Oxidative reactivity and physicochemical characteristics of mixtures of airborne particles from indoor and outdoor sources in indoor environments

We will determine reactive oxygen species (ROS) formation potential, a marker of toxicity, and physicochemical characteristics of mixtures of airborne particle originating from indoor and outdoor sources.

Focus on indoor environments is motivated by 90% of the time we spend indoors, confirmed high concentration of mixtures indoors and recent findings indicating higher toxicity of airborne particles indoors compared to outdoors. Toxicity of mixtures can be different than of the individual components and remains unknown in indoor environments.

Measurements will be carried out in laboratory and inside and outside occupied residences. ROS generated by particles will be measured in real time with a recently developed method.

Characteristics of particles and gases and their interactions will be determined in real time with two mass spectrometers that quantify chemical composition of particles and gases. Role of particles as carriers of pollutants for lung deposition will be studied.

We will assess how organic coating and chemical composition of the core of the particle affects ROS formation potential.

Analyses of correlation between ROS formation potentials and characteristics of various mixtures will identify properties that indicate toxicity and hence are of concern for human health. Results will contribute to validation of indoor air chemistry models through cooperation with international experts.

Outcomes will guide control measures to minimise human toxic exposure indoors.