CINDAER Composition of indoor aerosols and their role in air quality

Poor air quality is the biggest environmental factor contributing to premature mortality globally. In the recent update to the Global Burden of Disease, long-term exposures to fine particulate matter (PM2.5) was estimated to contribute to 4.9 million premature deaths annually, with cardiopulmonary diseases and cancer being the main contributors. Instrumentation deployed in air quality networks and pollution forecasts can be used to warn when pollution levels outside are high and there is advice on the steps to reduce our personal exposure. However, are we ignoring a much larger risk in our own homes? On average, individuals spend most of their time indoors (80-90 %) and so understanding indoor air quality is vital to estimate where the main sources of pollution exposure occur. There are many possible sources of particles in indoor environments and often levels are higher than outdoors. Combustion sources, such as wood stoves, cooking, candles and smoking can directly emit particles into the air. Volatile organic compounds can be emitted from a wide range of sources including cleaning, personal care, fragrances and even human skin and breath. These compounds can react and form secondary particles, although this route has been very poorly characterised. Finally, outdoor particles can be transferred indoors through open doors and windows as well as through the building fabric itself. Recent work has indicated that as electrification of the vehicle fleet grows, indoor emissions will be increasingly responsible for poor outdoor air quality.

Particle measurements in indoor environments are often done using low cost sensors, that measure either the total mass or number of particles in a given volume. These can provide information on both short-term particle pollution episodes and background concentrations when deployed in a home. However, without extensive monitoring of household activities it can be difficult to assign which sources are most important for exposure studies. One potential way to achieve this, which is commonly used for outdoor aerosols, is to use the chemical composition of aerosols to identify key particle sources. This is difficult in indoor atmospheres due to low concentrations, the small amount of air available to sample and the noise associated with pumps needed for aerosol collection. Therefore, state of the art, highly sensitive methods are needed to separate and identify the chemical components in indoor aerosols.

This overarching aim of this project is to design a new methodology to sample and characterise aerosols from occupied indoor environments. This will involve laboratory studies of different types of particle sources and field deployment of samplers into different types of indoor and outdoor atmospheres. By understanding the chemical tracers in indoor particles, the key sources contributing to poor indoor air quality can be determined.

Specific Aims
- Develop a new sampler suitable for collecting particles in indoor settings
- Validate a high-resolution method to determine the organic composition of organic particles and semi-volatile gases using two-dimensional gas chromatography
- Create chemical fingerprints of different indoor particle sources using laboratory simulations
- Deploy the sampler in a range of different indoor environments
-Identify the key sources of organic particles that degrade indoor air quality and develop interventions to reduce human exposure.

The student will work under the supervision of Prof Jacqui Hamilton and Dr Katherine Manfred. The student will be based in the Wolfson Atmospheric Chemistry Laboratory, part of the Department of Chemistry at the University of York. These were established in 2013 and comprise a state-of-the-art dedicated research building, the first of its kind in the UK.