Contents lists available at ScienceDirect Building and Environment journal homepage: www.elsevier.com/locate/buildenv Removal performance of formaldehyde by ceiling tiles as sorptive passive panels Mitra Bahri ∗ , Hans Schleibinger, William Render, Olga Naboka Indoor Air Quality Group, Construction Research Center, National Research Council Canada (NRC), Ottawa, Canada ARTICLEINFO Keywords: Indoor air quality Formaldehyde Sorptive passive panels Removal efciency Ceiling tiles ABSTRACT In this study a ceiling tile (CT) was selected as a sorptive passive panel, and the efect of environmental con- ditionsonitsformaldehyderemovalefciencywasevaluated.Experimentswereperformedina0.4m 3 chamber withtheairfowrateof0.2m 3 h −1 ,theairexchangerateofthe0.5h −1 ,andtheloadingratioof0.23m 2 m -3 .The range of temperature humidity levels varied between 21°C ± 2°C–26°C ± 2°C, and 30% ± 5%–75% ± 5%, respectively, to simulate the indoor conditions for Canadian homes during most months of the year. Results demonstrated formaldehyde removal efciencybetween40%and75%dependingontheappliedenvironmental conditions. GC/MS and HPLC trace analyses revealed that only very low concentrations of by-products were formed. The by-product formation increased slightly when exposing the ceiling tile to relatively high relative humidity (RH=75%) and temperature (T=26°C). Given a loading factor of only 0.23m 2 m −3 in our test chamber, which in most scenarios underestimates the loading factor in real settings, our fndings suggest that ceiling tiles used as passive removal panels have the potential to lower formaldehyde concentrations under the Health Canada's guideline for residential settings under real-life conditions. 1. Introduction Indoor air contains a variety of airborne pollutants emitted from diferent sources. Their presence, depending on their concentrations, may afect the health and wellbeing of building occupants [1–3]. Among those volatile pollutants, formaldehyde could be regarded as onethemosthealth-relevantindoorairpollutants[4].Formaldehydeis being emitted from many diferent indoor sources, including latex paints, varnishes, and from oil-based paints that are applied on MDF and HDF [5–9]. It also of-gasses from wooden, especially engineered products and wood smoke [10–12]. The formation of formaldehyde is also attributed to photo-catalytically decomposed paint binders [13,14]. The presence of formaldehyde in indoor environment is of a great concern, because elevated concentrations are linked to several chronic and carcinogenic health efects, allergic reactions, and eye and airway irritations [2,4,15–17]. Long term exposure to formaldehyde increases the risk of respiratory symptoms (i.e. development of asthma) in children between 6 and 36 months, when concentrations exceeds 60μgm −3 [18,19]. WhileaccordingtoHealthCanada'sguidelineforresidentialsettings the maximum level for an 8h exposure to formaldehyde is 50μgm −3 [20], it was shown that the concentration of formaldehyde may signifcantly exceed this level in residential buildings in Canada. For instance,astudyof96homesinQuebecCity(Canada),showedthatthe concentration of formaldehyde can reach 90μgm −3 between Januar- y–April, when windows are usually kept closed due to the cold climate [6].Accordingtothisstudyanelevationinformaldehydeconcentration was observed in homes built after 1970 [5]. A similar study conducted in59homesinPrinceEdwardIsland(Canada)alsoshowedthelevelsof formaldehyde as high as 87.5μgm −3 . In both studies formaldehyde concentrations in 20% of homes exceeded the Canadian target value of 60mgm −3 . So far, several methods have been proposed for the removal of formaldehyde. Among those, increased mechanical ventilation, ad- sorbent- and catalytic-based flters are the most frequently studied [21–25]. However, using these methods requires additional mechanical force which is associated with an increase in energy consumption [21]. Toovercomethisdisadvantage,theapplicationofindoorpassivepanels has been proposed [26,27]. Passive panels (PPs), also known as passive removal materials (PRMs), are emerging materials designed for the removal of indoor pollutants without the requirement of any additional energy input beyond normal building operations [28]. These materials can be designed in diferent types and features including ceiling tiles, wallboards, wallpapers, paint, fooring, etc. https://doi.org/10.1016/j.buildenv.2019.106172 Received 12 March 2019; Received in revised form 16 May 2019; Accepted 29 May 2019 ∗ Corresponding author. Indoor Air Quality (IAQ) Group, Construction Research Center, National Research Council of Canada (NRC), M-24, 1200 Montreal Road, Ottawa, K1A 0R6, Canada. E-mail address: mitra.bahri@nrc-cnrc.gc.ca (M. Bahri). Building and Environment 160 (2019) 106172 Available online 31 May 2019 0360-1323/ Crown Copyright © 2019 Published by Elsevier Ltd. All rights reserved. T