Greece · The summary is refreshed every 15 minutes.
October 22
The air is moderate now
Thessaloniki
21°C
Partly cloudy
56AQI
1016hPa
Atmospheric
pressure
77%
Humidity
Thessaloniki, October 21, 2026: daily mean PM2.5 9 µg/m³ (18 sensors), level “Low” — as in the Atmy Data Hub. Now (21:00 local time): 11.8 µg/m³. Open methodology and data in JSON: Methodology and data sources · JSON
Right now in Thessaloniki, PM2.5 averages 11.8 µg/m³ — “moderate” on the US EPA scale (approximate, from hourly readings). Mean of 18 sensors on the Atmy network, readings from 20:16–20:57 local time (17:16–17:57 UTC), summary prepared at 21:00 local time. Median: 10.5 µg/m³; range across sensors: 5.0–32.8 µg/m³.
In Thessaloniki the air is moderate right now (approximate, US EPA scale). From 08:00 to 21:00 local time the city mean PM2.5 rose from 6.6 to 11.8 µg/m³.
Light wind (1 m/s) in the evening or at night, as the air cools, possibly traps particles near the ground (a temperature inversion).
Weather now: partly cloudy, 21°C, wind 1 m/s, humidity 77%. By 08:00 the wind is expected to pick up to 4 m/s, which may clear the air. By 08:00 the temperature will be about 17°C.
Written automatically at 21:00 local time (18:00 UTC) from sensor measurements and the weather forecast. Values are approximate; hypotheses are marked.
4 km/h
Wind, SSW
0 mm
Precipitation today
9 µg/m³ Low
Daily mean PM2.5 on October 21, 2026 (00:00–24:00 UTC): 9 µg/m³ from 18 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.
20%An estimate of weather conditions · not a PM2.5 forecast
23°/15°
Index by time of day
51/100Moderate
Night
Morning
Day
Evening22°/14°
Index by time of day
45/100Moderate
NightMorningDayEvening20°/13°
Index by time of day
55/100Moderate
NightMorningDayEvening19°/15°
Index by time of day
50/100Moderate
NightMorningDayEvening20°/16°
Index by time of day
48/100Moderate
NightMorningDayEvening20°/12°
Index by time of day
36/100Moderate
NightMorningDayEveningForecast of conditions that trap pollution near the surface
21°
Partly cloudy. Feels like 23°C
17°C88%23°C66%20°C84%4km/hWind from the SSW
11km/hWind gusts
Wind force: 1
Light wind is expected over the next few hours.
Greece
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Highest current reading: 32.8 µg/m³ (SC #88511). Lowest: 5.0 µg/m³ (SC #93615). The list shows every sensor, highest first.
Source: atmy.ai monitoring network
Sensors in the summary by network: Sensor.Community — 18 sensors.
Atmy shows the networks’ readings after the Data Hub’s quality check: test devices and sensors that fail it are left out.
47
ThessalonikiGreece
18SerresGreece
4PtolemaidaGreece
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 Thessaloniki: it is refreshed every 15 minutes and links to this page. Paste the code into your site.
Greece · City ranking · All pilot cities
Daily mean PM2.5 on October 21, 2026 (00:00–24:00 UTC): 9 µg/m³ from 18 sensors that passed the quality check — the same value as in the Atmy Data Hub. No. 1 of 1 cities in Greece and No. 151 of 297 worldwide, from the most polluted.
Right now in Thessaloniki, PM2.5 averages 11.8 µg/m³ — “moderate” on the US EPA scale (approximate, from hourly readings). Mean of 18 sensors on the Atmy network, readings from 20:16–20:57 local time (17:16–17:57 UTC), summary prepared at 21:00 local time. Median: 10.5 µg/m³; range across sensors: 5.0–32.8 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: 32.8 µg/m³ (SC #88511). Lowest: 5.0 µg/m³ (SC #93615). 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 365 days with data, the mean daily PM2.5 in Thessaloniki was 8.2 µg/m³ — 1.6 times the WHO annual guideline (5 µg/m³). Over the last 30 days: 4.4 µg/m³. From Atmy's archive of daily city means.
In Atmy's daily archive, the cleanest month of the last year was September 2026: 4.3 µg/m³ on average.
The most polluted month of the last year was December 2025: 13.6 µg/m³ on average.
From November to March the mean daily PM2.5 was 11.4 µg/m³, from June to August 6.3 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
