Even ‘SAFE’ levels of air pollution can trigger heart attacks, and you can be struck within an hour of inhaling dirty air, study warns
- EXCLUSIVE: US Researchers Monitored Nitrogen Dioxide Levels For 15 Years
- As the concentration of the pollutant increases, so does the risk of heart attacks.
Even “safe” levels of air pollution can trigger heart attacks, a study suggests.
The researchers also found that people can be hit in just one hour after breathing dirty air.
Stricter air quality standards are now urgently needed, experts said.
Nitrogen dioxide (NO2) levels, primarily emitted by automobiles, were tracked in nine US cities over 15 years.
The Columbia University scientists then compared this to heart attack hospitalization rates, allowing them to tease out any potential links.
Even “safe” levels of air pollution can trigger heart attacks, a study suggests. The researchers also found that people can be hit in just an hour after breathing dirty air.
Air pollution increases the risk of several conditions, including heart attacks, strokes, and diabetes.
What is nitrogen dioxide?
Nitrogen dioxide (NO2) is a gas produced mainly during the combustion of fossil fuels.
Short-term exposure to NO2 concentrations can cause airway inflammation and increase susceptibility to respiratory infections and allergens.
NO2 can exacerbate symptoms for those who already have lung or heart conditions.
As the concentration of the pollutant increased, so did the risk of heart attacks, just 60 minutes after NO2 levels rose.
The highest risk of heart attack began when NO2 levels remained below current US national standards of 100 parts per billion (ppb).
This threshold means that for every billion units of air, 100 units of NO2 are considered acceptable.
These are in line with the World Health Organization and UK air standards that the hourly concentration should not exceed 200 micrograms of NO2 per cubic meter of air (µg/m³). 100 ppb NO2 equals 191 µg/m³.
UK law currently states that hourly levels of toxic NO2 must not exceed that threshold more than 18 times per year.
However, air quality monitoring tools show that this limit is regularly exceeded in parts of London.
writing in the diary International Environmentthe academics said: “Our findings suggest that current hourly standards may be insufficient to protect cardiovascular health.”
Studies have repeatedly shown that air pollution, especially from traffic, can trigger a heart attack.
This is because inhaling pollutants, which can be so small that they reach deep into the lungs and bloodstream, can restrict blood flow to the heart and force the organ to work harder than normal.
Pictured is a graph showing three measurements of nitrogen dioxide, a pollutant produced primarily by engines and the burning of fossil fuels. Average annual urban background (purple) dropped by nearly a quarter (23%) in 2020
However, it is not clear when the risk of heart problems appears after exposure to pollution and how long it lasts.
The Columbia University team used data on hourly NO2 concentrations for cities in New York state between 2000 and 2015.
The study also involved hospitalization data from 8.9 million people, including 350,000 who suffered a heart attack.
Average NO2 concentrations per hour were around 23.3 ppb.
But every 10 ppb increase appeared to increase the risk of heart attacks by 0.2 percent.
And the risk of a heart attack was highest in the first hour of exposure, when it jumped 0.21 percent.
The risk increased for six hours after the peaks in NO2 rates in all cities and remained elevated for up to 24 hours in some.
Around 100,000 Britons and 800,000 Americans have a heart attack each year.
The WHO has demanded that countries take tougher action as evidence continues to mount about the health risks of small pollutants, which have also been linked to dementia and cancer.
Poor air quality is estimated to cause 7 million deaths each year and remove millions of healthy years of life, according to the UN agency.