Condition category
Infections and Infestations
Date applied
Date assigned
Last edited
Retrospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Aerosol generation occurs when tiny droplets of liquid are suspended in the air. Aerosols can be generated during many medical procedures. Some procedures might produce more aerosols than others, and droplets of different sizes, but this is largely unknown at the moment. However, aerosols can carry viruses, like coronavirus, which risks further infections if inhaled by healthcare staff or other patients. This study aims to determine how aerosol is produced in healthcare settings and how it settles and disperses. This is critical, as it is increasingly recognised that COVID-19 can spread via aerosol. Many healthcare procedures (such as intubation) are considered potentially ‘aerosol-generating’, which means healthcare workers have to wear personal protective equipment (PPE) and there are delays in procedures. This study aims to measure whether and how much aerosol is actually generated in these procedures, how long it takes to settles, and whether it is possible to mitigate the risk of aerosol spread in hospitals. This will aim to inform whether the PPE worn during these procedures is correct, and what can be done to try and limit risk to staff and patients of aerosol transmission of coronavirus. This study will be performed in hospitals, specifically at North Bristol NHS Trust and University Hospital Bristol and Weston NHS Foundation trust, using equipment from the School of Chemistry at the Bristol Aerosol Research Centre to measure aerosol.

Who can participate?
People will be recruited from two sources: patients who are undergoing procedures as part of routine care in hospitals already, and healthy volunteers. Healthy volunteers must be adults (>18) and must not have COVID-19 symptoms.

What does the study involve?
The study involves measurement of aerosol using small machines, about the size of a computer, attached to funnels that will measure aerosol in the air near participants. Routine data such as age, sex, and BMI will be recorded. No follow up will be arranged, and no other medical procedures will be performed.

What are the possible benefits and risks of participating?
There are no potential benefits of entering, apart from helping the researchers. There are no anticipated negative effects or side effects.

Where is the study run from?
The study is a collaboration between North Bristol NHS Trust, the University of Bristol, and University Hospital Bristol and Weston NHS Foundation Trust (UK)

When is the study starting and how long is it expected to run for?
September 2020 to September 2021

Who is funding the study?
National Institute for Health Research and the UK Research Institutes (NIHR-UKRI) (UK)

Who is the main contact?
Fergus Hamilton

Trial website

Contact information



Primary contact

Dr Fergus Hamilton


Contact details

Infection Science
Pathology Services
Southmead Hospital
BS10 5NB
United Kingdom
+44 (0)7743165499



Additional contact

Dr Fergus Hamilton


Contact details

Infection Science
Pathology Services
Southmead Hospital
BS10 5NB
United Kingdom
+44 (0)07743165499

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number

3.4, IRAS 288784, CPMS 47097

Study information

Scientific title

AERosolisation And Transmission Of SARS-CoV-2 in Healthcare Settings (AERATOR)



Study hypothesis

The aim of this study is to quantify the flux, concentration, size distribution, and persistence of aerosol generated by a diverse set of clinical procedures across various settings, and assess heterogeneity between operator, equipment, and room.

Ethics approval

Approved 18/09/2020, North West Greater Manchester Central REC (Third Floor, Barlow House, Minshull Street, M1 3DZ, UK; +44 (0)207 104 8193, +44 (0)207 104 8007, +44 (0)207 104 8208;, REC ref: 20/NW/0393

Study design

Aerosol and environmental sampling study

Primary study design


Secondary study design

Aerosol and environmental sampling study

Trial setting


Trial type


Patient information sheet

Not available in web format, please use contact details to request a participant information sheet


COVID-19 (SARS-CoV-2 infection)


The AERATOR study will be carried out using specialist equipment in operating theatres and wards to measure real-life aerosol generation in five clinical settings: dental, orthopaedic, respiratory, critical care and ophthalmology. By using specialist equipment, only available at the University of Bristol, the research team will also investigate how long coronavirus survives while airborne and how environmental conditions impact on the infectivity of the virus.

The research will also advise guidelines on the appropriate level of PPE for staff, as well as the length of time the aerosol is present for and how it spreads in a real-world clinical setting.

The total duration of observation for each participant is around 15 minutes to 1 hour. The trial will run for 1 year.

Intervention type



Not Applicable

Drug names

Primary outcome measure

1. Distribution of aerosol produced during routine or simulated procedures measured using Aerodynamic Particle Sensors during the procedure, and for up to 10 minutes after
2. Distribution of aerosol produced during routine or simulated procedures measured using Optical Particle Sensors during the procedure, and for up to 10 minutes after

Secondary outcome measures

Distribution of aerosol produced and dissemination measured with Aerodynamic and Optical Particle sensors across a clinical room during procedures and for up to 1 hour after

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

1. Undergoing procedure that is potentially aerosol-generating
2. Aged over 18
3. Have capacity

Healthy volunteers:
1. Have capacity to consent to the study
2. Aged over 18

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Unable to read/understand PIS (either printed version or via translator)
2. Unable to consent

Healthy volunteers:
1. Flu-like symptoms (fevers, temperature, new cough, sore throat, loss of smell, breathing difficulties) in the 48 hours prior to study enrolment
2. Clinical contraindication to the procedure being performed

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

North Bristol NHS Trust
Southmead Hospital Southmead Road Westbury-on-Trym
BS10 5NB
United Kingdom

Trial participating centre

University Hospitals Bristol and Weston NHS Foundation Trust
Upper Maudlin Street, Bristol
United Kingdom

Sponsor information


North Bristol NHS Trust

Sponsor details

Learning and Research Building
Level 3
Southmead Hospital
BS10 5NB
United Kingdom
+44 (0)117950505

Sponsor type

Hospital/treatment centre



Funder type


Funder name

National Institute for Health Research

Alternative name(s)


Funding Body Type

government organisation

Funding Body Subtype

National government


United Kingdom

Funder name

UK Research and Innovation

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Planned publication in a high-impact peer-reviewed journal. All articles will be disseminated rapidly to key stakeholders, and where possible, via pre-print servers.

IPD sharing statement
Trial-level data will be held at the Bristol Aerosol Research Centre, as this will simply be aerosol measurements attached to the age, sex, and BMI. The researchers are unable to share patient-level data due to sponsor-level agreements around sharing trial data. Interested parties can contact Fergus Hamilton ( to discuss further.

Intention to publish date


Participant level data

Not expected to be available

Basic results (scientific)

Publication list

Publication citations

Additional files

Editorial Notes

01/10/2020: Trial's existence confirmed by the NIHR.