Respiratory aerosols and droplets in the transmission of infectious diseases

Reviews of Modern Physics, Journal Year: 2023, Volume and Issue: 95(4)

Published: Oct. 12, 2023

The pandemic of coronavirus disease 2019 has led to a renewed focus on the physicochemical properties droplets and aerosol particles that are exhaled during breathing, speaking, singing, coughing, sneezing. In this article, respiratory particles, including their number concentrations size distributions, as well formation mechanisms at different sites in system, reviewed. data literature synthesized via parametrization particle distribution using log-normal modes related origin sites.

Language: Английский

---

Open-set deep learning–enabled single-cell Raman spectroscopy for rapid identification of airborne pathogens in real-world environments

Science Advances, Journal Year: 2025, Volume and Issue: 11(2)

Published: Jan. 8, 2025

Pathogenic bioaerosols are critical for outbreaks of airborne disease; however, rapidly and accurately identifying pathogens directly from complex air environments remains highly challenging. We present an advanced method that combines open-set deep learning (OSDL) with single-cell Raman spectroscopy to identify in real-world containing diverse unknown indigenous bacteria cannot be fully included training sets. To test further enhance identification, we constructed the datasets aerosolized bacteria. Through optimizing OSDL algorithms strategies, Raman-OSDL achieves 93% accuracy five target pathogens, 84% untrained bacteria, 36% reduction false positive rates compared conventional close-set algorithms. It offers a high detection sensitivity down 1:1000. When applied real >4600 bacterial species, our identifies single or multiple simultaneously within hour. This tool advances surveilling prevent infection transmission.

Language: Английский

---

Expiratory Aerosol pH: The Overlooked Driver of Airborne Virus Inactivation

Environmental Science & Technology, Journal Year: 2022, Volume and Issue: 57(1), P. 486 - 497

Published: Dec. 20, 2022

Respiratory viruses, including influenza virus and SARS-CoV-2, are transmitted by the airborne route. Air filtration ventilation mechanically reduce concentration of viruses necessary tools for disease mitigation. However, they ignore potential impact chemical environment surrounding aerosolized which determines aerosol pH. Atmospheric gravitates toward acidic pH, enveloped prone to inactivation at strong acidity levels. Yet, expiratory particles its effect on persistence have not been examined. Here, we combine pH-dependent rates A (IAV) SARS-CoV-2 with microphysical properties respiratory fluids using a biophysical model. We find that exhaled into indoor air (with relative humidity ≥ 50%) become mildly (pH ∼ 4), rapidly inactivating IAV within minutes, whereas requires days. If is enriched nonhazardous levels nitric acid, pH drops up 2 units, decreasing 99%-inactivation times both in small below 30 s. Conversely, unintentional removal volatile acids from may elevate prolong persistence. The overlooked role has profound implications transmission mitigation strategies.

Language: Английский

---

Differences in airborne stability of SARS-CoV-2 variants of concern is impacted by alkalinity of surrogates of respiratory aerosol

Journal of The Royal Society Interface, Journal Year: 2023, Volume and Issue: 20(203)

Published: June 1, 2023

The mechanistic factors hypothesized to be key drivers for the loss of infectivity viruses in aerosol phase often remain speculative. Using a next-generation bioaerosol technology, we report measurements aero-stability several SARS-CoV-2 variants concern droplets well-defined size and composition at high (90%) low (40%) relative humidity (RH) upwards 40 min. When compared with ancestral virus, Delta variant displayed different decay profiles. At RH, viral approximately 55% was observed over initial 5 s both variants. Regardless RH variant, greater than 95% lost after min being aerosolized. Aero-stability correlate their sensitivities alkaline pH. Removal all acidic vapours dramatically increased rate decay, 90% 2 min, while addition nitric acid vapour improved aero-stability. Similar artificial saliva growth medium observed. A model predict is proposed: pH exhaled drives loss; salt content limits infectivity.

Language: Английский

---

Opinion: Atmospheric multiphase chemistry – past, present, and future

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(17), P. 9765 - 9785

Published: Sept. 4, 2023

Abstract. Multiphase chemistry occurs between chemicals in different atmospheric phases, typically involving gas–solid and gas–liquid interactions. The importance of multiphase has long been recognized. Its central role extends from acid precipitation stratospheric ozone depletion to its impact on the oxidizing capacity troposphere roles that aerosol particles play driving chemistry–climate interactions affecting human health. This opinion article briefly introduces subject tracks development before after start Atmospheric Chemistry Physics. Most focuses research opportunities challenges field. Central themes are a fundamental understanding at molecular level underpins ability accurately predict environmental change discipline is strongest when tightly connected modeling field observations.

Language: Английский

---

Temperature and indoor environments

Indoor Air, Journal Year: 2022, Volume and Issue: 32(5)

Published: May 1, 2022

From the thermodynamic perspective, term temperature is clearly defined for ideal physical systems: A unique can be assigned to each black body via its radiation spectrum, and of an gas given by velocity distribution molecules. While indoor environment not system, fundamental chemical processes, such as diffusion, partitioning equilibria, reactions, are predictably temperature-dependent. For example, logarithm reaction rate equilibria constants proportional reciprocal absolute temperature. It therefore possible have non-linear, very steep changes in phenomena over a relatively small range. On contrary, transport processes more influenced spatial temperature, momentum, pressure gradients well density, porosity, composition materials. Consequently, emergent phenomena, emission rates or dynamic air concentrations, result complex temperature-dependent relationships that require empirical approach. Indoor environmental conditions further thermal comfort needs occupants. Not only do occupants create serve maintain their core which usually accomplished wearing appropriate clothing, but also surroundings must adapted so they feel comfortable. This includes interaction living space with ambient environment, vary greatly region season. Design houses, apartments, commercial buildings, schools generally utility driven, requiring energy balance, sometimes considering ventilation rarely including impact on contaminant levels. In our article, we start review variables discuss influence typical processes. Then, describe heat balance people environment. An extensive literature study devoted release pollutants from materials various interior compartments aspects chemistry. Finally, assess need consider holistically regard expected global emergencies climate change.

Language: Английский

---

Environmental Stability of Enveloped Viruses Is Impacted by Initial Volume and Evaporation Kinetics of Droplets

mBio, Journal Year: 2023, Volume and Issue: 14(2)

Published: April 10, 2023

During the COVID-19 pandemic, policy decisions were being driven by virus stability experiments with SARS-CoV-2 in different droplet volumes under various humidity conditions. Our study, first of its kind, provides a model for decay multiple enveloped RNA viruses cell culture medium deposited 50-, 5-, and 1-μL droplets at 40%, 65%, 85% RH over time.

Language: Английский

---

Hot‐Pressing Metal Covalent Organic Frameworks as Personal Protection Films

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(13)

Published: Dec. 21, 2023

Abstract Effective personal protection is crucial for controlling infectious disease spread. However, commonly used protective materials such as disposable masks lack antibacterial/antiviral function and may lead to cross infection. Herein, a polyethylene glycol‐assisted solvent‐free strategy proposed rapidly synthesize series of the donor–acceptor metal‐covalent organic frameworks (MCOFs) (i.e., GZHMU‐2, JNM‐1, JNM‐2) under air atmosphere henceforth extend it via in situ hot‐pressing process prepare MCOFs based films with photocatalytic disinfect ability. Best them, newly designed GZHMU‐2 has wide absorption spectrum (200 1500 nm) can efficiently produce reactive oxygen species sunlight irradiation, achieving excellent disinfection performance. After film material, obtained GZHMU‐2/NMF effectively kill E. coli (99.99%), S. aureus (99%), H1N1 (92.5%), meanwhile possessing good reusability. Noteworthy, long‐term use GZHMU‐2/NWF‐based mask verified no damage living body by measuring expression mouse blood routine, lung tissue, inflammatory factors at in‐vivo level.

Language: Английский

---

Oxidative Stress Contributes to Bacterial Airborne Loss of Viability

Microbiology Spectrum, Journal Year: 2023, Volume and Issue: 11(2)

Published: March 13, 2023

While the airborne decay of bacterial viability has been observed for decades, an understanding mechanisms driving remained elusive. The transport bacteria is often a key step in their life cycle and as such, characterizing essential toward more complete microbial ecology. Using Controlled Electrodynamic Levitation Extraction Bioaerosols onto Substrate (CELEBS), it was possible to systematically evaluate impact different physicochemical environmental parameters on survival Escherichia coli droplets Luria Bertani broth. Rather than osmotic stress loss, initially considered, oxidative found play role. As evaporate equilibrate with surrounding environment, surface-to-volume ratio increases, which turn increased formation reactive oxygen species droplet. These appear role loss E. coli. IMPORTANCE wide range impacts, from disease transmission cloud formation. By factors that influence stability bacteria, we can better understand these processes. However, while have known several decades undergo gradual viability, not previously identified this process. In work, discovered droplet facilitates within droplet, then gradually damage kill This discovery indicates adaptations help deal may also aid be pathogens. Understanding need survive could eventually lead development novel antimicrobials designed inhibit survival, helping prevent disease.

Language: Английский

---

Review of factors affecting virus inactivation in aerosols and droplets

Journal of The Royal Society Interface, Journal Year: 2024, Volume and Issue: 21(215)

Published: June 1, 2024

The inactivation of viruses in aerosol particles (aerosols) and droplets depends on many factors, but the precise mechanisms are not known. system involves complex physical biochemical interactions. We reviewed literature to establish current knowledge about these identify gaps. identified 168 relevant papers grouped results by following factors: virus type structure, or droplet size, temperature, relative humidity (RH) evaporation, chemical composition droplet, pH atmospheric composition. These factors influence dynamic microenvironment surrounding a virion thus may affect its inactivation. Results indicate that experience biphasic decay as carrier aerosols undergo evaporation equilibrate with air, their final state (liquid, semi-solid solid) RH. Virus stability, RH temperature interrelated, effects multifaceted still completely understood. Studies impact stability have raised new questions require further exploration. frequent practice studying large culture media limit our understanding for transmission, so we encourage use physiologically size future research.

Language: Английский

---