Air Purifier vs Humidifier: Orthogonal Machines, the CADR and Humidity Arithmetic, and Why One Can Sabotage the Other
An air purifier and a humidifier don't compete — they're orthogonal. The purifier removes particles from air (its performance is rated ...
Air Quality Mold Testing: CDC’s Inconvenient Advice (If You See It, Don’t Test It), the $10 Kit Problem, and the Three Cases Where Testing Earns Its Cost
The Centers for Disease Control's position inverts what most mold content implies: if you can see mold or smell it, skip testing and go...
Air Quality Index Chart: The Six Bands, the Conversion Math Behind the Numbers, and What Each Band Should Make You Do
The AQI runs 0–500 in six color bands — Good (green) through Hazardous (maroon) — and it's calculated per-pollutant, with the highest s...
Why Is the Air Quality Bad Today? Four Mechanisms Explain Almost Every Bad-Air Day, and the Time Pattern Tells You Which One You’ve Got
Almost every "why is the air bad today" moment in the US resolves to one of four mechanisms: summer-afternoon ozone (car exhaust cookin...