Air quality in Missouri

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

Last update at (local time)


Real-time Missouri
Most polluted city ranking

#cityUS AQI
1 Carthage


2 Union


3 Clayton


4 Stoutsville


5 Saint Ann


6 Saint Joseph


7 Affton


8 Saint Charles


9 Arnold


10 Wentzville


(local time)



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Real-time Missouri
Cleanest city ranking

#cityUS AQI
1 Moberly


2 El Dorado Springs


3 Springfield


4 Harrisonville


5 Webster Groves


6 Kearney


7 Jennings


8 Camdenton


9 Belton


10 Neosho


(local time)


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How to best protect from air pollution?

Reduce your air pollution exposure in Missouri


Is Missouri a polluted state to live in?

Missouri is a state in the Midwestern region of the United States. It shares land borders with 8 other states. The estimated population was just over 6.1 million people in 2020, which made it the 18th most populous state in the US. The capital city is Jefferson City, with other densely populated cities such as St. Louis, Kansas City, Springfield and Columbia.

The Missouri River flows through the centre of the state as far as the Mississippi River which is part of Missouri’s eastern border.

In early 2021. The cleanest city in Missouri was Kearney with a US AQI reading of 16. By contrast, the least clean city was Joplin with a US AQI reading of 77. Two of the other densely populated cities returned a mixed reading with Kansas City coming in at US AQI 60 and St. Louis returning a US AQI reading of 57.

Springfield was the third cleanest city with a US AQI reading of just 38.

Why is the air quality in Missouri measured?

Missouri is the 15th worst state in the nation when it comes to exposing residents to toxic air pollutants from coal-fired power stations. Missouri's electricity generating sector emitted more than 5 million pounds of harmful chemicals in 2010, which accounted for 54 per cent of state pollution and about 2 per cent of toxic pollution from all US power stations.

Recently, air quality standards have been agreed on regarding the 6 most important types of air pollutants, they are ozone (O3), carbon monoxide (CO), particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), lead (Pb) and sulphur dioxide (SO2).

Each state has to decide on the level of acceptability and submit those figures for state approval. Once approved, they form the benchmark against which levels of pollution are judged.

What are the sources of air pollution in Missouri?

Due to the agricultural nature of Missouri, there is a considerable number of livestock rearing farms in rural areas. With these comes the problem of animal waste. Pig manure is usually stored as a liquid in tanks before it is sprayed onto the land as a fertiliser. However, it is getting to the stage where there is so much slurry produced, that the land is unable to absorb such large volumes. The surplus then seeps through the ground and can pollute the underground water table.

The size of the farm does, of course, vary but it is thought that there are some 450,000 animal rearing units in the US. Many are family-run establishments with less than 300 head. But 18,000 units raise thousands of head of stock on an annual basis. Many of these smaller operations are completely unmonitored because their business is looked upon as being “natural” and therefore almost impossible to control.

In 2016, the US produced around 97 million pounds of red meat and poultry which equates to 5.5 per cent of the country’s GDP.

In 2013, it was estimated that the 2.2 billion head of livestock and poultry produced 1.1 billion tons of manure which is the primary source of air pollution in many rural areas.

The main chemical given off by animal waste is methane (CH4). Even though it looks like an extremely useful fuel, it is not an easy chemical to store and capture.

Methane has an impact on climate change which can be 25 times worse than that of carbon dioxide over a period of 100 years. Children are particularly vulnerable when exposed to methane emissions.

The asthma rate of students who attended a school less than half a mile from an intensive rearing site was compared to others who were much further away from such a source. Those near the farm suffered from a 25 per cent asthma rate compared to the control group’s 12 per cent asthma rate.

Can the quality of air in Missouri be improved?

Federal fuel economy standards for cars and light trucks need to be strengthened. These standards are critical to the nation’s efforts to reduce global warming pollution from passenger vehicles.

The support of policies at every level of government to reduce global warming pollution needs to be encouraged, including increasing the use of wind, solar and other clean, sustainable energy and placing state and regional limits on climate pollution.

What can be done to lessen the risk of poor air quality in Missouri?

As part of the quest for cleaner air in the St. Louis area, The Clean Air Partnership is well-known for its daily air quality forecasting. The forecasts take place over the summer months and utilise a colour-coded system designed to keep area local residents informed about ozone pollution levels in their region, and how those levels may affect their health.

On days with high readings on the Air Quality Index, it is suggested that the following precautions are followed:

  • Limit the time spent outdoors, especially if you have asthma or other respiratory issues, or are sensitive to certain pollutants.
  • Avoid prolonged or strenuous outdoor activity.
  • Reschedule outdoor activities for another day, or later in the day when ozone levels are lower.
  • Keep your windows and doors closed at home and in your vehicle to minimise exposure to ground-level ozone.
  • Avoid high-traffic areas, where the concentration of ozone may be especially high.
  • Understand the effects that air pollution can have on your health and be proactive accordingly.
  • Consider the use of an air purifier if one is available.

Is Missouri adopting stricter air pollution standards?

The Missouri Department of Natural Resources has approximately 50 air monitors prominently located throughout the state, including in St. Louis, to monitor concentrations of ozone and other air pollutants.

Ozone (O3) is formed when pollutants emitted by cars, power stations, industrial boilers, refineries, chemical plants and other sources react chemically in the presence of sunlight.

Reducing emissions from cars and other vehicles is among the ways to reduce ozone pollution, as motor vehicle exhaust is a source of nitric oxide, which is oxidised in the atmosphere from nitrogen dioxide. Even simple things such as switching off an idling engine can help make a difference.

Burning fossil fuels such as coal, diesel, gasoline and natural gas creates air pollution in the form of smog, particulates and air toxins. Wildfires, wood stoves, agricultural dust and other sources can also create additional air pollution.

What are the consequences of breathing in polluted air in Missouri?

Smog, or ground-level ozone as it is sometimes called, can cause many respiratory problems, such as coughing, wheezing and throat irritation to asthma, increased risk of infection, and permanent damage to lung tissue, through the scarring of the tissue.

Particulate pollution (PM2.5 and PM10) may cause similar respiratory harm and may also trigger a range of cardiovascular problems, including heart attacks, strokes, congestive heart failure and reduced blood supply to the heart. These problems can result in increased hospital admissions and may even lead to premature deaths.

Particulate pollution has also been shown to trigger premature birth, raise the risk of autism, stunt lung development in children, and increase the risk of them developing asthma at a later age. Recent studies also associate particulate pollution with an increased risk of dementia.

Of course, air pollution does not affect everybody in the same way. The risk of adverse effects mainly depends on your current health status, the pollutant type and concentration, and the length of your exposure to the polluted air.

The groups of people most susceptible to adverse air quality are pregnant women, children under the age of 14 years, senior citizens and the elderly and those whose job dictates that they spend a great deal of time exposed to the outdoor air.

Exposure to high levels of ozone can aggravate respiratory diseases such as emphysema, bronchitis and asthma. The lung tissue can soon become damaged which can be likened to sunburn. A mild form can be repaired by the body’s defence mechanism whereas continuous exposure can lead to permanent damage.

Even short-term exposure can reduce the body’s resistance to infections and can bring about periods of fatigue. Athletes will find that their endurance limits are now considerably lower than from previous sessions.

When is the air pollution at its worst in Missouri?

56 metropolitan areas and four rural counties suffered more than 100 days when smog and/or particulate pollution was “moderate” or higher, in other words, above the level that the EPA has determined presents “little to no risk”. It is estimated that seventy-three million Americans live in those places and are subjected to polluted air far too frequently than is healthy.

Another 241 urban areas and 42 rural counties faced 31 to 100 days which equates to a month or more of smog and/or particulate pollution above the “little to no risk” level. Those places include large metropolitan areas such as Chicago, Miami and Hartford, and it affects smaller communities too. These places are home to 173 million Americans.

Global warming through climate change threatens to exacerbate the nation’s smog and particulate pollution problems because higher temperatures will facilitate the formation of smog and different wind patterns may increase the number of days with stagnant air that prevents dilution of contaminants. Wildfires, which generate particulate pollution and smog precursors that can travel hundreds of miles, are predicted to become more frequent and intense.

Missouri air quality data attribution


Which is the most polluted city in Missouri?

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