United States · The summary is refreshed every 15 minutes.
October 22
The air is moderate now
Chicago
16°C
Clear
82AQI
1023hPa
Atmospheric
pressure
78%
Humidity
Chicago, October 21, 2026: daily mean PM2.5 25 µg/m³ (7 sensors), level “Moderate” — as in the Atmy Data Hub. Now (13:00 local time): 25.9 µg/m³. Open methodology and data in JSON: Methodology and data sources · JSON
Right now in Chicago, PM2.5 averages 25.9 µg/m³ — “moderate” on the US EPA scale (approximate, from hourly readings). Mean of 7 sensors on the Atmy network, readings from 12:47–12:47 local time (17:47–17:47 UTC), summary prepared at 13:00 local time. Median: 27.8 µg/m³; range across sensors: 14.7–33.2 µg/m³.
In Chicago the air is moderate right now (approximate, US EPA scale). From 00:00 to 13:00 local time the city mean PM2.5 stayed roughly level: from 28.4 to 25.9 µg/m³. The highest hour was 08:00 with 36.3 µg/m³.
The wind is weak (2 m/s): particles are likely accumulating near the ground.
Weather now: clear, 16°C, wind 2 m/s, humidity 78%. No major change in the wind is expected in the coming hours. By 00:00 the temperature will be about 11°C.
Written automatically at 13:00 local time (18:00 UTC) from sensor measurements and the weather forecast. Values are approximate; hypotheses are marked.
7 km/h
Wind, E
0 mm
Precipitation today
25 µg/m³ Moderate
Daily mean PM2.5 on October 21, 2026 (00:00–24:00 UTC): 25 µg/m³ from 7 sensors that passed the quality check — the same value as in the Atmy Data Hub.
Monthly means of quality-checked sensors, as in the Data Hub trend; the current month is still incomplete, “-” means no data.
8%An estimate of weather conditions · not a PM2.5 forecast
19°/8°
Index by time of day
55/100Moderate
Night
Morning
Day
Evening20°/8°
Index by time of day
55/100Moderate
NightMorningDayEvening21°/9°
Index by time of day
47/100Moderate
NightMorningDayEvening22°/15°
Index by time of day
42/100Moderate
NightMorningDayEvening17°/12°
Index by time of day
34/100Low
NightMorningDayEvening12°/11°
Index by time of day
30/100Low
NightMorningDayEveningForecast of conditions that trap pollution near the surface
16°
Clear. Feels like 16°C
12°C85%19°C65%12°C81%7km/hWind from the E
7km/hWind gusts
Wind force: 2
Gusts up to 16 km/h are expected.
United States
19°C8°C
20°C8°C21°C9°C22°C15°C17°C12°C
12°C11°C20°C11°C15°C9°C13°C7°C13°C8°C
Highest current reading: 33.2 µg/m³ (Wells & Ontario Bus Station). Lowest: 14.7 µg/m³ (Chicago-Logan Square). The list shows every sensor, highest first.
Source: atmy.ai monitoring network
Sensors in the summary by network: AirGradient — 7 sensors.
Atmy shows the networks’ readings after the Data Hub’s quality check: test devices and sensors that fail it are left out.
41
BellevueUnited States
4PortlandUnited States
4RenoUnited States
3Cities with the most sensors
All sensors on the map, by city as the map assigns them; the city’s values count only the sensors that pass the Data Hub’s quality check.
Daily mean PM2.5 of the city sensors, µg/m³
Click a day to see its date and value.
A card with the current PM2.5 in Chicago: it is refreshed every 15 minutes and links to this page. Paste the code into your site.
United States · City ranking · All pilot cities
Daily mean PM2.5 on October 21, 2026 (00:00–24:00 UTC): 25 µg/m³ from 7 sensors that passed the quality check — the same value as in the Atmy Data Hub.
Right now in Chicago, PM2.5 averages 25.9 µg/m³ — “moderate” on the US EPA scale (approximate, from hourly readings). Mean of 7 sensors on the Atmy network, readings from 12:47–12:47 local time (17:47–17:47 UTC), summary prepared at 13:00 local time. Median: 27.8 µg/m³; range across sensors: 14.7–33.2 µg/m³.
The current level is “moderate” (US EPA scale, approximate). Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors. This is the standard guidance of the scale, not medical advice.
Highest current reading: 33.2 µg/m³ (Wells & Ontario Bus Station). Lowest: 14.7 µg/m³ (Chicago-Logan Square). The list shows every sensor, highest first.
From Atmy sensors and connected public networks (citizen, experimental and government monitors), aggregated by Atmy. Values are approximate; see the methodology.
The summary is rebuilt every 15 minutes from the latest reading of each sensor, each no older than one hour.
Over the last 353 days with data, the mean daily PM2.5 in Chicago was 12.9 µg/m³ — 2.6 times the WHO annual guideline (5 µg/m³). Over the last 30 days: 9.7 µg/m³. From Atmy's archive of daily city means.
In Atmy's daily archive, the cleanest month of the last year was May 2026: 7.1 µg/m³ on average.
The most polluted month of the last year was July 2026: 33.3 µg/m³ on average.
From November to March the mean daily PM2.5 was 12.1 µg/m³, from June to August 19.9 µg/m³ (last 365 days).
The daily value is the Data Hub’s: the mean of the city’s sensors that passed the nightly quality check, each with at least 12 valid hours, and only with sensors at four places 500 m apart; days are UTC.
“Now” uses the same sensors and rule: the mean of their latest readings, each at most 60 minutes old, shown only with sensors at four places 500 m apart reporting.
Source: public Atmy monitoring data. Methodology and data sources · Data terms
