Quantification of formic acid and acetic acid emissions from heritage collections under indoor room conditions. Pt.1: Laboratory and field measurements
The area-specific emission rates of formic acid and acetic acid from heritage objects made of wood and paper were quantified for normal indoor room conditions (23 °C, 50% RH) as well as for cooler (10 °C) and drier (20% RH) conditions. At normal indoor conditions, the emission rate of formic acid and acetic acid together were in the range of 10 to 300 µg m-² h-¹. The emission rate decreased by a factor of 2-4 from wood and paper when lowering the temperature from 23 to 10 °C. The emission rate decreased by more than a factor of 2 when reducing the relative humidity (RH) from 50% to 20%. This corresponds well with field measurements in real storage rooms containing heritage collections. In addition, 36 volatile organic compounds (VOCs) were identified to be released by four paper samples. All the VOCs detected can in general originate from several sources. Therefore, these substances cannot be used as unique degradation markers for paper but rather as an indication of emission sources present in the indoor environment.