BreatheCheck Get alerts

Maryland air quality today

Updated · LIVE · 2 metros tracked

Across the 2 Maryland metros we measure, air is worst right now in Baltimore at AQI 50 (Good) and cleanest in Frederick at AQI 33.

Every Maryland metro we track

#MetroAQIUV nowDominant
1 Baltimoreno page yet 50Good 1.9 PM2.5
2 Frederickno page yet 33Good 3.9 O3

Sun over Maryland today

The strongest UV in Maryland today is 4.3 (Moderate) in Frederick, arriving around 2pm local time. The mildest of the 2 metros we model here peaks at 2.3 in Baltimore.

4.3 Frederick 2pm2.3 Baltimore 2pm

UV is modelled, not measured — unlike the AQI above it, which comes off an instrument. Hour by hour in Baltimore →

What stands behind these Maryland numbers

2 of the 2 metros here report from a named regulatory monitor — Metro Baltimore, Maryland Piedmont. The dominant pollutant across Maryland today is PM2.5 in some metros, O3 in others.

We track 2 metropolitan areas in Maryland, not the whole state, and none of them has its own page yet — a metro page ships only after thirty days of our own history, and that clock is running. There is no state-wide average here on purpose: averaging 2 metros into one figure would invent a value for all the ground between them. How we measure, and what we refuse to estimate →

Neighbouring states

Smoke and inversions do not stop at a state line, so when Maryland looks wrong the answer is often next door.

DelawarePennsylvaniaVirginiaWest Virginia
Worst air in the US right nowHow Maryland compares against every metro we track What the number meansEPA bands, and where “unhealthy for everyone” starts

Updated