Maryland Air Quality Hits Red Due to Canada Wildfires

Cover Photo: File photo of a wildfire

MARYLAND News (6/29/2023) – Unhealthy air quality due to wildfire smoke is expected statewide today, degraded further along the I-95 corridor by Unhealthy for Sensitive Groups (USG) ozone.

Northwest winds Wednesday have pushed smoke from the Great Lakes region into the Mid-Atlantic. Smoke concentrations have been greatest over Western Maryland Wednesday, but have steadily increased statewide. As high pressure moves overhead into Thursday morning, calming winds and surface inversions will act to trap and concentrate smoke at the surface, while at the same time the most concentrated portions of the smoke plume move in from Pennsylvania.

As a result, concentrations of PM2.5 due to smoke on Thursday morning will be notably elevated, with highest hourly concentrations mainly along and north of I-95 toward the Pennsylvania line. Some moderation of concentrations will occur during the day Thursday, but daily average concentrations for most locations are expected in the Unhealthy, red AQI range. Higher daily average AQI for northern areas, slightly cleaner but still expected Unhealthy AQI for southern areas of the state.

At the same time, elevated temperatures nearing 90F in some locations will foster ozone near USG. Smoke is expected to enhance ozone concentrations. Ozone within the USG range is possible near and northeast of DC and likely in and around Baltimore, particularly near northern coastal areas of the Bay.

Late-day Bay Breezes may be laden with high concentrations of ozone, in addition to Unhealthy smoke concentrations. Winds and transport turn southerly Friday. This will offer some reprieve to air quality, though smoke will linger with USG due to smoke possible statewide, with USG ozone possible north of DC and Baltimore. Continued improvement expected Saturday with a return to Moderate, Yellow AQI air quality.

Original article by Maryland Department of the Environment