The risk of a heart attack could be greatly increased by traffic pollution.

According to a big study, sudden braking and exhaust fumes may dramatically raise the risk of heart attacks.

Nitric oxide, a common traffic-related pollutant, has been linked in a study on nearly 18,000 people in Germany to an increased risk of having an attack.

For every 10 g of air pollution added to the daily average, the risk of having a heart attack increased by 1%, and over a three-day period of high pollution, it climbed by 4%.

Researchers found that smokers did not appear to be affected by smog, which is probably because they were already regularly breathing hazardous gases.

It comes after warnings that the UK may experience up to 11,000 annual deaths from heart disease and circulatory conditions as a result of air pollution.

The study, which will be presented this weekend at the European Society of Cardiology’s annual congress in Barcelona, claims that heart attacks decline in hot weather.

Furthermore, a temperature increase of 10°C was associated with a 6% reduction in the frequency of heart attacks.

The study included 17,873 people who had a heart attack between 2008 and 2014.