Product: AirGradient Open Air (O-1PST / O-1PPT variants)
| Research date: 2026-09-23 | Worker C, air-quality monitors | DESK RESEARCH — no hands-on testing; owner evidence attributed. |
|---|
Overview
Maker: AirGradient. Open-source OUTDOOR monitor — the direct open alternative to PurpleAir for outdoor PM. Variants: O-1PP (PM only), O-1PPT (PM + TVOC/NOx), O-1PST (PM + CO2 + TVOC/NOx). OpenAQ support, unrestricted data ownership, open hardware/firmware.
Social standing
- Independent tester: BreatheSafeAir "AirGradient Open Air Review" (https://breathesafeair.com/airgradient-open-air-review/, page updated ~46 days before 2026-09-23 i.e. ~Aug 2026; snippet-derived) — reviewer personally tested it and compares favorably on price vs PurpleAir/AirVisual: DIY kits ~1/3 the price, assembled ~1/2–2/3. Notes PMS6003 (PurpleAir) dual-laser vs PMS5003T (built-in T/H for compensation) as the honest sensor trade-off.
- Manufacturer comparison vs PurpleAir (https://www-int.airgradient.com/blog/airgradient-vs-purple-air/, snippet-derived; BIAS NOTED, stale ~May 2024): claims similar PM accuracy (same Plantower family); PurpleAir advantages = better map app, SD storage, RGB LED (Flex); Open Air advantages = extra sensors (CO2), open source/data license, lower price.
- lesterchan.net review (snippet-derived): O-1PST kit US$125 / assembled US$225 — conflicts with BreatheSafeAir's $190 assembled; band $190–225, UNVERIFIED current.
- No Facebook owner group or Threads discussion directly observed this pass.
Social validation: Tier 2
Named sources: (1) BreatheSafeAir hands-on review (snippet); (2) lesterchan review (snippet); (3) manufacturer comparison (snippet, bias noted). Weakness: thin direct owner social.
Key specs
| Spec | Detail | Measured vs estimated |
|---|---|---|
| PM1.0 / PM2.5 / PM10 | O-1PPT: 2× PMS5003T; O-1PST: 1× PMS5003T (laser scattering; T/H built in for compensation) | Measured; PM2.5 highest confidence |
| CO2 | O-1PST: SenseAir S8 (NDIR) | Direct NDIR measurement |
| TVOC / NOx | Sensirion SGP41 (O-1PPT/O-1PST) | Index |
| Radon | None | — |
| Temp / humidity | Built into PMS5003T | Direct |
| Display | None | — |
| Connectivity | WiFi; cellular version available | — |
| Power | USB (outdoor power arrangement needed) | — |
| Indoor/outdoor | Outdoor (ASA UV-resistant enclosure) | — |
| Data | Unrestricted ownership; OpenAQ support; open hardware/firmware | — |
Pricing (dated 2026-09-23)
- O-1PST: $125 DIY kit / $190 assembled — BreatheSafeAir (~Aug 2026, snippet-derived). lesterchan lists assembled $225 — conflict noted, current price UNVERIFIED.
- O-1PP: $95 DIY kit; O-1PPT: $170 — BreatheSafeAir (snippet-derived).
What is included / what else is needed
Kit vs assembled choice (same trade-off as ONE: kit cheaper, no warranty/certs). Outdoor mounting + weatherproof power are on the buyer.
Support reality
- Open-source community support; small vendor. No owner support-reputation data observed — UNVERIFIED.
Accuracy (attribution only)
- Manufacturer: PM accuracy "similar" to PurpleAir (same Plantower modules) — bias noted.
- BreatheSafeAir (snippet-derived): treats all listed outdoor monitors as PM-comparable; flags the dual-laser vs compensation trade-off honestly.
- 2026 Changchun study (snippet-derived): AirGradient platform minimal bias vs reference.
Buyer questions
- Which pollutants does it NOT measure? Radon (O-1PP also lacks CO2/TVOC/NOx).
- Is the data trustworthy vs reference? PM2.5 defensible; same overprediction caveats as the Plantower family.
- Subscription/paywall features? API "free for now" (stale manufacturer claim); current terms UNVERIFIED.
Community verdict
The price-performance pick for outdoor PM if you don't need PurpleAir's map network: a fraction of the cost, more sensors on the O-1PST, and open data — traded against a weaker map/app ecosystem and a small vendor.
UNVERIFIED / gaps
- Current assembled price ($190 vs $225); owner failure-mode reports; support reputation; API terms.
Sources (observed 2026-09-23)
- SNIPPET: browser.search → https://breathesafeair.com/airgradient-open-air-review/.
- SNIPPET: browser.search → https://lesterchan.net/blog/2025/10/20/airgradient-one-indoor-monitor-i-9psl-review/.
- SNIPPET: browser.search → https://www-int.airgradient.com/blog/airgradient-vs-purple-air/ (manufacturer, bias noted).
- SNIPPET: browser.search → ResearchGate Changchun 2026 study.
- Private: full recovery log in ../_source-ledger.md (never ships).