What changed & when
Onset through peak
Baseline 2026-09-22 · onset 2026-10-06 · peak 2026-10-08 · latest 2026-10-08. PM2.5 inversion (+208% above 30d baseline).
Hangzhou, China
12 Million Citizens· Asia Metropolitan Baseline1 Noticeable Anomaly: PM2.5 inversion (+208% above 30d baseline)1/p = 1.2 in ~30 daily samples · p=0.01Statistical flag plus WHO guideline exceedance
Gemini AI Synthesis & Plain-Language Summary
In plain English: Hangzhou Fine Particles (PM2.5) is 134.1 versus a 30-day baseline of 43.6 (+208%). PM2.5 is 134.1 µg/m³, very unhealthy on the EPA scale and above the WHO 24-hour guideline of 15 µg/m³. Limit prolonged outdoor exertion; a baseline-normal day can still be unhealthy.
Gemini may only interpret numbers already on this page. Chart annotations below are computed from the dated series (onset, peak, duration, latest vs baseline). Hypotheses are labeled and are not verified causes.
Conversational Telemetry Questions (8 Indicators)
Open-Meteo · CAMS · NASA FIRMS · click a chart for 30/60/90-day investigationWHO 24h guideline: 15 µg/m³. EPA band: Very Unhealthy. 30-day baseline 43.6 µg/m³. Statistical anomaly: yes. CAMS ozone on this page is 0 µg/m³ CAMS O₃ (mass concentration, not station AQI). · Click for dated trend
Baseline 43.6 µg/m³ · q=0.051 · Click for dated trend
High today: 25.3°C. 30-day baseline 24.5°C. · Click for dated trend
Dry spell does not automatically mean drought. Baseline 2.8 mm. · Click for dated trend
Wind helps disperse ground-level pollutants. Click for the humidity trend versus other atmospheric measurements. · Click for dated trend
Sun protection recommended during midday hours.
Standard clear atmospheric line of sight.
Is soil moisture balanced?Root Zone
32%Saturation
Optimal range for local urban vegetation.
See This Change From Space
Travel through satellite observations to discover how this area has changed.
2026-10-08
PM2.5 134.1 µg/m³ · VIIRS true-color · MAIAC/MODIS aerosol
Current · T−1 · T−7 · T−14 · T−30 · NASA GIBS · five snapshots, not a 90-day scrub
Magnitude & spatial extent
Not measured yet
Open the What changed tab to compare baseline and peak pixels. This is a visual aid, not a land-cover map.
Scientific uncertainty
Unusual ≠ unsafe
NASA GIBS true-color is typically about one UTC day behind. Clouds, smoke, and missing tiles can hide the surface; they are not evidence that conditions are typical or safe. Pixel differencing is an unvalidated visual comparison (fixed 15% RGB delta and a brightness cloud heuristic). It is not environmental detection. Onset and peak dates come from the city's modeled Open-Meteo / CAMS series, not from the satellite pixels.
Observed: Hangzhou has an active air statistical flag (PM2.5 inversion (+208% above 30d baseline)). Satellite lookback compares a pre-onset baseline on 2026-09-22 with peak 2026-10-08 and latest 2026-10-08. NASA GIBS layer: VIIRS_SNPP_CorrectedReflectance_TrueColor with MODIS_Terra_Aerosol. Unusual ≠ unsafe — a radar flag is not a health classification, and a visual delta is not a verified land-cover change product.
In the local news · Ground-Truthing via SerpApi
Real-time web corroborationIQAirScience Partner JournalsNature
Hangzhou Air Quality Index (AQI) and China Air Pollution
06/22/2026, 08:50 PM, +0000 UTC
Understudied Health Risks of High-Impact Pollution Weather: The Case for Revising Short-Term PM
06/28/2026, 01:43 PM, +0000 UTC
Acute effects of air pollutants on influenza-like illness in Hangzhou, China
03/26/2025, 07:00 AM, +0000 UTC
Modeled weather: Open-Meteo (ECMWF IFS / GFS blend). Modeled air: Open-Meteo Air Quality (Copernicus CAMS). Observed fire: NASA FIRMS VIIRS 375 m. Observation 2026-10-08T00:00:00Z. Pillar Air Quality Shift.