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Emissions of ultrafine particles from five types of candles during steady burn conditions

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DOI

  • Berit B. Rasmussen
  • ,
  • Kai Wang, China Agricultural University
  • ,
  • Johan G. Karstoft
  • Søren N. Skov
  • Morten Køcks, Danish Technological Institute
  • ,
  • Christina Andersen, Lund University
  • ,
  • Aneta Wierzbicka, Lund University
  • ,
  • Joakim Pagels, Lund University
  • ,
  • Peter B. Pedersen, Danish Technological Institute
  • ,
  • Marianne Glasius
  • Merete Bilde

Emissions from candles are of concern for indoor air quality. In this work, five different types of pillar candles were burned under steady burn conditions in a new laboratory scale system for repeatable and controlled comparison of candle emissions (temperature ~25°C, relative humidity ~13%, O2 >18%, air exchange rate 1.9 h−1). Burn rate, particle number concentrations, mass concentrations, and mode diameters varied between candle types. Based on the results, the burning period was divided in two phases: initial (0–1 h) and stable (1–6 h). Burn rates were in the range 4.4–7.3 and 4.7–7.1 g/h during initial and stable phase, respectively. Relative particle number emissions, mode diameters, and mass concentrations were higher during the initial phase compared to the stable phase for a majority of the candles. We hypothesize that this is due to elevated emissions of wick additives upon ignition of the candle together with a slightly higher burn rate in the initial phase. Experiments at higher relative humidity (~40%) gave similar results with a tendency toward larger particle sizes at the higher relative humidity. Chemical composition with respect to inorganic salts was similar in the emitted particles (dry conditions) compared to the candlewicks, but with variations between different candles.

OriginalsprogEngelsk
TidsskriftIndoor Air
Vol/bind31
Nummer4
Sider (fra-til)1084-1094
Antal sider11
ISSN0905-6947
DOI
StatusUdgivet - jul. 2021

Bibliografisk note

Funding Information:
This work is partly funded by the Innovation Fund Denmark (IFD) under File No. 7048-00002A. This study was conducted as part of the Innovation Fund Denmark project CANdle Development for Low Emissions (2017-2020). We thank Innovation Fund Denmark 436 (www.innovationsfonden.dk) for funding. The project has the following partners: Danish Technological Institute, Lund University, Aarhus University, ASP-Holmblad A/S, Coop Denmark A/S, Danwax ApS, European Candle Association ASBL, Liljeholmens Stearinfabriks AB, Promol - Industria de vesla S.A. The candles used were provided by the industrial partners. We thank all partners in the consortium for discussions. We thank the Mechanical Workshop at Department of Chemistry, Aarhus University for assistance on constructing the chamber.

Funding Information:
This study was conducted as part of the Innovation Fund Denmark project CANdle Development for Low Emissions (2017‐2020). We thank Innovation Fund Denmark 436 ( www.innovationsfonden.dk ) for funding. The project has the following partners: Danish Technological Institute, Lund University, Aarhus University, ASP‐Holmblad A/S, Coop Denmark A/S, Danwax ApS, European Candle Association ASBL, Liljeholmens Stearinfabriks AB, Promol ‐ Industria de vesla S.A. The candles used were provided by the industrial partners. We thank all partners in the consortium for discussions. We thank the Mechanical Workshop at Department of Chemistry, Aarhus University for assistance on constructing the chamber.

Funding Information:
This work is partly funded by the Innovation Fund Denmark (IFD) under File No. 7048‐00002A.

Publisher Copyright:
© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

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