PM2.5 — is expected to push the Air Quality Index over 100, reaching levels unhealthy for sensitive groups, including children, older adults, and people with heart or lung conditions.

Forecasters say weak winds have left Canadian wildfire smoke to linger over the U.S. Stronger winds are expected to bring relief later in the week.

An air quality alert went into effect for the metropolitan area went out Monday at midnight and continues until midnight Tuesday.