@misc{9224435,
  abstract     = {{Particle-bound reactive oxygen species (ROS) play a key role in mechanisms linking particulate air pollution to adverse health effects through oxidative stress. Understanding the ways in which humans are exposed to ROS is important, and since humans spend most of their time indoors, indoor air quality is a relevant field of research. This thesis investigates particle-bound ROS emitted from typical household activities using offline analytical methods and compares the results with data from a novel online measurement technique, the Particle Into Nitroxide Quencher (PINQ).

Particles were generated in an aerosol chamber from several indoor sources, including candle burning, incense, frying, secondary organic aerosol (SOA) formation from air fresheners, and squalene-ozone reactions representing human skin reacting with ozone, as well as combinations of these sources. Particles were collected on filters and extracted for offline ROS analysis using the dichlorofluorescein (DCFH) assay and spectrofluorometry. The results were compared with real-time ROS measurements during generation obtained using the PINQ, which employs the BPEAnit probe. Additional particle characterization data, including particle size, black carbon concentration, and metal content, were analyzed to explore potential relationships with ROS levels.

The offline method detected particle-bound ROS in all sampled particle types, with particularly high levels observed for candle- and incense-related emissions. However, large variability was found between experiments of the same particle type. Online PINQ measurements showed both positive and negative ROS signals, likely influenced by probe sensitivity and scavenging effects from black carbon. Comparisons between methods reveal limited agreement, highlighting differences in chemical sensitivity, temporal resolution, and methodological constraints.

The results demonstrate that ROS is present on particles in indoor air, hence their health effects are of relevance for further assessment. However, the complexity of assessing particle-bound ROS suggests that no single method can fully capture the oxidative properties of indoor aerosols.}},
  author       = {{Ahrling, Fredric}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Particle bound Reactive Oxygen Species emitted from indoor sources - assessment through offline methods}},
  year         = {{2026}},
}