People across the United States are being advised to remain indoors today as air quality deteriorates, with hazardous particles in the atmosphere linked to serious health issues like cancer, dementia, and stroke.

This alert comes from AirNow, which has evaluated data from numerous air quality monitoring stations across the nation. The organization focuses on tracking Particulate Matter 2.5 (PM2.5), tiny particles emitted from sources such as vehicles, industrial activities, and wood burning.

These PM2.5 particles are small enough to be inhaled deeply into the lungs, potentially causing irritation, coughing, and breathing difficulties.

Reports indicate that individuals with conditions like asthma or heart disease in certain areas of Georgia are being specifically advised to stay indoors due to the heightened pollution levels.

In the northern part of Georgia, both PM2.5 and ozone levels—a gas known to irritate the respiratory system—have escalated to a range of 101 to 150 on the Air Quality Index (AQI). This level necessitates caution for vulnerable groups.

To put this into perspective, the Environmental Protection Agency (EPA) considers an AQI reading of 0 to 50 to be healthy.

But, over the last 24 hours, worsening air quality has led to even healthy people being advised to stay indoors in parts of five other states: Arizona, California, Illinois, Indiana and South Carolina.

These states had AQI levels from 101 to more than 300. Experts warn that an AQI above 150 could cause even healthy people to also suffer from negative health effects.

Currently, AirNow is warning that sensitive individuals in parts of Georgia, such as those with asthma, should remain indoors. Yellow areas indicate that air pollution is moderate, but individuals who are vulnerable may experience mild symptoms, such as coughing

The above map indicates air pollution levels at 3pm yesterday. It shows warnings for all individuals, including those who are healthy, in Bakersfield, California, and a warning in place in Davenport, Illinois

The worst air quality over the last 24 hours was recorded in Bakersfield, California, an industrial hub just north of Los Angeles, which had an AQI of 151 to 200 for eight hours from 1pm to 8pm yesterday.

Bakersfield is considered to be particularly at risk for air pollution because it has two major oil refineries.

In heavily polluted areas, PM2.5 can trigger severe coughing fits, asthma attacks or exacerbate underlying lung conditions.

It is also possible for PM2.5 to enter the bloodstream, where it may trigger inflammation that raises the risk of a stroke or heart attack.

More than 121million Americans have heart disease, estimates suggest, while 35million have an underlying lung condition such as asthma.

Studies suggest that PM2.5 may raise the risk of cancer by triggering damaging mutations in the lungs. Some studies also suggest the inflammation it causes in the body may damage the brain, raising the risk for dementia. 

This inflammation has also previously been linked to a higher risk of suffering from a stroke. 

Scientists say it could raise the risk of plaque, a hard buildup of cholesterol, fat, calcium and other substances on the inner walls of arteries, detaching from blood vessel walls, which could then block a blood vessel and blood from getting to the brain, triggering a stroke.

The air quality warnings may have been triggered by emissions from cars, industry or oil refineries (Stock image of air pollution in Los Angeles)

In some areas, all individuals, even those who were healthy, were advised to stay indoors where possible (stock image)

Currently, AirNow is warning over elevated air pollution levels around Rome, Georgia, which it says are ‘unhealthy for sensitive groups’, suggesting that those who suffer from lung conditions such as asthma should not go outdoors.

It was not clear what was causing the elevated levels in the area, but Rome does have significant manufacturing industries that may be releasing pollutants into the local environment.

In and around Bakersfield, California, yesterday, was ‘hazardous’ air quality, according to AirNow.

This is its highest air pollution category. 

It means that the air is dangerous for everyone to breathe in, even individuals who are healthy, and that it could cause respiratory and heart problems.

AirNow also warned over ‘hazardous’ conditions in Davenport, Illinois, over today and yesterday, warning over the risk from 11am to 1pm yesterday. 

The federal platform also showed elevated levels of air pollution, PM2.5 and ozone in Indianapolis, Indiana, between 8pm and 10pm last night.

It warned that air pollution levels were ‘unhealthy’, the third-highest category that warns anyone who exercises outdoors may experience negative health effects.

People in Payson, Arizona, were also put on notice for PM2.5 air pollution between 2am and 4am today. AirNow marked the air there unhealthy.

AirNow also warned people in parts of northern South Carolina of air pollution that posed a risk for sensitive groups between 7am and 9am today. 

It was unclear what had caused the warnings in these cases, but in previous instances, it has been linked to industrial activity putting pollutants into the environment. 

Dr Vin Gupta, a pulmonologist in Washington’s Seattle area, previously told Daily Mail:  ‘Usually, the worst of the immediate effects [of air pollution] are in somebody with an illness like asthma or emphysema [where tiny air sacs in the lungs are damaged or destroyed]’.

‘Heavily polluted air could cause an exacerbation like chest pain, short breathing, and may require these people to go to the hospital.’