- Professor Paul Monks
- Dr Rebecca Cordell
- Dr Gareth Evans (Public Health England)
- Dr Karen Exley (Public Health England)
People spend 80-90% of their time indoors, yet relatively little is known about exposures to poor air quality indoors at home or in work. Volatile organic compounds (VOCs) are ubiquitous in indoor and outdoor air but measurement information about their concentrations in homes and workplaces is very limited. Exposure to VOCs is associated with different health endpoints including irritation of the eyes, nose and throat, headache, loss of coordination and nausea and at high concentrations they may cause damage to liver, kidney and central nervous system. Some VOCs are suspected human carcinogens.
In the last decade affordable three-dimensional (3D) desktop printers have been developed to make prototypes of machine components, architectural models, medical prosthetic devices or for design and fabrication of clothing and footwear. These printers are being used widely in educational establishments, small businesses, and by members of the public.
Previous research found that 3D printers that build objects by melting polymer filaments release large numbers tiny organic soot particles, VOCs, and some hazardous chemicals known to cause asthma. This research was used to develop a good practice guide for schools on reducing emissions from desktop 3D polymer printers.
This PhD will undertake research into a new type of light sensitive liquid resin 3D Stereolithography (SLA) printer. This builds components very quickly using focussed intense light beams to polymerise layers of the resin. These printers employ an open liquid resin bath containing solvents and small molecular weight organic chemicals such as plasticisers, bonding agents, and colouring compounds which may release VOC's.
The research will determine the concentrations and types of VOCs from these printers released using gas chromatography-mass spectrometry (GC-MS) analysis. It will investigate the potential risks to health of employees using these printers and examine methods to minimise the emissions so these printers can be used safely.
This research will provide opportunities to develop research skills in analytical chemistry, indoor air quality monitoring, and new polymer based additive printers. The successful applicant will be supported by scientific advisers from Public Health England (Dr Karen Exley) in studies of air quality (indoor and outdoor) and public health. Also, by the Health and Safety Executive Laboratory in Buxton (Dr Gareth Evans and Samantha Hall) who undertook the previous research into safe use of desktop filament polymer 3D printers.
Year 1: Review of literature and development of suitable laboratory and statistical analysis methods for VOC emissions from 3D SLA printers using GC-MS.
Year 2: Laboratory emission studies using 3D SLA printers to quantify and characterise specific VOCs and small particle emissions. Undertaking in vitro assays to assess the toxicity of specific VOCs on human lung cells. Preparations for workplace 3D printer emissions study and assessing employee health effects with ethical approval.
Years 3: Carrying out the workplace VOC emissions monitoring and health study. Testing different printer enclosures to reduce the emissions from 3D SLA printers. Working with an expert panel to develop a good practice guide for schools and businesses using SLA 3D printers. Submitting PhD thesis and publication of research.
The successful student will develop a range of skills in GC-MS analysis, sampling VOCs and air particles, 3D SLA printers and design of equipment to reduce these emissions. This inter-disciplinary and applied research will involve close collaboration with printer manufacturers, manufacturing technology centres, the HSE Laboratory and PHE. They will undertake laboratory work, analytical chemistry, data analysis, exposure science, toxicology and health studies as well as insight into the development of good practice guidance. The ideal student should have experience of some of these fields, but they will be provided with training.
- Public Health England. Indoor air quality guidelines for selected Volatile Organic Compounds (VOCs) in the UK. Public Health England, London, UK 2019.
- Shrubsole C et al. IAQ guidelines for selected volatile organic compounds (VOCs) in the UK. Building and Environment 2019;165:106382