Acetic and formic acids emitted from wood samples and their effect on selected materials in museum environments

The concentrations of acetic acid and formic acid vapours emitted by a number of wood samples held in sealed environments were measured to assess differences between hardwood and softwood species. Three cases studies are reported where sodium formate, lead formate and acetate-based efflorescences were identified on glass, lead and calcareous artefacts held in heritage environments with elevated acetic acid and formic acid vapours. Simulated experiments were undertaken to assess the affect of formic acid vapour on limestone, egg shell, copper, lead and brass coupons and it was confirmed that porous limestone preferentially scavenged formic acid vapours from air.