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Hong Kong Observatory vs PM2.5 Open Data Portal

Same instrument, two spec sheets — measured, not claimed.

APIHong Kong ObservatoryHEALTHY60PM2.5 Open Data PortalHEALTHY91
Uptime · 30d
Uptime · 90d100%100%
Uptime · 30d100%100%
P50 · ms1415796
P95 · ms36701352
Authnonenone
CORSyesno
HTTPSyesyes
Card requirednono
Commercial useunclearunclear
Data licenseHKO open data (see terms of use)Unverified
Free tierFree, no keyFree — no API key
Rate limitUnpublishedUnpublished
In directory since2026-07-052026-07-05
operationalpartialdownno data

Hong Kong Observatory vs PM2.5 Open Data Portal: common questions

Which is more reliable, Hong Kong Observatory or PM2.5 Open Data Portal?

Both are neck-and-neck — Hong Kong Observatory and PM2.5 Open Data Portal each measure 100% uptime over 90 days on our probe schedule. Reliability here is verified from our own scheduled checks; use the 30-day bars above to see which has been steadier lately.

Which is faster, Hong Kong Observatory or PM2.5 Open Data Portal?

PM2.5 Open Data Portal has the lower median latency in our checks — Hong Kong Observatory responds in 1415 ms versus PM2.5 Open Data Portal at 796 ms (P50). Tail latency (P95) is in the table above; for most workloads the median is the number that shapes how the API feels.

Do Hong Kong Observatory and PM2.5 Open Data Portal need an API key?

Neither needs a paid key — Hong Kong Observatory is callable with no signup, and PM2.5 Open Data Portal is callable with no signup. Both are quick to prototype with; rate limits still apply.

Can I call Hong Kong Observatory and PM2.5 Open Data Portal from the browser?

Only Hong Kong Observatory is browser-friendly — it returns CORS headers over HTTPS. PM2.5 Open Data Portal needs a server-side call or proxy, so factor that into which one fits a front-end project.

Are Hong Kong Observatory and PM2.5 Open Data Portal free for commercial use?

Hong Kong Observatory has unclear commercial terms, and PM2.5 Open Data Portal has unclear commercial terms. We track service terms and the data license as separate fields — see the Commercial use and Data license rows above, and confirm both before shipping either in a paid product.