PMID- 33217439 OWN - NLM STAT- MEDLINE DCOM- 20210603 LR - 20231213 IS - 1096-0953 (Electronic) IS - 0013-9351 (Linking) VI - 198 DP - 2021 Jul TI - Chemical changes in thirdhand smoke associated with remediation using an ozone generator. PG - 110462 LID - S0013-9351(20)31359-1 [pii] LID - 10.1016/j.envres.2020.110462 [doi] AB - Ozonation is a common remediation approach to eliminate odors from mold, tobacco and fire damage in buildings. Little information exists to: 1) assess its effectiveness; 2) provide guidance on operation conditions; and 3) identify potential risks associated with the presence of indoor ozone and ozonation byproducts. The goal of this study is to evaluate chemical changes in thirdhand smoke (THS) aerosols induced by high levels of ozone, in comparison with THS aerosols aged under similar conditions in the absence of ozone. Samples representing different stages of smoke aging in the absence of ozone, including freshly emitted secondhand smoke (SHS) and THS, were collected inside an 18-m(3) room-sized chamber over a period of 42 h after six cigarettes were consumed. The experiments involved collection and analysis of gas phase species including volatile organic compounds (VOCs), volatile carbonyls, semivolatile organic compounds (SVOCs), and particulate matter. VOC analysis was carried out by gas chromatography/mass spectrometry with a thermal desorption inlet (TD-GC/MS), and volatile carbonyls were analyzed by on-line derivatization with dinitrophenylhydrazine (DNPH), followed by liquid chromatography with UV/VIS detection. SVOCs were extracted from XAD-coated denuders and Teflon-coated fiberglass filters in the absence of ozone. In those extracts, tobacco-specific nitrosamines (TSNAs) and other SVOCs were analyzed by gas chromatography with positive chemical ionization-triple quadrupole mass spectrometric detection (GC/PCI-QQQ-MS), and polycyclic aromatic hydrocarbons (PAHs) were quantified by gas chromatography with ion trap mass spectrometric detection (GC/IT-MS) in selected ion monitoring mode. Particulate matter concentration was determined gravimetrically. In a second experiment, a 300 mg h(-1) commercial ozone generator was operated during 1 h, one day after smoke was generated, to evaluate the remediation of THS by ozonation. VOCs and volatile carbonyls were analyzed before and after ozonation. Extracts from fabrics that were exposed in the chamber before and after ozonation as surrogates for indoor furnishings were analyzed by GC/IT-MS, and aerosol size distribution was studied with a scanning mobility particle sizer. Ozone concentration was measured with a photometric detector. An estimated 175 mg ozone reacted with THS after 1 h of treatment, corresponding to 58% of the total O(3) released during that period. Fabric-bound nicotine was depleted after ozonation, and the surface concentration of PAHs adsorbed to fabric specimens decreased by an order of magnitude due to reaction with ozone, reaching pre-smoking levels. These results suggest that ozonation has the potential to remove harmful THS chemicals from indoor surfaces. However, gas phase concentrations of volatile carbonyls, including formaldehyde, acetaldehyde and acetone were higher immediately after ozonation. Ultrafine particles (UFP, in most cases with size <60 nm) were a major ozonation byproduct. UFP number concentrations peaked shortly after ozonation ended, and remained at higher-than background levels for several hours. Based on these results, minimum re-entry times after ozone treatment were predicted for different indoor scenarios. Clearly defining re-entry times can serve as a practical measure to prevent acute exposures to ozone and harmful ozonation byproducts after treatment. This study evaluated potential benefits and risks associated with THS remediation using ozone, providing insights into this technology. CI - Copyright (c) 2020 Elsevier Inc. All rights reserved. FAU - Tang, Xiaochen AU - Tang X AD - Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. Electronic address: XTang@lbl.gov. FAU - Gonzalez, Noelia Ramirez AU - Gonzalez NR AD - Institut d'Investigacio Sanitaria Pere Virgili, Universitat Rovira i Virgili, Department of Electronic Engineering, Tarragona, Spain; CIBER de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain. FAU - Russell, Marion L AU - Russell ML AD - Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. FAU - Maddalena, Randy L AU - Maddalena RL AD - Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. FAU - Gundel, Lara A AU - Gundel LA AD - Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. FAU - Destaillats, Hugo AU - Destaillats H AD - Indoor Environment Group, Lawrence Berkeley National Laboratory, Berkeley, CA, USA. Electronic address: HDestaillats@lbl.gov. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PT - Research Support, U.S. Gov't, Non-P.H.S. DEP - 20201118 PL - Netherlands TA - Environ Res JT - Environmental research JID - 0147621 RN - 0 (Smoke) RN - 0 (Tobacco Smoke Pollution) RN - 66H7ZZK23N (Ozone) SB - IM MH - Gas Chromatography-Mass Spectrometry MH - *Ozone MH - *Percutaneous Coronary Intervention MH - Smoke MH - Nicotiana MH - *Tobacco Smoke Pollution/analysis OTO - NOTNLM OT - Aerosol aging OT - Nicotine OT - Ozone OT - TSNA OT - Thirdhand cigarette smoke EDAT- 2020/11/21 06:00 MHDA- 2021/06/04 06:00 CRDT- 2020/11/20 20:08 PHST- 2020/06/19 00:00 [received] PHST- 2020/10/13 00:00 [revised] PHST- 2020/11/09 00:00 [accepted] PHST- 2020/11/21 06:00 [pubmed] PHST- 2021/06/04 06:00 [medline] PHST- 2020/11/20 20:08 [entrez] AID - S0013-9351(20)31359-1 [pii] AID - 10.1016/j.envres.2020.110462 [doi] PST - ppublish SO - Environ Res. 2021 Jul;198:110462. doi: 10.1016/j.envres.2020.110462. Epub 2020 Nov 18.