The study's results suggest that pregnant women exposed to air pollution, even at relatively low levels, give birth to smaller babies. They also suggest that living in a greener area could help counteract this effect. (credit:

SOPHIA ANTIPOLIS, France — Air pollution typically contributes to various health problems in the lungs and even in the brain. However, a new study finds common particles in the air may also trigger cardiac arrest.

Sudden cardiac arrest is different from a heart attack, occurring when the muscle stops pumping blood to the body. Researchers says toxic chemicals from traffic and industry show a strong connection to increasing a person’s risk of suffering a cardiac event.

“We studied seven common pollutants and found that as the concentration of each rose, the risk of cardiac arrest increased,” says study author Dr. Francesca R. Gentile of the IRCCS Policlinico San Matteo Foundation in a media release. “The findings suggest that air quality should be incorporated into predictive models to assist health systems in planning service requirements.”

Which pollutants are causing the most harm?

The study in the southern Lombardy region of Italy reveals a “dose-response relationship” between the number of cardiac arrest cases and levels of air pollutants. The findings identify specific pollutants for the first time, shedding fresh light on how air pollution impacts the heart.

These pollutants include tiny particles called PM10s and PM2.5s and gases such as nitrogen dioxide, sulfur dioxide, carbon monoxide, and benzene. Researchers say the tiny particles enter the bloodstream from the lungs, potentially leading to cardiovascular disease, cancer, dementia, and other illnesses.

“The observed relationships between concentrations of individual pollutants and the likelihood of cardiac arrest could be used in future to predict the incidence of this life-threatening condition in specific geographical areas,” Dr. Gentile reports.

The results come from a review of more than 1.5 million people living in urban and rural areas in Pavia, Lodi, Cremona, and Mantua in 2019. Dr. Gentile’s team collected information on the daily incidence of cardiac arrest from the health registry Lombardia CARe, which they compared to Agency for Environmental Protection (ARPA) data on the chemicals. The study finds more cases than normal when concentrations of pollutants are significantly higher.

Heart problems worse in the cold?

The phenomenon applied to all pollutants in the study, after accounting for average daily temperature changes. Researchers included the greenhouse gas ozone, which also contributed to a rise in the risk of cardiac arrest. The risk also rose when temperatures dropped. Studies show that cold weather increases the risk of cardiac arrest.

“We hope that air pollutant monitoring can improve health service efficiency by being factored into ambulance forecasting models and warning systems. In addition to being a threat to the ecosystem, evidence is accumulating that dirty air should be considered a modifiable factor that contributes to cardiovascular disease.” Dr. Gentile says.

Overall, 1,582 out-of-hospital cardiac arrests occurred during the year-long study — an average of 0.3 cases per 100,000 inhabitants a day. In January, the world’s leading heart experts called for authorities to urgently find ways to combat the health implications of air pollution. Dirty air contributed to one in eight (12%) of all global deaths in 2019, with half of these related to cardiovascular disease.

Researchers presented their findings at the virtual meeting of the European Society of Cardiology (ESC).

South West News Service writer Mark Waghorn contributed to this report.

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