(Photo by Joseph Gruber)

If you felt under the weather on Monday, it’s possible D.C. air quality is to blame.

For the first time in six years, the D.C. area experienced “code red” level air quality on July 9, which is air that is unhealthy to breathe for everyone.

The Metropolitan Washington Council of Governments recommends that everyone limit their outdoor activity on such days, as even healthy people can experience negative effects. They advise particularly sensitive people like children, older adults, and people with asthma or heart conditions to be especially careful.

Tuesday is a code orange day, according to the MWCOG, which means that members of sensitive groups still might experience negative effects, but the general public will probably be fine.

The MWCOG recommends the following actions to limit exposure and unhealthy effects on bad air days:

• Turn off lights and electronics when not in use and follow tips from your electric utility about how to use less electricity to cool your home.
• Avoid lawn mowing or use an electric mower.
• Fill your vehicles’ gas tank after sunset.
• Take transit, carpool, or work from home.

Monday’s code red day comes after years of steadily declining air pollution in the Washington area. In 1998, there would have been 15 times as many unhealthy days, according MWCOG.

Just last September, the District was celebrating an entire summer without any code red or purple (very unhealthful) days and eight code orange days.

MWCOG forecasts that Wednesday will be a code yellow day, which may pose a moderate health risk for those who are particularly sensitive to pollution.