Air pollution can damage heritage collections.
This study examines the air quality performance
in one store with mechanical ventilation and
in another with semi-passive climate control.
Air pollution was measured with passive diffusion
samplers during summer and winter. The
atmospheric corrosivity was determined gravimetrically
using copper, zinc and lead coupons,
and by a real-time electrical resistance monitor
over one year. The concentration of outdoorgenerated
air pollution was low within both
stores. The emission of formic acid and acetic
acid from internal sources led to higher indoor
concentrations. The total acid concentration
was 15 μg m-3 in the store with mechanical ventilation
and 97 μg m-3 in the store with semipassive
climate control. The indoor atmospheric
corrosivity was determined as very low by both
methods. The study demonstrated that stores
using mechanical ventilation with air filtration
and semi-passive climate control provide acceptable
air quality for the preservation of heritage
collections.