BOSTON — Residents in various areas of eastern Massachusetts were greeted with the unpleasant odor of smoke on Monday as firefighters battled multiple brush fires.

According to the National Weather Service, the smoke hung low to the ground in the morning due to a phenomenon called a “surface inversion,” which results in cooler air being trapped beneath warmer air. Fortunately, by the afternoon, the smoke had mostly dissipated.

In the last 24 hours, the state Department of Fire Services reported a total of 18 active brush fires across Massachusetts. Tragically, an outdoor fire at an encampment in Millbury on Saturday resulted in a woman’s death.

Current weather conditions throughout the state increase the likelihood of brush fires in all communities. State fire officials have highlighted that dry leaves, dead vegetation, and other combustible materials are particularly susceptible to ignition.

“While the dry, sunny, and breezy weather offers great opportunities for outdoor activities, it also means that any fire started outdoors can escalate quickly and become very challenging to control,” stated State Fire Marshal Jon Davine. “We are witnessing preventable fires expanding into dangerous situations, necessitating significant resources both locally and from surrounding areas.”

Fire officials have issued a reminder that open burning is prohibited across the state until January and is banned year-round in many municipalities. They have also advised residents to refrain from outdoor cooking and heating, and to exercise caution when using power equipment such as lawnmowers and leaf blowers, as their engines can generate enough heat to ignite dry leaves and grass.