Characterization of indoor air quality by canister sampling and TD-GC-MS analysis

摘要

A canister is a vacuumed container designed for air sampling. This technology is available for a range of air sampling applications, including personal air sampling. Canisters have a number of interesting features but are still not much used in Europe. We have explored the value of canisters in our field of interest: indoor air quality (IAQ). Objective Evaluation of the measurement of volatile organic compounds (VOCs)in indoor air by canister sampling followed by analysis on a thermal desorption gas chromatograph mass spectrometer (TD-GC-MS) system. We performed an exploratory study on the impact of emissions from emergency helicopters and testing diesel-fueled emergency power supplies as potential sources of contamination of our hospitals' IAQ. Method For the VOC measurements air samples were collected using Entech Silonite canisters equipped with CS1200 Silonite coated samplers or grab samplers (Interscience). For calibration, we used TO14 and T015 calibration standard VOC mixtures that were provided in gas cylinders. For calibration the cylinder was connected to an air server (Series 2, Markes). The analytical instrument consisted of a thermal desorber (Unity 2, Markes) and a gas chromatograph mass spectrometer (Focus/ISQ, Thermo). We collected samples of 100 - 250 mL per canister. Results The limit of quantification for VOCs was 0.1 μg/m3. Healthcare workers were asked to collect a grab sample when they picked up a kerosene odor. Simultaneously a sample was collected at a service building near the helicopter platform. In a second campaign we collected indoor air samples at two operation rooms before and during the test run of an emergency power supply. These measurements were compared to the results of a reference sample that was collected at the exhaust outlet of the power supply. Relating to the indoor air quality in the hospital, the concentrations of acetone, isopropanol and ethanol were somewhat elevated due to cleaning and disinfection practices. We did not detect VOCs in the indoor air that were characteristic for helicopter emissions or diesel exhaust. Conclusion Canisters can be used for self-assessment grab sampling in addition to the conventional use of air sampling pumps.