Airborne Causes of Disease

Objectives Occupational exposure to the composite measure vapours, gases, dusts and fumes (VGDF), contribute to the burden of asthma and rhinitis. The objective was to evaluate occupational exposure to VGDF, which is further divided into the components chemicals, organic and inorganic dust in relation to asthma and rhinitis. Methods Previously examined participants from three population-based cohorts in the Obstructive Lung disease In Northern Sweden (OLIN) studies were re-examined during 2002–2004. In total, 4036 participated in a structured interview and answered a questionnaire on occupational exposures. Results Occupational exposure to VGDF increased the risk of asthma, and concomitant asthma and rhinitis. Exposure to chemicals, but not dust, showed a similar pattern. Exposure to chemicals increased the risks (OR, 95% CI) of rhinitis without asthma (1.29, 1.10 to 1.52), asthma without rhinitis (1.42, 1.15 to 1.77) and concomitant asthma and rhinitis (1.60, 1.31 to 1.96) when adjusted for confounders such as age, smoking habits, body mass index and sex. The association between exposure to chemicals and asthma and rhinitis remained independent of exposure to dust and was also so when excluding exposure to isocyanates and welding fumes. The results were similar for women and men, as well as for never-smokers and participants without a history of allergy. Conclusions In this cross-sectional population-based study, occupational exposure to chemicals contributed substantially to the increased risk of asthma and rhinitis observed for occupational exposure to VGDF.

"Large floor fans create a focused blast that pushes air and the virus a long way. A number of studies show you can get infected at a good distance because of those large fans, Tuznik said."

Aug 2020.

SummaryInfluenza A virus, strain WSNH, propagated in bovine, human and chick embryo cell cultures and aerosolized from the cell culture medium, was maximally stable at low relative humidity (RH), minimally stable at mid-range RH, and moderately stable at high RH. Most lots of WSNH virus propagated in embryonated eggs and aerosolized from the allantoic fluid were also least stable at mid-range RH, but two preparations after multiple serial passage in eggs showed equal stability at mid-range and higher RH's. Airborne stability varied from preparation to preparation of virus propagated both in cell culture and embryonated eggs. There was no apparent correlation between airborne stability and protein content of spray fluid above 0.1 mg/ml, but one preparation of lesser protein concentration was extremely unstable at 50 to 80 per cent RH. Polyhydroxy compounds exerted a protective effect on airborne stability.

(2020). COVID-19 and the workplace: Research questions for the aerosol science community. Aerosol Science and Technology: Vol. 54, No. 10, pp. 1117-1123.

BACKGROUND: Environmental living conditions co-sorting with economic status may influence the disease morbidity rate of childhood asthma in ethnic minority urban poor populations. OBJECTIVES: This study was carried out to assess exposure and sensitization to environmental allergens in southeast San Diego children with current asthma-related symptoms and to determine the utility of environmental control measures. METHODS: Children, 9 to 12 years old, with current asthma-related symptoms were identified and enrolled at four school sites.

A review of the scientific literature aimed at providing a better understanding of aerosols and droplets, and their importance in airborne spread of disease. "Even when a virus can be spread through airborne transmission, you are still much more likely to become ill as the result of close contact. If COVID-19 is transmitted similarly to influenza, we can be somewhat reassured by our current practices."

The global pandemic of COVID-19 has been associated with infections and deaths among health-care workers. This Viewpoint of infectious aerosols is intended to inform appropriate infection control measures to protect health-care workers. Studies of cough aerosols and of exhaled breath from patients with various respiratory infections have shown striking similarities in aerosol size distributions, with a predominance of pathogens in small particles (

Knowing the facts about airborne particulates can make you more effective in managing the hazards they present.

The US Centers for Disease Control and Prevention updated guidance on its website to say coronavirus can commonly spread "through respiratory droplets or small particles, such as those in aerosols," which are produced even when a person breathes.

Is the transmission of novel coronavirus disease (COVID-19) weather dependent?. Journal of the Air & Waste Management Association. Accepted .

Introduction This chapter focuses on the acute effects on the lung after exposure to toxic substances. As used in this chapter, acute indicates short-term exposures (minutes to hours), with the ini…

"Dust is by far the most frequent source of environment-based bacteria and fungi along with the allergens and toxins associated with them. Such dust settled on carpets and upholstery may become resuspended" "Biofilms formed in car heaters/air conditioners [11, 12] as well as those in windshield washer reservoirs [13] and other areas of the car may release microbes such as legionellae and possibly environmental or nontuberculous mycobacteria (NTM) as well as airborne opportunistic pathogens. Such pathogens may also come from road dust and water in road puddles [14]." "Risk of influenza spread ranged from 59% to 99.9% for a 90 min trip when air was recirculated." "Potential health benefits of car deodorizers would be greater if they could additionally reduce the levels of airborne allergens, harmful chemicals, and particulates including PM2.5

***"PM is small enough to suspend in the air for long periods of time, which may provide “condensation nuclei” to which virus droplets attach [45]. Many studies have also reported that PM induces both airway epithelial damage and barrier dysfunction, which could result in a temporary immunosuppressive pulmonary microenvironment " "PM2.5 had almost no effect on influenza incidence at the non-flu season" "when PM2.5 was beyond 70 μg/m3, the effect of PM2.5 had an increasing gradient as PM2.5 increased. Such pattern was clearly more substantial in the middle aged groups and tended to be most pronounced for age group 25–59" "virulence of influenza is expected to be stronger near zero than at subfreezing temperatures and a decrease in temperature makes airways more susceptible to the onset of respiratory infections"

{Normal time periods of viability} "This project investigates survival of airborne influenza virus of different sub-types at common room conditions where risk of disease due to microbial transmission could be particularly high, especially at poorly ventilated environments, where viral concentration in the air reaches significant magnitudes. The results obtained for H1N1 and H5N1 strains show close trend with regards to inactivation in the ambient air; rapid inactivation of approximately 60% of microorganisms over the first 30 min with following inactivation at much slower rate over the remaining 60 min of experiment. A different picture was observed for the H3N2 strain, which demonstrated much higher robustness compared to other subtypes; even after 90 min, around 50% of viral particles were still alive."

Influenza A viruses are believed to spread between humans through contact, large respiratory droplets and small particle droplet nuclei (aerosols), but the relative importance of each of these modes of transmission is unclear. Volunteer studies suggest ...

Includes analyses of effects of humidity on transmission

We analyze the possibility of aerosol transmission of the novel coronavirus. Relevant strategies for preventing novel coronavirus pneumonia are established for the medical personnel and general public during their work or daily life. Chinese Journal of Ophthalmology.

At least indoors, where desiccation is the predominant stress, the general reversibility of membrane-phase changes by vapour-phase rehydration when coupled with efficacious microbial enzymatic repair mechanisms under genetic control, virtually ensures the spread of disease by the aerobiological pathway.

In epidemiological studies where the relationship between moisture in the indoor climate, respiratory symptoms and exposure to allergens is investigated it will be necessary to analyze the role of respiratory viruses in relation to respiratory symptoms. Today, the necessary techniques to address the …

The vast majority of studies reviewed here concern hospital and other health facilities where viruses are a well-known cause of occupational and nosocomial infec-tions. Studies on other indoor environments, on the other hand, including homes, non-industrial workplaces and public buildings, are scarce. The lack of regulations, threshold values and standardized detection meth-ods for viruses in indoor environments, make both research and interpretation of results difficult in this field, hampering infection control efforts. Further research will be needed to achieve a better understanding of virus survival in aerosols and on surfaces, and to elucidate the relationship between viruses and indoor environmental characteristics.

HCPs within 1.829 m of patients with influenza could be exposed to infectious doses of influenza virus, primarily in small-particle aerosols. This finding questions the current paradigm of localized droplet transmission during non-aerosol-generating procedures.

The update officially acknowledges growing evidence that under certain conditions, people farther than six feet apart can become infected by tiny droplets and particles that float in the air for minutes and hours, and that they play a role in the pandemic.

There is overwhelming evidence that inhalation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a major transmission route for coronavirus disease 2019 (COVID-19). There is an urgent need to harmonize discussions about modes of virus transmission across disciplines to ensure the most effective control strategies and provide clear and consistent guidance to the public. To do so, we must clarify the terminology to distinguish between aerosols and droplets using a size threshold of 100 μm, not the historical 5 μm ([ 1 ][1]). This size more effectively separates their ...

Most spread the virus to only a few people — or none at all. But a small percentage transmit it with alarming efficiency, studies show.

CDC provides credible COVID-19 health information to the U.S.

Many of the sharpest increases per capita over the past week came in states like Wisconsin, Utah, Iowa and the Dakotas.