David Chen

"In the environmental health space, ambiguity harms people. When a family asks whether a neighborhood is safe for an asthmatic child, or when someone is choosing an air purifier during a wildfire smoke event, marketing claims and single-day AQI snapshots are insufficient. They need verifiable, multi-year empirical measurements."

At Clean Air Data, David oversees the data aggregation pipeline connecting federal monitoring records (EPA AirNow and AQS) with independent consumer hardware benchmarks. All recommendations on this platform adhere to strict scientific boundaries:

• No Modeled Guesses on Ground Monitors: We strictly delineate between ground-truth Federal Reference Method (FRM) stations and proxy monitor estimations. Monitor distances are explicitly disclosed on every city report.
• Zero Pay-to-Play Filtration Ratings: Purifier assessments must pass rigorous physics checks: True HEPA (capturing 99.97% of particles down to 0.3 microns) and true granular activated carbon bed weight rather than paper-thin carbon sheets.
• 2024 EPA NAAQS Alignment: All historical rankings benchmark against the EPA's revised 9.0 μg/m³ annual PM2.5 threshold and WHO's 5.0 μg/m³ global benchmark.