Each month we welcome a guest blog post from our Scoping Studies, to find out more about the air quality issue they are researching and how STFC capabilities are being used. This month, Dr Sari Budisulistiorini shares the aims and background to her team’s project.

Wildfire events are occurring worldwide due to dry and warm conditions linked to climate change. Wildfires are a major biomass burning source that makes up a substantial amount of global aerosol particles. Aerosols are a collection of microscopic liquid droplets and solid particles that are suspended in the air. Moreover, they can scatter or absorb the incoming solar radiation depends on their physicochemical characteristics (Figure 1).1 Besides climate impacts, exposure to aerosols cause adverse respiratory effects, such as lung inflammation, which adversity and characteristics related to the aerosols physicochemical properties.2

Biomass burning emits primary carbonaceous aerosol (black carbon and primary organic aerosol) and inorganic and organic vapour that are precursors to secondary organic aerosol formation. The primary and secondary organic aerosols make up the total organic aerosol from biomass burning. Moreover, previous studies reported that spectral and chemical characteristics of biomass burning organic aerosol are close to humic-like species, which has unique spherical morphology, very low volatility characteristic, and unusual stability in the atmosphere.3 However, these characteristics evolve because of chemical reactions in the atmosphere/aging process, such as photooxidation and ozonolysis.4 Therefore, physicochemical characterisation of atmospherically aged biomass burning organic aerosol is important to provide a clearer picture of their impacts.

The Biomass Burning Aerosol Impacts study aims to develop a holistic approach for characterising biomass burning aerosol and assessing their impacts on climate and human health. We will (i) characterise organic molecules composition and structure of biomass burning organic aerosol using high-resolution spectrometry and spectroscopy, (ii) measure the refractive index, and (iii) assess the preliminary biological effects. It is key that the OA is studied as a component in the PM2.5 to replicate the original conditions accurately. Hence, we will use PM2.5 from Singapore during an episode of wildfire, previously reported containing substantial light-absorbing organic constituents.5 The study will be conducted at the University of York, and STFC Central Laser Facility and ISIS Muon and Neutron Source for the physicochemical characteristics experiment and at Public Health England for the biological response experiment.

Biomass burning is part of daily life and impacts outdoor and indoor air quality. Hence, understanding the climate and health impacts of biomass burning would provide clearer pictures to the government locally and globally for improving air quality policy related to biomass burning and wildfires. Additionally, the high-resolution spectrometry and in-vitro approaches can be expanded to other air pollution sources, for example, wood-burning stoves and secondary organic aerosol. Thus, these methods would advance scientific knowledge and capabilities.

Figure 1. Scheme of wildfires and biomass burning aerosol particles interactions with climate change and air quality.
Figure 2. (Top panel) Chromatograms at near-UV and visible wavelengths of ambient aerosols collected when OA mass concentrations are (a) high (79 μg m–3) and (b) low (12 μg m–3). (Bottom panel, c) Light-absorbing brown carbon constituents and organic aerosol mass concentration were measured when Singapore was affected by smoke from Indonesia peatland fires in 2015. Points labelled a and b in the bottom panel refer to the top panels as well as the periods when ambient OA concentrations are high and low, respectively. Adapted from Budisulistiorini et al.5

Project team:


  1. IPCC. (Cambridge University Press, 2013)
  2. Guo, C. et al. Nanotoxicology 13, 733–750 (2019)
  3. Laskin, A. et al. Chemical Reviews (2015)
  4. Hems, R. F. et al. ACS Earth and Space Chemistry 5, 722–748 (2021)
  5. Budisulistiorini, S. H. et al. Environmental Science & Technology 51, 4415–4423 (2017)