New study links PM2.5 air pollution to rheumatoid arthritis flare-ups

Scientists in South Korea wanted to find out why some people with rheumatoid arthritis sometimes feel much worse.

Rheumatoid arthritis is a sickness where the body's own defense system attacks the joints, causing pain and swelling.

The scientists studied more than one thousand patients and paid attention to the air they breathed.

They discovered that when the air is full of tiny pollution specks called PM2.5, the disease becomes more active.

These specks are smaller than red blood cells and can slip from the lungs into the blood.

Once in the blood, they can make the body create harmful chemicals that hurt cells and cause more swelling.

The scientists found that breathing very polluted air for more than two weeks is especially bad.

They recommend that patients with rheumatoid arthritis try to avoid very dirty air.

An editor of the medical journal agrees the finding is important but says more studies are needed to see if it applies to people in other countries.