Fig. 4From: Changes in subjective symptoms and allergy state among medical students exposed to low-level formaldehyde 6 months after completion of a gross anatomy dissection courseIndoor concentrations of FA 30 min after the practice began (figure excerpted partly from Fig. 1 in Ref. [18]). “Measured day” in the horizontal axis means the day when the indoor FA concentration was measured, on every Monday from May to JulyBack to article page