Huge fires are ravaging large swathes of Canadian forests, sending clouds of smoke towards the United States.

As the haze spreads over the East Coast and the Great Lakes region, health authorities have sounded the alarm about poor air quality.

A online interactive map shows air quality conditions in the United States.

Here are some steps to protect your health in this situation.

STAY IN ENCLOSED SPACES

Small particles in smoke from wildfires can irritate the eyes, nose and throat, and can affect the heart and lungs, making it difficult to breathe. It’s important to limit outdoor activities as much as possible to avoid breathing in these particles, health agencies say. In particular, strenuous activities such as jogging should be avoided, as heavy breathing can increase the amount of smoke inhaled. Bring your pets inside, too: smoke affects pets too.

KEEP INDOOR AIR CLEAN

In enclosed spaces, keep doors, windows and chimneys closed so smoke stays out. If you have a portable air purifier or air conditioning system, use it to keep the air clean, as recommended by the US Environmental Protection Agency (EPA). 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 is as tight as possible to the window. And try to avoid activities that add more particles to the air in your home, such as smoking, lighting candles, or using barbecue grills.

MASK USE

If you go out in smoky conditions, consider wearing a mask, such as N95, to protect your lungs. The mask should be worn over the nose and under the chin, and be as close to the face as possible to avoid smoke.

KNOW YOUR RISKS

Some groups should exercise caution as they face increased risks from smoke from the fires. Children and the elderly are particularly sensitive to smoke. According to the Centers for Disease Control and Prevention, people with health conditions that affect the lungs or heart — such as asthma or chronic obstructive pulmonary disease — are at higher risk for poor air quality, while like pregnant women. Members of these groups should take extra precautions and watch for symptoms such as coughing, breathing problems or fatigue.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical Institute Science and Education Group and the media. The AP is solely responsible for all content.