CONTRA COSTA COUNTY (KRON) — Air quality is expected to be unhealthy Friday in parts of the Bay Area.

Contra Costa County and Sonoma County have sent statements warning residents.

Smoke can dramatically worsen the air quality, even from fires hundreds of miles away.

Smoke from wildfires contains many air pollutants that are of concern for health.

Exposure to smoky air can make anyone feel unwell, with coughing, scratchy throat, irritated sinuses, shortness of breath, chest pain, headaches, stinging eyes or runny nose.

For some, prolonged exposure to unhealthy air can have serious health effects, including people with cardiovascular or respiratory conditions such as asthma, lung or heart disease, young children, pregnant women and older adults.

Health experts advise everyone to limit their exposure when air quality is poor by staying inside when possible, particularly those in sensitive groups.

Limit strenuous outdoor activity or exercise – anything that makes you take more breaths or breathe deeper.

You may find the following tips helpful:

Call your healthcare provider if your symptoms are severe or worsening.