As more than 900 wildfires continue to ravage Canada, smoke from the fires is returning to the United States.

Air quality alerts have been issued for the Midwest, Great Lakes, Northeast, and in the South for Tennessee and North Carolina. As the smoke clears, it is a reminder that an air quality index (AQI) above 300 is considered hazardous. You can check air quality conditions at airnow.gov (In English).

CLIMATE CRISIS Wildfires in Canada are not typically as severe at this time of year, but the climate crisis continues to bring high temperatures, little rain, and dry forests. More frequent and intense disasters are devastating communities and disrupting lives due to climate change. In the United States, wildfire seasons are longer, and fires are becoming more frequent and aggressive. Over the past 40 years, the number of acres burned by wildfires has tripled.

WHAT YOU NEED TO DO Follow the advice of local authorities regarding air quality where you live and work. According to the Centers for Disease Control and Prevention According to the CDC, wildfire smoke is a mixture of gases and fine particles that can make anyone sick. People with asthma, chronic obstructive pulmonary disease (COPD), heart disease, pregnant women, children and first responders are particularly at risk.

Inhaling smoke can cause almost immediate effects, such as coughing, difficulty breathing, wheezing, asthma attacks, itchy eyes, sore throat, runny nose and irritated sinuses, headache, fatigue, chest pain and rapid heartbeat.

The most important thing is to try to keep the smoke out.

• Keep windows and doors closed. Choose a room that you can close off from outside air.
• Use fans and air conditioning to stay cool.
• Install an air purifier or portable filter to keep indoor air clean, even if the rest of the building and the outside air are filled with smoke.
• Avoid using candles, gasoline, propane, wood stoves, fireplaces or aerosol sprays, and do not attempt to fry, grill meat, smoke tobacco products or use vacuum cleaners.
• If you have a central air conditioning system, use high-efficiency filters to capture fine smoke particles. If your system has a fresh air intake, set the system to recirculation mode or close the outside air damper.
• If you're using a window air conditioner, make sure the seal between it and the window is as tight as possible and learn how to close the outside air register. For window air conditioners, try running them on fan mode. This won't bring in outside air, but will instead circulate air inside your home.
• If you are in your car, set the air to recirculate.
• Pay attention to any health symptoms if you have asthma, COPD, heart disease or are pregnant. See a doctor if needed.
• Use N95 masks or respirators. Make sure to cover your nose and mouth.