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Maryland Department of the Environment

New Air Quality Forecasting System Unveiled

New Air Quality Forecasting System Unveiled

Forecast zones increase from four to 10, ensure more accuracy

BALTIMORE (May 5, 2022) – The Maryland Department of the Environment (MDE) has unveiled a new air quality forecasting system for the state that more than doubles the number of designated areas where forecasts and current conditions are available.

MDE’s Air Monitoring Program of the Air and Radiation Administration posted the new map at
The more localized statewide maps offer more exacting forecasts of ozone and fine-particle air pollution in accordance with the state’s topography.

The 10 forecast regions in the state have year-round particle pollution forecasts and ground level ozone pollution forecasts from April through September. They replace the previous air quality forecasting system, which had only four regional areas — Baltimore metro, Washington D.C. metro, Eastern Shore, and Western Maryland.

The former Baltimore metro region will have a more condensed metro region forecast and two additional regions: Northern Baltimore and Northeast Maryland. The panhandle of the state has been expanded into the Western Maryland and Hagerstown forecast areas. The Eastern Shore has been further refined into upper and lower sections. The former D.C. metro area will now consist of three forecast zones — Suburban DC, Southern Maryland, and Maryland Piedmont.

“These timely improvements deliver more precise and localized forecasting to benefit public health and the environment for all Marylanders,” Environment Secretary Ben Grumbles said.

Here are some more details about the new air quality forecasting zones and the reasons for adding more regions:

Western Maryland/Hagerstown – Garrett and Allegany counties in Western Maryland are higher elevation and more rural and have different air quality from the populated valley around Hagerstown, which has a distinct airshed along Interstate-81.

Maryland Piedmont – This region is a transition from the higher terrain to the west and lower coastal plain to the southeast. It generally does not have heavy influence from urban pollution, making it distinct from other areas.

Northern Baltimore –The higher elevation north of Baltimore is above the coastal plain, making the region less susceptible to poor air quality than at the lower elevations. If air quality is poor, it stems from long-range transport of pollutants from out of state and Baltimore.

Northeast Maryland – Northeastern Maryland is different from the rest of the state because its air quality is related to breezes from the Chesapeake Bay. The region is particularly susceptible to pollution from Baltimore or boats that may be pushed northeastward, impacting only this region.

Metro Baltimore – The Baltimore City area has many pollution sources locally from industry and population density and is impacted by its own pollution when winds are light.

Suburban D.C. – Typical surface flow is from the west or southwest, making this semicircle to the east of D.C. an area susceptible to pollution from the greater D.C. and northern Virginia region.

Upper Eastern Shore/Lower Eastern Shore/Southern Maryland – The upper Eastern Shore of Maryland occasionally finds itself in the plume of the I-95 corridor from Washington D.C. to Baltimore. The Lower Eastern Shore has its own, cleaner airshed. Southern Maryland also is outside the urban pollution plume.

This week is the nationally acclaimed Air Quality Awareness Week and air quality forecasts provided by MDE are available through a variety of sources such as AirNow and Clean Air Partners. Real-time air quality information can be found using these online sources in addition to the Current Air Quality Conditions Map.

Air quality notifications can also be sent to your inbox by signing up for AirNow’s EnviroFlash. The Clean Air Partners and AirNow apps also deliver real-time air quality conditions and forecasts to your smartphone.

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