Pet dander: what the PM₁₀ trace shows

Pet "dander" is not the hair itself. It is the dried skin flakes and saliva proteins that cling to hair and fall off as the animal moves. The dominant allergens are Fel d 1 (cat, in sebaceous secretions and saliva) and Can f 1 (dog). Cat allergen is famously persistent: a cat-owning household will have measurable Fel d 1 in dust six months after the cat leaves. Dog allergen drops faster.

Particle size matters for interpretation. Fel d 1 carrier particles span 2 to 10 µm: a range that puts them right in the middle of PM₁₀, with a meaningful PM_2.5 fraction. They are sticky enough to bind to walls, fabrics, and HVAC filters; they aerosolize readily when surfaces are disturbed.

In the dashboard sparkline, pet dander reads as broad PM₁₀ elevation that rises when the household is active and falls overnight: the inverse of the "everyone in the bedroom" CO₂ pattern. When PM₁₀ is elevated but PM_2.5 stays moderate and VOCs/NO_x stay flat, dander or dust is the most likely source, not combustion.

Interventions, in rough order of effectiveness: HEPA filtration sized for the room (CADR ≥ room area × 5), a MERV-13 HVAC filter, weekly washing of bedding, allergen-impermeable bedding covers, and keeping pets out of bedrooms. AAAAI reviews the evidence, and gently dispels the "hypoallergenic breed" myth (the protein is the protein; no breed lacks it).

This is environmental information, not medical advice. The dashboard's readings help you make decisions about the air in your space. They do not diagnose conditions, interpret symptoms, or replace conversations with your physician. If symptoms persist, worsen, or coincide with a known exposure, talk to a healthcare professional. See the AI's medical-advice scope.