A5030021627- Infection Control and Ventilation
- Inhalation and Respiratory Drug Delivery
- COVID-19 and healthcare impacts
- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Microencapsulation and Drying Processes
- Atmospheric aerosols and clouds
- Infection Control in Healthcare
- Particle Dynamics in Fluid Flows
- Airway Management and Intubation Techniques
- nanoparticles nucleation surface interactions
- Aerosol Filtration and Electrostatic Precipitation
- Air Quality Monitoring and Forecasting
- Climate Change and Health Impacts
- Thermal Regulation in Medicine
- Combustion and flame dynamics
- Dental Research and COVID-19
- Respiratory viral infections research
- Fire effects on ecosystems
- COVID-19 epidemiological studies
- Atmospheric Ozone and Climate
- Crystallization and Solubility Studies
- Combustion and Detonation Processes
- Surface Modification and Superhydrophobicity
- Electrowetting and Microfluidic Technologies
University of Bristol
2019-2024
University of British Columbia
2022-2024
Stemcell Technologies
2024
University of Surrey
2024
At Bristol
2021
North Bristol NHS Trust
2020
Durham University
2015
The potential aerosolised transmission of severe acute respiratory syndrome coronavirus-2 is global concern. Airborne precaution personal protective equipment and preventative measures are universally mandated for medical procedures deemed to be aerosol generating. implementation these having a huge impact on healthcare provision. There currently lack quantitative evidence the number size airborne particles produced during aerosol-generating inform risk assessments. To address this gap, we...
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has resulted in an unprecedented shutdown social and economic activity, with the cultural sector particularly severely affected. Restrictions on musical performances have arisen from a perception that there is significantly higher risk of aerosol production singing than speaking, based upon high-profile examples clusters COVID-19 following choral rehearsals. However, comparing generation different types vocalization,...
Aerosols and droplets from expiratory events play an integral role in transmitting pathogens such as SARS-CoV-2 infected individual to a susceptible host. However, there remain significant uncertainties our understanding of the aerosol droplet microphysics occurring during drying sedimentation effect on outcomes. Here, we apply new treatment for microphysical behavior respiratory fluid evaporation/sedimentation model assess impact distance, time scale, particle phase. Above 100 μm initial...
Introduction continuous positive airway pressure (CPAP) and high-flow nasal oxygen (HFNO) provide enhanced delivery respiratory support for patients with severe COVID-19. CPAP HFNO are currently designated as aerosol-generating procedures despite limited high-quality experimental data. We aimed to characterise aerosol emission from compare breathing, speaking coughing. Materials methods Healthy volunteers were recruited breathe, speak cough in ultra-clean, laminar flow theatres followed by...
It is now generally accepted that SARS-CoV-2 can be spread by aerosols as well larger droplets from the upper respiratory tract, although relative importance of aerosol transmission remains incompletely answered.1Pöhlker ML Krüger OO Förster J-D et al.Respiratory and in infectious diseases.arXiv. 2021; (published online 1 March.)http://arxiv.org/abs/2103.01188Google Scholar Despite this, current UK infection control guidance for hospitals centred on premise are only generated specific...
Respiratory particles produced by breathing, coughing, and speaking or generated during medical procedures serve as important routes for disease transmission. Characterizing the number of well their size distribution is fundamental guiding policy on infection control. However, sampling such carries inherent challenges. are polydisperse in size, temporally spatially variable, emitted very low concentrations, usually lower than preexisting aerosol concentration indoor environments. In...
Industrial processes such as spray drying of pharmaceutical and food products often involve the aerosol droplets containing colloidal suspensions into powdered microparticles desired properties. The morphology surface properties final dry products/microparticles obtained after process are strongly influenced by parameters initial droplet composition conditions. In particular, microparticle can be dependent on dimensionless Péclet number (Pe), which expresses relative competition between...
Objective To determine if oesophago-gastro-duodenoscopy (OGD) generates increased levels of aerosol in conscious patients and identify the source events. Design A prospective, environmental monitoring study, undertaken an ultraclean environment, on undergoing OGD. Sampling was performed 20 cm away from patient’s mouth using optical particle sizer. Aerosol during OGD were compared with tidal breathing voluntary coughs within subject. Results Patients bariatric surgical assessment recruited...
Background Risk of aerosolisation SARS-CoV-2 directly informs organisation acute healthcare and PPE guidance. Continuous positive airways pressure (CPAP) high-flow nasal oxygen (HFNO) are widely used modes delivery respiratory support for patients with severe COVID-19, both considered as high risk aerosol generating procedures. However, there limited quality experimental data characterising during support. Methods Healthy volunteers were recruited to breathe, speak, cough in ultra-clean,...
Abstract. Secondary organic aerosol (SOA) constitutes a large fraction of atmospheric aerosol. To assess its impacts on climate and air pollution, knowledge the number phases in internal mixtures different SOA types is required. Atmospheric models often assume that form single phase when mixed. Here, we present visual observations formed after mixing anthropogenic biogenic types. Mixing generated environmental chambers with oxygen-to-carbon (O/C) ratios between 0.34 1.05, found 6 out 15 two...
Smoke particles generated by burning biomass consist mainly of organic aerosol termed (BBOA). BBOA influences the climate scattering and absorbing solar radiation or acting as nuclei for cloud formation. The viscosity phase behavior (i.e., number type phases present in a particle) are properties that expected to impact several climate-relevant processes but remain highly uncertain. We studied using fluorescence microscopy showed comprise two (a hydrophobic hydrophilic phase) across wide...
The simultaneous evaporation and condensation of multiple volatile components from multicomponent aerosol droplets leads to changes in droplet size, composition temperature. Measurements models that capture predict these dynamic processes are key understanding microphysics a broad range contexts. We report measurements the kinetics (initially ∼25 μm radius) formed mixtures ethanol water levitated within electrodynamic balance over timescales spanning 500 ms 6 s. into gas phase varied...
The evaporation of liquid solution droplets and solute crystallization can be highly complex is an important problem, particularly in spray drying where powdered products are produced from sprayed droplets, such as the food or pharmaceutical industries. In this work, we study relationship between rates single levitated NaNO3 under varying environmental conditions propensity for nucleation crystals. We use a combination electrodynamic balance to single-droplet kinetics, SEM imaging dried...
The performing arts have been significantly restricted due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. We report measurements of aerosol and droplet concentrations generated when playing woodwind brass instruments comparisons with breathing, speaking, singing. These were conducted in a room zero number concentration background 0.5-20 µm diameter size range, allowing clear attribution detected particles specific activities. A total 13 examined across 9...
Summary Many guidelines consider supraglottic airway use to be an aerosol‐generating procedure. This status requires increased levels of personal protective equipment, fallow time between cases and results in reduced operating theatre efficiency. Aerosol generation has never been quantitated during use. To address this evidence gap, we conducted real‐time aerosol monitoring (0.3–10‐µm diameter) ultraclean theatres insertion removal. showed very low background particle concentrations (median...
Heterogeneous reactions occurring between ozone and films or particles containing skin oil cooking can be a sink of source organic compounds indoors with negative health effects. To predict this heterogeneous chemistry, information on the phase behavior (number types phases) within these particles, its evolution during exposure, is needed. In work, we used optical microscopy to directly observe proxies for (diameters 110–220 μm) exposure O3. As proxy oil, multicomponent mixture unsaturated...
Aerosol generating procedures (AGPs) are defined as any procedure releasing airborne particles <5 μm in size from the respiratory tract. There remains uncertainty about which dental constitute AGPs. We quantified aerosol number concentration generated during a range of periodontal, oral surgery and orthodontic using an aerodynamic particle sizer, measures concentrations distribution across 0.5–20 diameter range. Measurements were conducted environment with sufficiently low background to...
A quantitative understanding of the evaporative drying kinetics and nucleation rates aqueous based aerosol droplets is important for a wide range applications, from atmospheric aerosols to industrial processes such as spray drying. Here, we introduce numerical model interpreting measurements evaporation rate phase change free made using single particle approach. We explore sodium chloride nitrate solution droplets. Although salt observed reproducibly crystallize at all rates, can lose...
Summary Manual facemask ventilation, a core component of elective and emergency airway management, is classified as an aerosol‐generating procedure. This designation based on one epidemiological study suggesting association between ventilation transmission during the SARS‐CoV‐1 outbreak in 2003. There no direct evidence to indicate whether high‐risk procedure for aerosol generation. We conducted monitoring routine with intentionally generated leak anaesthetised patients. Recordings were made...
Pulmonary function tests are fundamental to the diagnosis and monitoring of respiratory diseases. There is uncertainty around whether potentially infectious aerosols produced during testing there limited data on mitigation strategies reduce risk staff. Healthy volunteers patients with lung disease underwent standardised spirometry, peak flow FE NO assessments. Aerosol number concentration was sampled using an aerodynamic particle sizer optical sizer. Measured aerosol concentrations were...
In the COVID–19 pandemic, billions are wearing face masks, in both health care settings and public. Which type of mask we should wear what situation, is therefore important. There three basic types: cotton, surgical, respirators (e.g., FFP2, N95 similar). All essentially air filters worn on face. Air filtration relatively well understood, however, have almost no direct evidence relative role played by aerosol particles differing sizes disease transmission. But if virus concentration assumed...