Car

Why this carrier here

A parked car reaches 55 C to 70 C in summer sun and drops to below freezing in winter. Plastic, vinyl and upholstery outgas as the cabin heats, and those compounds read as the car's own smell. Fragrance added on top has to survive both the heat cycle and the outgassing.

The cabin is the smallest volume in the register, and it is fully enclosed. A carrier chosen for a living room will be overwhelming here within one trip. Divide the household rung by two and work up, never down.

Nothing liquid in an open vessel, nothing wax that softens below 60 C, and nothing that rattles loose under braking. A flat carrier clipped or strapped into a vent or console recess is the only format that survives summer.

Same room, other rung

Rung	Covers	One fill lasts	Rung matrix
L1	Barely there 1–5 m2	1-5 m2 of treated surface or enclosed volume; one sachet, one small plaque, two sprays on a cushion.	A 32 g plaque clipped to a vent in a cabin that swings 22 C
L2	Close range 3–12 m2	3-12 m2; one 40-60 g wax tablet, one 60-90 g plaque, a four-reed diffuser, or three sprays on upholstery.	in preparation
L3	Half the room 10–26 m2	10-26 m2; a six- to eight-reed diffuser, two plaques at opposite ends, or a diffuser plus a stone.	in preparation
L4	Whole room 18–30 m2	18 m2 and up, or any open-plan volume; two eight-reed diffusers, a diffuser plus two stones, or a diffuser plus a textile pass.	in preparation

1 live plan(s)

• A 32 g plaque clipped to a vent in a cabin that swings 22 C (L1 · 41 d · CNY 12)