Air quality in Kentucky

Air quality index (AQI) and PM2.5 air pollution in Kentucky

Last update at (local time)


Real-time Kentucky
Most polluted city ranking

#cityUS AQI
1 Paducah


2 Oak Grove


3 Hopkinsville


4 Owensboro


5 Anchorage


6 Corbin


7 Lexington


8 Wilder


9 Louisville


10 Somerset


(local time)



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Real-time Kentucky
Cleanest city ranking

#cityUS AQI
1 Brownsville


2 Highland Heights


3 Burlington


4 Grayson


5 Greenup


6 Pikeville


7 Verona


8 Ashland


9 Hazard


10 Ludlow


(local time)


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Does Kentucky have good air quality?

Kentucky, or more officially known as the Commonwealth of Kentucky, is a state located in the Southeastern portion of the U.S.A, being surrounded by other states such as Virginia, Tennessee, Missouri and Illinois. It also goes by another name of the ‘Bluegrass State’, pertaining to large amounts of grass species known as Kentucky bluegrass that grows prevalently throughout the state, a feature that has aided in supporting the horse breeding industry for many years past.

Kentucky is home to some 4.46 million inhabitants, making it the 26th most populous out of all the American states, and is famous for its horse racing, bourbon, coal, state and national parks, as well as being the birthplace of the world-famous Kentucky Fried Chicken. With its prominence in the production of bourbon comes a huge amount of exportation both domestically and internationally, with this industry only growing in size each year due to increased demand.

There is still the widespread production of coal, although this is not nearly as prevalent as it once was. However, the large amount of exportation coupled with industrial factors and human based activity can all aid in driving the pollution levels up somewhat, which has lead to a number of cities in Kentucky seeing certain months with sudden spikes in pollution, which will be discussed later on.

Despite there being periods of diminished air quality, it still is evident that Kentucky has a respectable level of year round air quality averages, as is shown in the data collected over the course of 2020. To cite some examples, one of its largest cities, Louisville, came in with a yearly PM2.5 reading of 9.1 μg/m³, placing it within the World Health Organizations (WHO's) target goal for the best quality of air at 10 μg/m³ or less. Although this is on the higher end of this group rating, it still stands to reason that it is a good quality of air, coming in within the best air quality bracket possible.

In fact, every city on record in Kentucky came in within the WHO's target rating for the best quality of air, with all 11 cities on the registry as of 2020 having readings ranging from the aforementioned 9.1 μg/m³ (which placed Louisville at 1st place out of all cities in Kentucky, as well as 3059th place worldwide), all the way down to Pikeville with its reading of 6.6 μg/m³. This placed Pikeville in 11th place out of all cities ranked in Kentucky, and 4207th place out of all cities ranked worldwide. This goes to show that despite a few pollutive occurrences happening during certain months, the state maintains a good quality of air through all of its cities for much of the year.

Why is there pollution in Kentucky?

Kentucky has a number of different polluting sources occurring throughout the state, some of them being similar to all other causes of pollution in the United States, and with others being more unique to the state itself. To address the issue of polluting sources that are prevalent throughout the entire country, Kentucky would also have the issue of vehicular emissions, which is a constant problem both in the United States and worldwide.

Cars and other personal vehicles can be seen in massive numbers at any given time inhabiting the road, with their exhaust fumes putting out many chemical pollutants as well as hazardous particulate matter, the variety of which will be discussed in short. Compounding the issue further is the use of larger vehicles such as trucks and lorries, vital components in the importation and exportation industry.

However, these larger vehicles often utilize fossil fuels such as diesel, and due to their great size and weight, as well as their fuel source, can put out much larger amounts of pollution than their smaller roadside counterparts can. Furthermore, the issue of thousands of tons of microscopic rubber particles in the air is an ongoing issue, whereby these particles are generated by the constant wearing down of tire treads, causing huge amounts of this material to be thrown into the atmosphere.

More localized forms of pollution include ones such as coal mining, which can leak many dangerous pollutants into the soil and bodies of water, as well as eventually finding their way into the air as well via the numerous dust clouds that these extraction sites often generate. The use of coal as a power source in factories and power plants is also an issue, with fossil fuels such as coal and natural gas generating more pollution than other sustainable sources would.

Other sources of pollution include ones such as construction sites and demolition areas, both of which can leak large amounts of PM2.5 and PM10 into the air, along with many other dangerous materials such as heavy metals. Forest fires, as well as the burning of firewood within homes typically during the colder winter months, which incidentally is also when power plants are pushed harder in order to provide energy to both homes and businesses for the purposes of heating. In closing, the main sources in Kentucky are vehicular fumes and factory or power plant emissions, with all the other mentioned ones aiding in the visible PM2.5 rises seen periodically throughout the year.

What are some health issues associated with pollution in Kentucky?

Breathing in the various pollutants present in the air throughout Kentucky, one can encounter a myriad of different health effects, ranging from the unpleasant all the way to life-threatening or terminal illnesses. On a more surface level, chemical pollutants and different forms of particulate matter can cause the skin to be affected, as well as causing irritation to the exposed mucous membranes, with the eyes, nose and mouth all be susceptible to breakouts or rashes. The skin is much the same, with instances of acne, atopic dermatitis, psoriasis and eczema all being made possible by overexposure to polluted air, as well as even skin cancer occurring in more extreme cases.

Other health issues would be ones regarding the respiratory system, with higher instances of coughs, chest pain or infections, as well as numerous illnesses that fall under the chronic obstructive respiratory disorder (COPD) bracket. These include ones such as pneumonia and bronchitis, as well as emphysema and aggravated forms of asthma, with young children being particularly vulnerable to developing this last one during their formative years.

Furthermore, due to the insidious nature of fine particulate matter, as well as its extremely small size, it can penetrate deeply into the lung tissue and cause all manner of pulmonary problems, with rapid aging of the lungs as well as scarring of the tissue occurring. These can all lead to decreased lung function (once again under the COPD bracket), as well as making those who are afflicted more vulnerable to the aforementioned respiratory ailments. As for the small size factor, it is actually possible for it to cross over the blood barrier in the lungs via the tiny air sacs, or alveoli, whereby it can enter the bloodstream and cause many more serious issues.

Damage to the blood vessels can occur, as well as even behavioral changes due to alterations to the brain and the nervous system (more common in extreme cases such as overexposure to burnt plastic fumes or for those who live near dangerous industrial areas for extended periods of time), as well as damage also being incurred to the liver and kidneys, and reproductive health is affected. These are a number of the ill health effects that pollution exposure can cause, showing just how important it is for further preventative measures to be taken for those who suffer from overexposure, or belong to high-risk groups.

When is the air quality at its worst in Kentucky?

Observing the data collected over the course of 2020, it can be seen that there were periods of time in which the PM2.5 count was considerably higher than the rest of the year, which as mentioned maintained a very good overall level of air quality. PM2.5 refers to particulate matter that is 2.5 micrometers or less in diameter, being comprised of different materials and on occasion going down to sizes as small as 0.001 microns in diameter or beyond. Due to this extremely small size and varying materials that make up these particles, they are of great danger to human health when respired, and as such make up one of the more prominent components in the calculation of the overall air quality index, or AQI.

Back to the data collected in Kentucky, to use the most polluted city as an example, Louisville saw its highest pollution readings come in at the very end of the year, which is also when the winter months start to descend upon the state. To give some examples, the month of October came in with a fairly respectable reading of 8.6 μg/m³, which then rose up another group rating to 10.8 μg/m³ in November, and then up even further to 12.2 μg/m³ in December. This placed the month in the ‘moderate’ pollution ratings bracket, which requires a PM2.5 reading of 12.1 to 35.4 μg/m³ to be classified as such. This was the most polluted month of the year for Louisville, and was a shared trait amongst nearly all of the cities present in Kentucky, with ten out of the eleven cities registered in the state (on the IQAir website) having their most polluted month occur either in November or December.

What are the main types of pollution found in Kentucky’s air?

Some of the main pollutants in the air in Kentucky would be ones such as black carbon and volatile organic compounds (VOC's). Some examples of VOC's include chemicals such as benzene, toluene, xylene, methylene chloride and formaldehyde, all of which are extremely dangerous and easy to respire even in freezing conditions, due to their volatile nature keeping them in a gaseous state at lower temperatures.

Other prominent ones would be nitrogen dioxide (NO2) and sulfur dioxide (SO2), as well as carbon monoxide (CO) and ozone (O3), all of which see their release either from car exhaust fumes, or as a result of being formed in the atmosphere from a reaction between various chemicals, such as the various compounds of nitrogen (NOx) being subject to large amounts of solar radiation from direct sunlight, forming ozone. Silica or gravel dust would also be present, along with polycyclic aromatic hydrocarbons, and even toxic metals such as lead, mercury and cadmium.

Kentucky air quality data attribution


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