US & Canada — what's coming

EWG Tap Water Database covers ~50,000 US public water utilities measured at the supply level. EPA AirNow gives ~5,000 real-time air-quality stations. FCC Broadband Data Collection delivers carrier-attested 5G coverage filings. OpenSky has its densest receiver coverage over North America. Canada folds onto US tooling with provincial water-hardness scraping; the Canadian Arctic gets geology-based fallback (granite shield = soft).

Source plan

• Hardness — EWG Tap Water DB + USGS NWIS measured stations
• Air — EPA AirNow real-time + CAMS Global + PurpleAir crowd-sensors
• 5G — OpenCelliD + FCC BDC carrier filings
• Flights — OpenSky + ADS-B Exchange historical archives