CSIRO – Out in the smoke of Prescribed Burns developing smoke emission factors

April 28th, 2020

This year during the planned burning season, Dr. Fabienne Reisen and her extended team ventured into the field to measure and analyse components of smoke emitted by the smouldering combustion phase of logs. The team have provided extensive expertise and flexibility in field and associated laboratory studies related to this work, (Jennifer Powell, Sally Taylor, Suzie Molloy, Christopher Roulston, Min Cheng, Jason Ward and Rob Gillett).

Combustion science is a complicated field with many contributing factors, from the fuel to oxygen content to the temperature of the burn all of which can greatly change what and how much is emitted into our atmosphere, and ultimately our lungs. This gives a larger uncertainty in simulating smoke composition and concentration. the aim of the current study is to develop emission factors for particulate matter from the smouldering condition of eucalypt forests in Australia.

What are smoke measurements used for?

Chemical Transport Models (CTM) and CSIRO’s own AQFx smoke forecasting system rely on emission factors to seed their simulations and to ensure they can adapt to the ever changing conditions during fires and planned burns. By investigating smouldering combustion the aim is to improve emissions from smouldering combustion. Despite the ferocity of flaming combustion, it is relatively short lived when compared to the smouldering of logs which may continue for an extended period after the initial fire front has been contained.

Sampling Methodology

Sampling for this study follows the methodology developed by C. P. Meyer, et al. where the use of a custom build portable backpack sampling system is used. The backpack uses a DustTrak II and a Q-Trak for real time measurements of CO, CO2 and particles. Additional samples are collected on filters and within tedlar bags for a more complete analysis of smoke components once the samples are returned to site.

Planned burns provide close to real world conditions for the measurement of smoke emission factors. We would like to thank the Department of Environment, Land, Water and Planning (DELWP), the Forest Fire Management Victoria (FFM), Parks Victoria and the Country Fire Association (CFA) for their continued assistance in the pursuit of better understanding the world around us.

By Christopher Roulston, Fabienne Reisen