2.3.1. Test Emission Chamber Experiments

Experiments were carried out inside a small-scale test emission chamber, a hermetically closed glass chemical reactor with a cylindrical shape and with the following dimensions: diameter = 29 cm, height = 61 cm and volume = 0.05 m3. Teflon fans were installed at the top of the chamber to ensure that the air was adequately mixed. The test emission chamber was operated with controlled micro-environmental parameters, according to the relevant ISO standard. For each experiment, temperature and relative humidity were 23 <sup>±</sup> <sup>2</sup> ◦C and 50 <sup>±</sup> 5%, respectively. Air exchange rate (AER) was 0.5 <sup>±</sup> 0.1 h<sup>−</sup>1, which agrees with many European building standards for ventilation in indoor environments [26]. The chamber was supplied with ultrapure compressed air (VOC-free air). Before each experiment, the chamber was cleaned with detergent and rinsed with distilled water, and background samples were taken in order to verify VOC levels. The electric heating bag was introduced inside the chamber, and the test started when the chamber was closed (t = 0). Each experiment lasted 72 h and was carried out with the heating bag not electrically supplied ('not-heating mode') as the test chamber configuration was not suitable to carry out the experiments allowing electrical connections between the warming bag (inside the chamber) and outside. The test emission chamber was provided with two outlet ducts to allow chamber air to be monitored by high temporal resolution instrumentation and/or collected onto adsorbent cartridges. In the present study, Total Volatile Organic Compounds (TVOC) concentration was monitored by means of a high temporal resolution photo-ionization detector (PhoCheck® Tiger, Ion Science Ltd., UK), over the entire duration of the test, in order to verify the achievement of a steady state concentration inside the test emission chamber. VOCs were sampled in duplicate on suitable adsorbent cartridges by means of calibrated sampling pumps (Pocket pump). Adsorbent cartridges consisted of a cylindrical stainless steel net (100 mesh) containing 350 mg Carbograph 4 (35–50 mesh). Air samples were collected at 72 h after the start of the chamber experiment, with a sampling flow rate of 50 mL/min and a sampling time of 100 min, resulting in a collected air volume of 5 L.
