BALTIMORE, MD—After a brief respite, Canadian wildfire smoke returned to Maryland on Monday.

Smoky, hazy conditions will likely persist into Tuesday and Wednesday, prompting the Maryland Department of the Environment to issue a Code Orange Air Quality Alert.

A Code Orange Air Quality Alert means that air pollution concentrations within the region may become unhealthy for sensitive groups.

Sensitive groups include children, people suffering from asthma, heart disease or other lung diseases and the elderly.

The effects of air pollution can be minimized by avoiding strenuous activity or exercise outdoors.

Conditions are expected to improve by the end of this week.