As fires rage in California, more information is coming out air pollution's risk for serious health problems.

High levels of fine particles (called PM2.5) in smoke, burning coal, and road traffic have been found to increase the risk for dementia. High daily levels are also associated with chronic bronchitis, reduced lung function, and lung cancer — and they worsen chronic conditions such as heart disease and asthma.

In the short-term, those tiny particles can trigger eye, nose, throat, and lung irritation, coughing, shortness of breath. asthma attacks, and other respiratory symptoms.

Now research shows that exposure to those particles increases the risk for autoimmune ulcerative colitis.

Writing in Scientific Reports, scientists suggest that the risk comes from pollution-triggered epigenetic changes (genes that get turned on or off), immune system damage, or chronic inflammation.

The study also shows that exposure to larger particles called PM10 is associated with developing autoimmune psoriasis, and that nitrogen oxide pollution from burning fossil fuels raises the risk of rheumatoid arthritis, lupus, and Sjogren's.

Your best protection: When indoors, use a free-standing HEPA air filter or consider installing a high-efficiency filter (MERV 13 rating or higher) — if your ventilation system can handle it. Set central air conditioning and heating systems to "on," not to "auto," so air is constantly filtered.

In addition, you should wear an N95 or KN95 mask when outdoors if air quality in your area is an issue.