Wildfires in eastern Washington State have made the air quality in the Seattle area so poor that it is believed worse than that of Beijing.

The Environmental Protection Agency’s air quality index ranked Seattle at 171, which is considered unhealthy.

At the same time, the index in China, a country plagued by chronic pollution, read 38, which is considered good, according to KIRO-TV.

An ‘unhealthy’ rating from the EPA usually means that people could experience breathing problems or exacerbated symptoms if they are infected with pre-existing lung or heart disease.

Wildfires in eastern Washington State have made the air quality in the Seattle area so poor that it is believed worse than that of Beijing. Smoke is seen above in the air above Seattle on Wednesday

Smoke is seen in the air above the Puget Sound region in the photo above which was taken on Wednesday

The photo above was taken in Lake Washington on Wednesday. The sun's image is distorted by the smoke in the air

The image above shows an elevated point almost 10,000 feet above sea level on Mount Rainier

The smoke is seen in this image showing Mount Rainier from ground level

People in the Puget Sound area are being encouraged to limit the time they spend outdoors and avoid exercising or strenuous activity outside, according to the Seattle Post-Intelligencer.

Residents are also being advised to close windows and doors and to use air conditioning in order to re-circulate fresh air.

Those who are particularly at risk are people afflicted with heart or lung disease, asthma, diabetes, infants, children, adults over 65, pregnant women, and those who have suffered a stroke.

In the 24-hour period between Tuesday and Wednesday morning the air quality was ‘the worst in the nearly two-decade observing record of the Puget Sound Clean Air Agency for any time of the year.’

The image above shows the contrast between the visibility at Olympic National Park on August 3 and that of Wednesday

This photograph was taken in downtown Seattle. There are no clouds visible in the sky due to the heavy smoke created by wildfires in Washington State and British Columbia

The visibility has gotten so bad in most locations that people can only see between three and five miles ahead.

The air over Seattle is being filled with wildfire smoke from blazes in numerous states.

There are currently wildfires burning in 15 Western states as well as the Canadian province of British Columbia.

But the poor air quality in Seattle and the rest of the Pacific Northwest can be blamed on wildfires raging in British Columbia to the north; a number of fires in central and eastern Washington State to the east; and the still-burning California wildfires - the largest in that state’s history.

The smoke from the fires waft into the air and are then taken to wherever the wind blows.

The air quality in the Pacific Northwest is particularly bad, with Portland, Spokane, and Medford all saddled with wildfire smoke.

The National Weather Service has issued an Air Quality Alert exetending from eastern Washington State to northern Idaho.

The alert will remain in effect until 10am on Friday.