# Baltimore, MD Air Quality Index (AQI) Today > Source: https://breathecheck.com/air-quality/us/maryland/baltimore/ > Live AQI for Baltimore, MD with a plain verdict — go, short and unloaded, or don't go — plus the monitor behind it and our own hourly record. # Baltimore, MD Air Quality Index (AQI) Today Readings collected automatically every hour; text written and checked by BreatheCheck Editorial . How this page is made → Right now: Baltimore is at 37 , good . ## Is the air safe to breathe in Baltimore today? In Baltimore, BreatheCheck reads 37 as Go . The cutoffs: go below 101 , keep it short and easy from 101 to 150 , move it indoors above 150 . These are our own thresholds, drawn on the EPA bands — EPA itself classifies 101–150 as Unhealthy for Sensitive Groups and does not tell you how long to stay out. Go AQI 0–100 Normal outdoor plans. No change needed. Short & unloaded AQI 101–150 A 20-minute dog walk, not a 2.5-hour run. Keep it brief and easy. Don’t go AQI 151+ Move it indoors. Above 200 that becomes everyone, not just sensitive groups. Above 200 this stops being a personal call: everyone indoors. Duration and intensity are two separate dials | Under 20 min | 20–60 min | Over an hour | | Easy | Go | Go | Go | | Moderate | Go | Go | Go | | Hard | Go | Go | Go | Go Every combination lands the same way at this reading — a hard hour is no different from an easy twenty minutes. The two dials separate above 80 . Where people actually draw the line **All the thresholds people reported, and who reported them** - 60 Asthmatic runner one runner’s own 156-run log - 75–100 Daycare / school parents and staff in one r/toddlers thread, Aug 2025 — not a published rule - 100 Parent community-reported, escalating at 150 and 200 - 110 Runner community-reported EPA classifies 101–150 as Unhealthy for Sensitive Groups. That is an attributed classification, not a verdict on your lungs specifically. If you’re staying in, filter the room you’re actually in A portable HEPA unit or a Corsi-Rosenthal box — one builder put theirs at about $130 for a 12×14 bedroom. We don’t default to a MERV-13 swap in whole-house HVAC: it can restrict airflow, and the safe version needs a static-pressure check first. Dominant pollutant O3 UV index 0.4 low · modelled UV hour by hour in Baltimore → Days above AQI 100 0 of 30 days we have recorded The record, day by day → ### A coal pier four blocks from the houses Baltimore’s most measurable local source sits at the far southern end of the city. Curtis Bay is a residential grid about four blocks wide and fifteen long, built on sloping heights and wrapped on its northeast, east and southeast sides by a dredged deep-water channel and the industry along it: a coal export terminal on the water, the Coast Guard Yard, rail lines and the truck traffic feeding them. Monitoring run by residents with Johns Hopkins researchers documented coal dust leaving the terminal’s fence line at intervals of roughly an hour and a half, and coal particles turning up as much as three-quarters of a mile into the streets behind it. That is a scale nothing metro-wide can represent. Two Baltimore neighborhoods a few miles apart are not breathing the same air on the same afternoon, and one monitor speaks for both of them. The rest of the city’s load is what a working port produces: terminal equipment and the ships waiting on it, I-95 and I-895 diving under the harbor in tunnels, the Beltway around the outside. What sets Curtis Bay apart is not that it has an industrial neighbor. It is the distance involved, which is measured in city blocks. ## Where this number sits Of the 121 US metros reporting to us right now, Baltimore is number 70 and the highest of the 2 we track in Maryland. The pollutant driving it today is O3 . Nearby metros we also measure, and what they read at the same hour: - Washington, DC — 35 miles away, AQI 42 - Frederick, MD — 44 miles away, AQI 33 - Dover, DE — 59 miles away, AQI 37 - Wilmington, DE — 65 miles away, AQI 31 Why a metro a short drive away reads differently → Where this reading comes from AirNow’s Metro Baltimore reporting area, about 7.2 miles from the metro centre. ## What has air quality in Baltimore actually been? Daily maximum, our own readings. 30 days since 2026-08-16; nothing back-filled. Why we keep our own → 0 of the 30 days we have recorded so far went above AQI 100. | Date | Daily max AQI | EPA band | Hours read | | 2026-09-14 | 48 | Good | 22 | | 2026-09-13 | 41 | Good | 23 | | 2026-09-12 | 49 | Good | 23 | | 2026-09-11 | 44 | Good | 23 | | 2026-09-10 | 56 | Moderate | 23 | | 2026-09-09 | 74 | Moderate | 23 | | 2026-09-08 | 52 | Moderate | 23 | | 2026-09-07 | 46 | Good | 23 | | 2026-09-06 | 51 | Moderate | 23 | | 2026-09-05 | 52 | Moderate | 23 | | 2026-09-04 | 54 | Moderate | 23 | | 2026-09-03 | 52 | Moderate | 24 | | 2026-09-02 | 59 | Moderate | 23 | | 2026-09-01 | 68 | Moderate | 23 | | 2026-08-31 | 65 | Moderate | 23 | | 2026-08-30 | 51 | Moderate | 23 | | 2026-08-29 | 41 | Good | 12 — partial day | | 2026-08-28 | 44 | Good | 22 | | 2026-08-27 | 57 | Moderate | 23 | | 2026-08-26 | 56 | Moderate | 23 | | 2026-08-25 | 57 | Moderate | 23 | | 2026-08-24 | 57 | Moderate | 24 | | 2026-08-23 | 42 | Good | 23 | | 2026-08-22 | 53 | Moderate | 23 | | 2026-08-21 | 53 | Moderate | 23 | | 2026-08-20 | 60 | Moderate | 23 | | 2026-08-19 | 54 | Moderate | 23 | | 2026-08-18 | 52 | Moderate | 23 | | 2026-08-17 | 53 | Moderate | 26 | | 2026-08-16 | 52 | Moderate | 7 — partial day | ## Questions about Baltimore **What is the air quality in Baltimore right now?** AQI 37 — Good. That is number 70 of the 121 US metros reporting to us at this hour. **Which monitor does this number come from?** Metro Baltimore, about 7.2 miles from the metro centre. One instrument reports for the whole metro, so the side farthest from it is the least well described. **How does Baltimore compare with metros nearby?** At this hour: Washington 42, Frederick 33, Dover 37, Wilmington 31. Readings that close together suggest one airshed rather than local sources. **Does this include pollen?** No. The AQI covers PM2.5 , PM10 , ozone, NO₂, SO₂ and CO. A high-pollen day can read clean here and still put someone in bed. What the number means, band by band → · UV in Baltimore → · Why apps disagree → ## Put this number in context On this page Alert me when Baltimore turns One email when it crosses your threshold. Updated 14 Sep 2026, 22:12 UTC