

These readings are subject to change however, with other US AQI readings taken over the course of June coming in with figures of 17 and 21. These both still fell within the 'good' ratings bracket, indicating that Anchorage has a very good level of air quality, with past records also showing every month of the year coming in within the World Health Organization's (WHO's) target goal of 10 μg/m³ or less, for the best quality of air.

Alaska as a whole has some pollutive issues, with organizations such as the American Lung Association citing that as of 2019, Alaska has shown some of the worst air quality throughout the US, with pockets of pollution appearing across certain cities for a number of reasons. These will be discussed later in the article in regards to causes of pollution in Anchorage and Alaska as a whole.

Meteorological events such as strong winds and lack of rain can also cause clouds of smoke and fine particles (PM2.5) arising from distant polluting events (such as wildfires) to float many miles, settling over cities and causing their pollution reading to go up significantly.

It is during events such as these that staying up to date with pollution levels becomes all the more important, with US AQI readings and PM2.5 levels being shown on the air quality map present on this page, as well as via the AirVisual app. Forecasts are updated hourly and can be subject to change, and as such, frequent checking of pollution levels can help individuals to keep their exposure to a minimum, particularly if they belong to a vulnerable demographic.

Regarding the US AQI reading, US AQI itself is a number aggregated from the volume of main pollutants found in the air throughout Anchorage. These include ones such as nitrogen dioxide (NO₂), ozone (O₃) and sulfur dioxide (SO₂), along with the two forms of particle pollution, PM2.5 and PM10.

With such low readings present in Anchorage, the subsequent volumes of these pollutants would also be low, indicating a very safe level of air quality to breathe.

In 2020, Anchorage was seen with a PM2.5 reading of 5.1 μg/m³ as its yearly average. This placed it into the WHO's target goal of 10 μg/m³ or less, as well as placing it in 4542^nd place out of all cities ranked worldwide, as of 2020. This indicates a very good level of air quality, placing it into the upper echelons of cleanest cities worldwide.

As such Anchorage would be a city in which those with poor heath or respiratory issues would be able to reside without being subject to any of the ill effects that pollution can bring. However, as mentioned, pollution levels can change suddenly and should always be monitored.

What are some causes of air pollution in Anchorage?

Whilst Anchorage showed a very good level of air quality, both in more recent times mid-way through 2021, as well as 2020 also having a good level of air quality present, there would still remain sources of air pollution. With any level of human or industrial activity comes polluting elements, due to processes such as combustion taking place in many factories, power plants and even car engines, all of which give out their own forms of chemical pollutants and fine particles.

As mentioned, vehicles would be a contributing factor to rising air pollution levels in Anchorage and throughout the whole of Alaska. A variety of these vehicles include ones such as cars, snowrunners and motorbikes, along with heavier freight vehicles used for mass transport and industry, which include trucks, lorries and buses.

Many vehicles throughout certain areas in Alaska, particularly rural ones, still utilize diesel as a main fuel source, and as such can give out the large amount of pollutants that come from the combustion of the fossil fuel. Furthermore, vehicles can leak oil vapors, particularly when they are aged and not in perfect condition, as well as giving out many tons of rubber particles from the wear and tear of tire treads.

These rubber particles can enter into the atmosphere and cause health issues when inhaled, as well as gathering on the ground and in bodies of water, causing damage to the environment and various ecosystems.

Other causes of pollution include smoke given off from wood burners, which once again come mainly from aged or lower quality units, or ones that do not meet a certain standard when it comes to the complete combustion of materials such as charcoal and firewood.

The incomplete, or poor combustion of these materials can lead to larger amounts of certain pollutants being released, which will be discussed in the following question. With extreme levels of cold present in Alaskan cities, many inhabitants would rely on such wood burners to provide heating, with usage rising during the colder months of the year.

Smoke from wildfires can also cause air pollution levels to rise, and although they were not present in or around Anchorage over the course of 2020 and are not currently presenting a threat in mid-2021, the spontaneity of their appearance can cause large jumps in the pollution levels along with fine particles, or PM2.5.

PM2.5 refers to particulate matter that is 2.5 micrometers or less in diameter, making it 30 times smaller than the width of a human hair. Due to this size factor (as well as being able to go down to ultrafine sizes many microns smaller), it can penetrate deep into the lungs upon inhalation, causing a whole host of health issues to appear. Furthermore, it can cross into the bloodstream due to its minute size, making it one of the most dangerous pollutants found in the air, both in Anchorage and throughout the world.

Other sources that contribute to air pollution levels would be ones such as power plants, factories and industrial sites, many of which would use fossil fuels such as coal, natural gas and diesel to provide their energy. A surge in demand for electricity can also appear in the colder months, for the heating of both homes and businesses, which can further compound the polluting effect brought on from increased burning of organic materials.

These sources are not widespread throughout Anchorage, and may cause elevations of pollution to be concentrated around their immediate vicinity, with large amounts of sprawling, empty land in Alaska putting suitable distance between polluting industrial sites and human populations.

The issue of thermal inversion also has its part to play in pollution buildups throughout Alaska. With colder air having a higher density to it, it can remain trapped at ground level whilst the air above remains warmer, perpetuating the whole cycle and causing pollutants to remain stuck at ground level, unable to rise into the upper atmosphere and disperse safely away from where they could affect people. During the winter months, the distinct lack of sunshine causes the ground to become the coldest area, suppressing any vertical mixing of air.

What pollutants can be found in the air in Anchorage?

Whilst the various pollutants that go into making up the US AQI reading have already been touched upon, there remain a large amount of other pollutants in the air (once again concentrated in certain areas more prevalently) that can also have a highly damaging effect on both human health and the environment.

These would be ones such as black carbon and volatile organic compounds (VOCs). Black carbon is the main component of soot, and can be released from a wide variety of sources. The aforementioned wood burning stoves can release both of these pollutants, contributing to both indoor and outdoor pollution levels.

Both black carbon and VOCs can be formed from the incomplete combustion of fossil fuels and organic material, and as such can find their release from forest fires, woodburning stoves, factories and vehicles. Black carbon is a highly dangerous form of PM2.5, and has known carcinogenic properties when inhaled. Furthermore, it has a heating effect on the environment, due to its property of absorbing solar radiation and releasing it directly as heat, giving it the ability to cause environmental damage as well as being injurious to human health.

VOCs are named as such due to their ability to maintain a gaseous state even at lower temperatures, thus being easier to breathe in environments that have extremes of cold.

Some examples of VOCs include ones such as benzene, toluene, xylene, styrene, methylene chloride and formaldehyde, all of which have a whole host of negative effects on human health. They are also one of the main sources of indoor pollution, and can come from a number of innocuous sources such as certain glues, varnished woods and surfaces, paints, along with cosmetic products and other similar items such as scented candles and indoor air fresheners.

Other pollutants that may be found in certain areas, particularly near industrial sites include ones such as heavy metals like mercury, lead and cadmium. Polycyclic aromatic hydrocarbons, dioxins and furans may also be found, once again depending on the industrial or anthropogenic activity taking place within a certain area. However, the main pollutants remain as ones that come from the combustion of charcoal and firewood, along with smoke from vehicles and power plants.

What are some health effects caused by breathing polluted air in Anchorage?

Health effects that would be picked up by people exposed to pollution in Anchorage would be few and far between, due to the extremely clean levels of air quality. However, for informational purposes, a number will be named as any level of pollution exposure has the chance to cause adverse health effects, particularly in areas where pollution levels are more concentrated.

They would include ones such as dry coughs, inflammation of the lungs, asthma, along with a variety of other respiratory conditions that fall under the chronic obstructive pulmonary disease (COPD) bracket. They include ailments such as bronchitis, pneumonia and emphysema.

Exposure to larger amounts of fine particles, particularly when taken over long periods of time, carry with them conditions such as ischemic heart disease, strokes, arrythmias, heart attacks and even death, showing the severity of pollution exposure and its effects on human health.

When does Anchorage have the worst level of air quality?

Observing the air quality data taken over the course of 2020, it can be seen that every month of the year fell within the WHO's target goal of 10 μg/m³ or less. However, some of the months on record had slightly higher readings, with January, March and November having the highest readings of PM2.5, relatively speaking.

Their readings were 8 μg/m³, 6.2 μg/m³ and 7.5 μg/m³. These are still optimal by international standards, but Januaries reading of 8 μg/m³ put it over double the amount of some of the cleaner months on record, with June of 2020 coming in with a very clean reading of 2.9 μg/m³.

Has the air quality shown improvements in Anchorage?

Yearly averages of air pollution taken in Anchorage show that a steady improvement has been made. Although the improvement was not drastic, and prior year's readings would still place Anchorage in a respectable position, any level of improvement is a positive step in the right direction.

From 2017 through to 2020, the yearly readings were 6.5 μg/m³, 5.9 μg/m³, 8.1 μg/m³ and then 5.1 μg/m³ in 2020. This shows a marked improvement over the course of 2019 to 2020, and with further years readings Anchorage may show even further improvements and an even better ranking on the global circuit.