# St. Paul, MN Air Quality Index (AQI) Today > Source: https://breathecheck.com/air-quality/us/minnesota/st-paul/ > Live AQI for St. Paul, MN with a plain verdict — go, short and unloaded, or don't go — plus the monitor behind it and our own hourly record. # St. Paul, MN Air Quality Index (AQI) Today Readings collected automatically every hour; text written and checked by BreatheCheck Editorial . How this page is made → Right now: St. Paul is at 23 , good . ## Is the air safe to breathe in St. Paul today? In St. Paul, BreatheCheck reads 23 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 PM2.5 UV index 0.6 low · modelled UV hour by hour in St. Paul → Days above AQI 100 3 of 30 days we have recorded The record, day by day → ### Cold air in the trench, smoke overhead Two conditions produce this city’s bad readings and they have nothing to do with each other. The first is local and small. The Mississippi runs through St. Paul in a trench between steep bluffs, and on a still, clear, subzero night cold air drains off the high ground into it while a surface inversion caps whatever has collected there, holding vehicle exhaust and residential wood smoke near the ground until the sun climbs far enough to break the layer. The neighborhoods down on the flat and the ones on top of the bluff line are not breathing the same air on those mornings. Flint Hills Resources’ Pine Bend refinery, the largest in Minnesota, sits down the same valley at Rosemount and Inver Grove Heights, which a southeasterly puts upwind. The second condition is continental. Minnesota shares a border with Manitoba and Ontario and lies in the usual downwind path of Saskatchewan’s fires as well, and since 2023 the state’s air quality alert record has been dominated by smoke arriving from boreal forest outside the country. That year ran alerts over more days than any year before it. Nothing about the two overlaps. An inversion morning is worst before dawn, usually gone by afternoon, and worse in the trench than a mile away on top of the bluff. Smoke keeps no hours, covers the whole state at once, and can hold for a week. ## Where this number sits Of the 121 US metros reporting to us right now, St. Paul is number 113 and number 3 of the 3 we track in Minnesota. The pollutant driving it today is PM2.5 . Nearby metros we also measure, and what they read at the same hour: - Minneapolis, MN — 9 miles away, AQI 23 - Rochester, MN — 71 miles away, AQI 24 - Sioux Falls, SD — 204 miles away, AQI 22 - Cedar Rapids, IA — 215 miles away, AQI 19 Why a metro a short drive away reads differently → Where this reading comes from AirNow’s Twin Cities reporting area, about 4.8 miles from the metro centre. ## What has air quality in St. Paul actually been? Daily maximum, our own readings. 30 days since 2026-08-16; nothing back-filled. Why we keep our own → 3 of the 30 days we have recorded so far went above AQI 100. | Date | Daily max AQI | EPA band | Hours read | | 2026-09-14 | 58 | Moderate | 22 | | 2026-09-13 | 34 | Good | 23 | | 2026-09-12 | 69 | Moderate | 23 | | 2026-09-11 | 113 | Unhealthy for Sensitive Groups | 23 | | 2026-09-10 | 51 | Moderate | 23 | | 2026-09-09 | 54 | Moderate | 22 | | 2026-09-08 | 57 | Moderate | 23 | | 2026-09-07 | 52 | Moderate | 23 | | 2026-09-06 | 57 | Moderate | 23 | | 2026-09-05 | 48 | Good | 23 | | 2026-09-04 | 62 | Moderate | 23 | | 2026-09-03 | 101 | Unhealthy for Sensitive Groups | 24 | | 2026-09-02 | 87 | Moderate | 23 | | 2026-09-01 | 52 | Moderate | 23 | | 2026-08-31 | 61 | Moderate | 23 | | 2026-08-30 | 60 | Moderate | 23 | | 2026-08-29 | 149 | Unhealthy for Sensitive Groups | 23 | | 2026-08-28 | 63 | Moderate | 22 | | 2026-08-27 | 82 | Moderate | 23 | | 2026-08-26 | 64 | Moderate | 23 | | 2026-08-25 | 67 | Moderate | 23 | | 2026-08-24 | 65 | Moderate | 24 | | 2026-08-23 | 96 | Moderate | 23 | | 2026-08-22 | 95 | Moderate | 23 | | 2026-08-21 | 60 | Moderate | 23 | | 2026-08-20 | 69 | Moderate | 23 | | 2026-08-19 | 70 | Moderate | 23 | | 2026-08-18 | 56 | Moderate | 23 | | 2026-08-17 | 51 | Moderate | 26 | | 2026-08-16 | 31 | Good | 6 — partial day | ## Questions about St. Paul **What is the air quality in St. Paul right now?** AQI 23 — Good. That is number 113 of the 121 US metros reporting to us at this hour. **Which monitor does this number come from?** Twin Cities, about 4.8 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 St. Paul compare with metros nearby?** At this hour: Minneapolis 23, Rochester 24, Sioux Falls 22, Cedar Rapids 19. 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 St. Paul → · Why apps disagree → ## Put this number in context On this page Alert me when St. Paul turns One email when it crosses your threshold. Updated 14 Sep 2026, 22:12 UTC