The Maryland Department of the Environment issued a Code Red Air Quality Alert for Friday, July 17, covering Prince George’s County, Montgomery County, Howard County, Anne Arundel County, and the Baltimore City metro region, along with Southern Maryland counties including Charles, St. Mary’s, and Calvert. The alert, relayed by the National Weather Service office serving Baltimore and Washington, warns that ground level ozone will reach concentrations considered unhealthy for the general population, not only for children, older adults, and people with asthma or heart and lung conditions.
That distinction matters. Code Orange alerts, which the region has already seen twice this week, apply mainly to sensitive groups. A Code Red alert means anyone spending extended time outdoors is at elevated risk, and few workers spend more consecutive hours outside on a given day than rideshare and delivery drivers, a workforce that includes a significant share of the DMV’s African immigrant community. The region already holds one of the largest Black immigrant populations in the country, and many of those residents work the flexible, often uninsured jobs that keep them behind a wheel or on a bike for most of a shift, regardless of what the sky looks like.
Why ground level ozone is different from smoke or dust
Ozone at ground level is not emitted directly. It forms when volatile organic compounds and nitrogen oxides, both common in vehicle exhaust, gasoline vapors, and industrial emissions, react with sunlight and heat. That reaction peaks on hot, still, sunny afternoons, which is exactly the forecast driving Friday’s alert. Ozone irritates the respiratory tract, can trigger breathing difficulty even in healthy adults, and aggravates existing lung conditions with repeated exposure.
For a driver idling in traffic near an interstate on ramp, waiting outside a restaurant for a delivery order, or making short trips between stops with the windows down, that exposure adds up over an eight or ten hour shift in a way it does not for someone who steps outside only briefly. Unlike office workers, most gig drivers have no employer mandated break policy, no air conditioned break room, and no paid sick leave if symptoms appear.
What drivers and residents can do until the alert lifts
Prince George’s County participates in Clean Air Partners, a regional public private partnership that tracks ozone and fine particle levels and issues daily forecasts. The county advises residents to avoid strenuous outdoor activity, limit vehicle idling, and combine errands into fewer trips, all of which also reduce the emissions that make ozone alerts more frequent. For drivers who cannot simply stay inside, health officials recommend running air conditioning on recirculate rather than open windows, taking breaks in shaded or air conditioned locations between rides or deliveries, and watching for symptoms such as chest tightness, coughing, or unusual shortness of breath.
The alert is set to expire at midnight Friday, though Maryland has issued ozone alerts on back to back days already this week, and forecasters have not ruled out another one heading into the weekend.
FAQ
What does a Code Red Air Quality Alert mean?
It means ground level ozone or fine particle pollution is expected to reach levels considered unhealthy for the entire general population, not just children, older adults, or people with existing respiratory or heart conditions.
Which DMV counties are under alert today?
Prince George’s, Montgomery, Howard, and Anne Arundel counties, the Baltimore City metro area, and Southern Maryland’s Charles, St. Mary’s, and Calvert counties are all covered by Friday’s alert.
Why are rideshare and delivery drivers at higher risk?
Ozone exposure accumulates with time spent outdoors. Drivers who spend most of a shift outside their car or on a bike face longer, more continuous exposure than most other workers, with little ability to take employer mandated breaks.
When does the alert end?
The current alert is in effect until midnight Friday, July 17, though the region has seen ozone alerts on consecutive days this week.