Massive fires are burning up stretches of Canadian forests and sending plumes of smoke into the U.S.

As a haze stretches over the East Coast and the Great Lakes, health authorities have raised the alarm about poor air quality.

An online, interactive map shows air quality conditions in the U.S.

Here’s how you can protect your health from the smoky haze.

STAY INDOORS

The small particles in wildfire smoke can irritate the eyes, nose and throat, and can affect the heart and lungs, making it harder to breathe. It’s important to limit outdoor activities as much as possible to avoid breathing in these particles, health agencies say. You should especially avoid strenuous activities like going for a run, since heavy breathing will increase the amount of smoke you inhale. And bring pets inside too: Animals are also affected by smoky conditions.

KEEP INSIDE AIR CLEAN

When inside, keep doors, windows and fireplaces shut so that smoke stays out. If you have a portable air purifier or HVAC system, run it to help keep the air clean, the Environmental Protection Agency recommends. Check that your filters are high quality and up to date. Make sure any filters or air conditioners are set to recirculate indoor air to avoid bringing in smoke from outside. If you have a window air conditioner, check that it’s sealed to the window as tightly as possible. And try to avoid activities that would add more particles to the air in your home — like smoking, burning candles or frying meat.