Variable

Definition

Unit

Source

C

Formaldehyde concentration in air

µg∙m−3

TWA8; STEL from sampling

ET

Exposure time

hour day−1

8 (normal working hour)

EF

Exposure frequency

days year−1

225 (5 days week−1 for 45 weeks year−1)

ED

Exposure duration

years

30 [28]

AT

Averaging time

days

ED × 365 days year−1 (noncancer);

70 years × 365 days year−1 (cancer)

RfC

Inhalation reference concentration

µg∙m−3

3.94 × 10−5 [32]

IUR

Inhalation unit risk

(µg∙m−3)−1

1.3 × 10−5 [34]