People with heart conditions may benefit from using indoor air purifiers, suggests a small study from China. 

While the study can't say air purifiers prevent heart attacks or other major medical problems, several risk factors for heart disease improved among young and healthy adults who were exposed to purified air.

"In countries of the world where air pollution is a problem, I think this would be especially important," said Dr.

Sanjay Rajagopalan of the University of Maryland School of Medicine in Baltimore.

The new findings suggest that using an air purifier may lead to a reduction in cardiovascular events, said Rajagopalan, who coauthored an editorial accompanying the new study in the Journal of the American College of Cardiology.

Previous studies found that fine particles in the air are tied to an increased risk of heart-related problems, including heart attack and stroke, the study authors say.

For the new study, Renjie Chen and Ang Zhao of Fudan University in Shanghai and colleagues had 35 healthy college students in Shanghai randomly use real or fake air purifiers in their dorm rooms for 48 hours. Two weeks later, the students spent another two days using whichever type they hadn't used the first time.

China has one of the highest levels of air pollution in the world.

The target air pollution level set by the World Health Organization is 35 micrograms of tiny particles per cubic meter - but daily air pollution in major cities in Asia often exceed 100 to 500 micrograms per cubic meter, Rajagopalan writes in his editorial.

Air purification in the students' rooms reduced air pollution by 57 percent, from about 96 micrograms per cubic meter to about 41 micrograms per cubic meter, the researchers say.

When the students had the real air purifiers in their rooms, they had significant improvements in several measures of inflammation and blood clotting.

They also had some significant decreases in blood pressure and a reduction in a measure of airway inflammation known as exhaled nitrous oxide.

The researchers also found some improvements in lung function and blood vessel constriction, but those findings may have been due to chance.

"You’d have to take the results of these studies as good supportive evidence that these strategies would work," Rajagopalan told Reuters Health.

Dr. Rachel Taliercio, a lung specialist in The Cleveland Clinic's Asthma Center in Ohio, cautioned that the benefit of air purification systems in homes might not be equal for everyone.

"Certainly there is no harm in doing it and there are obviously some benefits," said Taliercio, who was not involved with the new study. "How big those benefits will be is unclear."

Pollution levels in North America, for example, are much lower than in Asia, she said. "So, it’s hard to know if what you see in China is beneficial for North America."

For people who live near high-pollution areas, such as major roadways and coal power plants, air purifiers may be something to look into, Taliercio said.

But, she added, for those living in suburban areas, the devices would be difficult to justify, especially when people consider the cost.

Home air purification systems range in price from hundreds to thousands of dollars. The devices often require replacement filters on a regular basis.

"From the standpoint of what you can do to protect yourself in these polluted environments, investing in home and car air filtration systems will lead to better air quality in the long term," Rajagopalan said.

"One message is at least the awareness that air quality does influence health and chronic diseases, such as heart disease," he said.