Ambient fungal spores within the atmosphere can contribute to a range of negative human, animal and plant health conditions and diseases. However, trends in fungal spore seasonality, species prevalence, and geographical origin have been significantly understudied in Ireland. Previously unpublished data from the late 1970s have recently been collected and analysed to establish historical fungal spore trends/characteristics for Dublin. Historical spore concentrations were largely dominated by Alternaria, Ascospores, Basidiospores, Botrytis, Cladosporium, Erysiphe and Rusts. The main fungal spore season for Dublin commenced in April with the fructification of Scopulariopsis and Ganoderma. However, the vast majority of other spore types did not reach peak spore release until late summer. The correlation between ambient spore concentration, and meteorological parameters was examined using Multivariable Regression Tree (MRT) analysis. The notable correlations found for fungal spore concentrations tended to involve temperature-based parameters. The use of a non-parametric wind regression was also employed to determine the potential geographical origin of ambient fungal spores. The impact of wind direction, and high windspeed on fungal spores was established, ultimately highlighting the importance of studying and monitoring fungal spores within Ireland, rather than attempting to rely on data from other regions, as most fungal spores collected in Dublin appeared to originate from within the island.

Throughout the COVID-19 pandemic, meat processing plants have been vulnerable to outbreaks of SARS-CoV-2 infection. Transmission of the virus is difficult to control in these settings because of a combination of factors including environmental conditions and the specific nature of the work. This paper describes a retrospective outbreak investigation in a meat processing plant, a description of the measures taken to prevent or contain further outbreaks, and insights on how those with specific knowledge of the working environment of these plants can collaborate with public health authorities to ensure optimal outbreak control. The plant experienced 111 confirmed positive asymptomatic cases in total with an estimated attack rate of 38% during a five-week period. 4 weeks after the first case, mass screening of all workers was conducted by the public health authorities. Thirty-two workers tested positive, of which 16 (50%) worked in one particular area of the plant, the boning hall (n = 60). The research team prepared and carried out semi-structured interviews with the plant personnel who were charged with COVID control within the plant. They carried out assessments of operational risk factors and also undertook air quality monitoring in the boning hall and abattoir. The air quality measurements in the boning hall showed a gradual build-up of carbon dioxide and aerosol particles over the course of a work shift, confirming that this poorly ventilated area of the plant had an environment that was highly favorable for aerosol transmission of SARS-CoV-2. Assessment of operational conditions incorporated visual surveys of the plant during the working day. Prior to and during the first 2 weeks of the outbreak, multiple measures were introduced into the plant by management, including physical distancing, provision of educational material to workers, visitor restrictions, and environmental monitoring. After the implementation of these measures and their progressive refinement by plant management, the factory had no further linked cases (clusters) or outbreaks for the following 198 days. The tailored approach to risk mitigation adopted in this meat processing plant shows that generic risk mitigation measures, as recommended by public health authorities, can be successfully adapted and optimized by designated plant emergency response teams.

BACKGROUND:Several medical procedures involving the respiratory tract are considered as 'aerosol-generating procedures'. Aerosols from these procedures may be inhaled by bystanders, and there are consequent concerns regarding the transmission of infection or, specific to nebulized therapy, secondary drug exposure.AIM:To assess the efficacy of a proprietary high-efficiency-particulate-air-filtering extractor tent on reducing the aerosol dispersal of nebulized bronchodilator drugs.METHODS:The study was conducted in an unoccupied outpatient room at St. James's Hospital, Dublin, Ireland. A novel real-time, fluorescent particle counter, the Wideband Integrated Bioaerosol Sensor (WIBS), monitored room air continuously for 3 h. Baseline airborne particle count and count during nebulization of bronchodilator drug solutions were recorded.FINDINGS:Nebulization within the tent prevented any increase over background level. Nebulization directly into room air resulted in mean fluorescent particle counts of 4.75 x 105/m3 and 4.21 x 105/m3 for Ventolin and Ipramol, respectively, representing more than 400-fold increases over mean background level. More than 99.3% of drug particles were <2 μm in diameter and therefore small enough to enter the lower respiratory tract.CONCLUSION:The extractor tent was completely effective for the prevention of airborne spread of drug particles of respirable size from nebulized therapy. This suggests that extractor tents of this type would be efficacious for the prevention of airborne infection from aerosol-generating procedures during the COVID-19 pandemic.

This study analysed the effectiveness of plasma treatment on airborne bacteria and surface counts during a 14-day intervention within a four-bedded bay in an adult respiratory ward at Cork University Hospital, Ireland. One-hundred-litre air samples were collected twice daily every weekday for 4 weeks, with settle plates and surface swabs. The plasma treatment did not have an effect on airborne bacteria and fungi that was detectable by culture. However, the possibility that culture-based sampling may be insufficiently sensitive to detect an effect, or that the duration of the study was insufficient for plasma treatment to affect a complex environment, cannot be excluded.

Abstract Public awareness of the rising importance of allergies and other respiratory diseases has led to increased scientific effort to accurately and rapidly monitor and predict pollen, fungal spores and other bioaerosols in our atmosphere. An important driving force for the increased social and scientific concern is the realisation that climate change will increasingly have an impact on worldwide bioaerosol distributions and subsequent human health. In this review we examine new developments in monitoring of atmospheric pollen as well as observation and source-orientated modelling techniques. The results of a Scopus® search for scientific publications conducted with the terms ‘Pollen allergy’ and ‘Pollen forecast’ included in the title, abstract or keywords show that the number of such articles published has increased year on year. The 12 most important allergenic pollen taxa in Europe as defined by COST Action ES0603 were ranked in terms of the most ‘popular’ for model-based forecasting and for forecasting method used. Betula, Poaceae and Ambrosia are the most forecast taxa. Traditional regression and phenological models (including temperature sum and chilling models) are the most used modelling methods, but it is notable that there are a large number of new modelling techniques being explored. In particular, it appears that Machine Learning techniques have become more popular and led to better results than more traditional observation-orientated models such as regression and time-series analyses.

Nebulisers convert liquids into a fine mist of suspended particles that are inhalable into the respiratory tract. They are used to deliver drug therapy by the respiratory route, for example bronchodilators, or to aid production of diagnostic sputum samples (sputum induction). On continuous monitoring of biological airborne particles in a respiratory ward over 4 weeks using a biological particle detector (WIBS) the majority of detected particles were attributable to nebuliser therapy. Tents with extractor/filter devices are indicated for infection control purposes in collection of induced sputum from patients with suspected tuberculosis. We tested the efficacy of an extractor tent (Demistifier 2000, Peace Medical) on reducing detectable aerosols from nebulised bronchodilator drugs by continuously monitoring a room outside a tent containing a nebuliser. The mean fluorescent particle count per m3 was 0.63 and 0.31 (equivalent to background levels pre-nebuliser) for nebulised Ventolin and Ipramol, respectively, when they were nebulised within the tent. Removing the tent and nebulising directly into room air resulted in a 2.56×104 and 4.64×104-fold increase in particle concentrations for Ventolin and Ipramol, respectively, over background levels. WIBS monitoring therefore showed 100 % efficacy of the tent in restricting spread of nebulised drug particles. Extractor tents can prevent spread of drug particles from nebulised therapy. The implications of this will be discussed.

Background: The monitoring of bioaerosol concentrations in the air is a relevant endeavor due to potential health risks associated with exposure to such particles and in the understanding of their role in climate. In this context, the atmospheric concentrations of bacteria were measured from January 2018 to May 2020 at Saclay, France. The aim of the study was to understand the seasonality, the daily variability, and to identify the geographical origin of airborne bacteria. Methods: 880 samples were collected daily on polycarbonate filters, extracted with purified water, and analyzed using the cultivable method and flow cytometry. A source receptor model was used to identify the origin of bacteria. Results: A tri-modal seasonality was identified with the highest concentrations early in spring and over the summer season with the lowest during the winter season. Extreme changes occurred daily due to rapid changes in meteorological conditions and shifts from clean air masses to polluted ones. Conclusion: Our work points toward bacterial concentrations originating from specific seasonal-geographical ecosystems. During pollution events, bacteria appear to rise from dense urban areas or are transported long distances from their sources. This key finding should drive future actions to better control the dispersion of potential pathogens in the air, like persistent microorganisms originating from contaminated areas.

Flushing toilets generate visible droplets from turbulent flow, but also produce numerous smaller airborne droplets (∼micrometres in size) through atomisation. Flushing may aerosolise pathogens from stool or urine, spreading disease. This study continuously monitored aerosols in a shared office lavatory over a week using a biological particle detector, the Wideband Integrated Bioaerosol Sensor (WIBS). This instrument monitors individual particle sizes and numbers and identifies fluorescent particles likely to be droplets containing bacteria. The toilet was a standard wash-down design, (Armitage Shanks), with a lid. No statistically significant variation between fluorescent particle counts was found between periods prior to flushing. Fluorescent particle numbers and intensity increased with toilet flushing, remaining above background for 5 minutes post-flushing on average. Placing the toilet lid down significantly (P<0.001) reduced total and fluorescent particle counts during and after flushing by 30-50%. Lid usage significantly increased (P<0.001) particle diameter from 1.5 μm to 2.1 μm and increased particle fluorescence intensity (P<0.001) during flushing and after flushing, intensity remaining above background for 16 minutes. This suggests standard lid usage reduces but does not eliminate flush-related bioaerosols. Lid-use changes their characteristics and apparently prolongs their residence time in room air. The aerosol change could represent particle agglomeration by a pressure-related Kelvin effect or particle re-aerosolisation from different surfaces in the toilet rather than exclusively originating from droplet generation. Previous studies reporting the effect of toilet lids have found that they prevent the spread of visible droplets on flushing, however the effect on smaller particles is less clear cut.

Airborne fungal spores (AFS) represent the major fraction of primary biological aerosol particles (PBAPs), and they are studied worldwide largely due to their important role within the Earth system. They have an impact on climate and human health, and they contribute to the propagation of diseases. As their presence in the air depends largely on studied ecosystems, a spore trap was used to monitor their atmospheric concentrations from 2014 to December 2018 in Saclay, a suburban area in the megacity of Paris. The main objective of this work was: (1) to understand the atmospheric variability of AFS in relation to different variables such as meteorological factors, agricultural practice, and (2) to identify their geographical origin by using a source receptor model. During our period of observation, 30 taxa have been identified under a light microscope. In order of importance, Ascospores, Cladosporium, Basidiospores, Tilletiopsis, Alternaria were found to be the most abundant types respectively (50.8%, 33.6%, 7.6%, 1.8%, and 1.3%) accounting for 95% of the atmospheric concentrations. We observed a general decrease associated with a strong interannual variability. A bimodal seasonal cycle was identified with a first maximum in July and a second in October. The main parameters driving the atmospheric concentration are temperature and precipitation. The daily variability is strongly activated by successive periods of hot weather and rainfall, multiplying the concentration by a factor of 1000 in less than 12 hours. Results from the source receptor model ZeFir point out unambiguous different origins of AFS due to specific sources impacting the observation site. Our study also indicated that a hydrological stress has a direct effect on the daily concentrations. This last point should be taken into account for every stressed ecosystem studied in a global warming context. This is particularly important for Mediterranean areas where water is a key control of the growth and dispersion of fungal spores.

Conventional microbial sampling of air in hospitals is usually carried out using settle plates or impaction air samples. This provides little information about intermittent contamination events and is unhelpful for source attribution. Direct continuous bioaerosol sampling is an established technology used to characterise ambient external air. Portable instruments such as the Wideband Integrated Bioaerosol Sensor (WIBS) combine laser particle size and shape detection with signals of biological origin (fluorescence from amino acids and NAD(P)H) characteristic of viable bioaerosols. Monitoring is continuous for weeks at a time and data collected remotely over the internet. We present evidence of the utility of WIBS analysis in characterising air in hospitals in three different environments: operating theatres (plenum ventilated and ultraclean), a respiratory ward, and a specialist cystic fibrosis outpatients. The airborne particle profile was quantitatively and qualitatively different in each environment. Plumes of biologically-relevant airborne particles were detected and source investigation of failing conventional counts in an operating theatre aided by the continuous record. Nebulised drugs contributed a detectable effect on airborne particles which lasted for several hours on the ward despite air changes. A significant effect of plasma air treatment on airborne particles in the ward was detected by WIBS and not conventional cultures. Continuous monitoring may in future allow objective standard setting for airborne particles in different hospital environments and facilitate rapid detection of airborne infection risks.

A wideband integrated bioaerosol sensor (WIBS-4) was deployed in Haulbowline Island, Cork Harbour, to detect fluorescence particles in real time during July and September 2011. A scanning mobility particle sizer (SMPS) was also installed providing sizing analysis of the particles over the 10–450 nm range. During the campaign, multiple fog formation events occurred; they coincided with dramatic increases in the recorded fluorescent particle counts. The WIBS sizing and fluorescence intensity profiles indicated that the origin of the signals was potentially non-biological in nature (i.e. PBAPs, primary biological aerosol particles). Furthermore, the data did not support the presence of known fluorescing chemical particles like SOA (secondary organic aerosol). Complementary laboratory studies showed that the field results could potentially be explained by the adsorption of molecular iodine onto water droplets to form I2 ⋅ (H2O)x complexes. The release of iodine into the coastal atmosphere from exposed kelp at low tides has been known for many years. This process leads to the production of small IxOy particles, which can act as cloud condensation nuclei (CCN). While the process of molecular iodine release from coastal kelp sources, subsequent particle formation, and the observations of sea mists and fogs have been studied in detail, this study provides a potential link between the three phenomena. Of mechanistic interest is the fact that molecular iodine included into (rather than on) water droplets does not appear to fluoresce as measured using WIBS instrumentation. The study indicates a previously unsuspected stabilizing transport mechanism for iodine in the marine environment. Hence the stabilization of the molecular form would allow its more extensive distribution throughout the troposphere before eventual photolysis.

Department of Communications, Climate Action and Environment (EPA Research Programme 2014–2020); Irish Research Council (Research Studentship)

Primary Biological Aerosol Particles (PBAP) are an omnipresent component of atmospheric aerosols. PBAP consist of an assortment of entities of biological origin with pollen, bacteria and fungal spores among the most studied in the atmosphere. PBAP has long been associated with health implications such as hayfever, COPD, asthma and aspergillious to name but a few. Allied to this PBAP also have the potential to act as cloud condensation nuclei or ice nuclei in cloud formation and thus have climatic inferences. Hence the need to study the concentration and composition of such particles is of interest to all. However within Ireland little has been done with regard to the amounts or identity of biological particles in the literature. This work represents first sustained monitoring of PBAP in decades. The work presented here has looked at both traditional (based on impactation on a filter and subsequent optical analysis) and newer real-time methodologies (utilizing fluorescence) for the monitoring of pollen and fungal spores at a site located in the heart of Dublin, Ireland. The sampling campaign utilized a Hirst volumetric trap, WIBS-4 and Japanese pollen counter to develop a seasonal cycle for the prevalence of pollen and fungal species in the Irish atmosphere. The real-time and traditional instrumentation were also compared and contrasted to evaluate weather real-time instrumentation was comparable to the currently most used technique (Hirst trap) around the world. The traditional data in tandem with meteorological parameters, phenological data and source mapping were then used to formulate an Irish specific pollen model using several methods (multiple regression, random forest and neural networks).The incorporation of real-time pollen data into the models was then attempted with hope of increasing the accuracy, precision and timeliness of the forecasts.

An air measurement campaign was carried out at a green-waste composting site in the South of Ireland during Spring 2016. The aim was to quantify and identify the levels of Primary Biological Aerosol Particles (PBAP) that were present using the traditional off-line, impaction/optical microscopy method alongside an on-line, spectroscopic approach termed WIBS (Wideband Integrated Bioaerosol Sensor), which can provide number concentrations, sizes and "shapes" of airborne PBAP in real-time by use of Light Induced Fluorescence (LIF). The results from the two techniques were compared in order to validate the use of the spectroscopic method for determining the releases of the wide-range of PBAP present there as a function of site activity and meteorological conditions. The seven-day monitoring period undertaken was much longer than any real-time studies that have been previously performed and allowed due comparison between weekday (working) activities at the site and weekend (closed) releases. The time-span also allowed relationships between site activities like turning, agitation or waste delivery and the WIBS data to be determined in a quantitative manner. This information cannot be obtained with the Andersen Sampling methods generally employed at green-waste management sites. Furthermore, few specific bioaerosol types other than Aspergillus fumigatus, are identified using the traditional protocols employed for site licensing purposes. Here though the co-location of WIBS with the impaction instrument made it possible to identify the real-time release behaviour of a specific plant pathogenic spore, Ustilago maydis, present after green-waste deliveries were made by a local distillery.

Airborne Particulate Matter (PM) is ubiquitous in both indoor and outdoor environments. Its adverse effect on human health is well known and is associated with both size and composition of particles. PM is a complex and heterogenous mixture, including a range of both toxic and non-toxic chemical compounds. These materials can penetrate in the human respiratory tract with the possibility to cause respiratory and heart related illnesses. Small particulate pollution has health impacts even at very low concentrations – no threshold has been identified below which no damage to health is observed. WHO estimates that in 2012 around 1 in 8 deaths were attributed to exposure to air pollution, making it the number one environmental risk factor for ill health. Particulate matter (PM) constitute a principal component of residential indoor air pollution and have been linked with both acute effects, such as irritation in the skin, eyes, nose and throat and upper airways, and chronic health effects including asthma and cardiac disease. It is also of concern in many workplace environments across a wide range of industries and sectors. Wood dust, especially hardwood dust, has been known to cause health problems and cancers in workers. Aerosols from cleaning spray products pose a threat to cleaning workers. In the ceramic sector workers can be exposed to a wide variety of powdered materials with different characteristics and chemical compositions during the manufacturing cycle (handling, materials preparation, bag filling, tiles production or cleaning processes, among others). Cooking aerosols are emitted in high concentrations from processes like frying and charbroiling, exposing kitchen and restaurant workers to high levels of airborne organic aerosols. Nanoparticles is a relatively new and little understood threat to both manufacturing and laboratory workers, and it is not known how many escape to the wider environment. Any workshop environment may contain high levels of particles in the indoor air, as will construction environments, where workers may potentially be exposed to a range of materials, including asbestos particles. Even office workers occupying near-road premises can experience high levels of toxic particles from vehicle emissions. Furthermore, bioaerosols are a class of atmospheric particles that include bacteria, viruses, pollen and fungal spores, algae, plant debris, proteins, etc. This class of particles can also have an impact on public health, as they have been associated with infectious diseases, allergies, acute toxic effects and even cancer.

The study of the origin and dispersion processes associated with airborne pollen grains are important to understand due to their impacts on health. In this context, a Hirst-type spore trap was utilized over the period 2015–2018 to monitor ambient pollen grains at Saclay, France, a receptor site influenced by both clean air masses originating from the Atlantic Ocean and polluted air masses under anticyclonic conditions. The objective of this work was to use ZeFir (a user-friendly, software tool recently-developed to investigate the geographical origin and point sources of atmospheric pollution) as a method to analyse total and allergenic airborne pollen grain concentrations. Strong interannual variability was exhibited for the total pollen grains concentrations and it was determined that this was mainly driven by Betulaceae pollen, with a general increasing trend displayed. The start of the pollen season was seen to be triggered by particular synoptic conditions after a period of dormancy and two maximums were displayed, one in April and a second in June. Results from the ZeFir tool, fed with on-site hourly meteorological and pollen measurements, demonstrate that the dominant pollen grains inputs to Saclay are favoured by non-prevailing winds originating from East and North in association with dry air, moderate winds, mild temperature and enhanced insolation.

Primary biological aerosol particles (PBAP) encompass many particle types that are derived from several biological kingdoms. These aerosol particles can be composed of both whole living units such as pollen, bacteria, and fungi, as well as from mechanically formed particles, such as plant debris. They constitute a significant proportion of the overall atmospheric particle load and have been linked with adverse health issues and climatic effects on the environment. Traditional methods for their analysis have focused on the direct capture of PBAP before subsequent laboratory analysis. These analysis types have generally relied on direct optical microscopy or incubation on agar plates, followed by time-consuming microbiological investigation. In an effort to address some of these deficits, real-time fluorescence monitors have come to prominence in the analysis of PBAP. These instruments offer significant advantages over traditional methods, including the measurement of concentrations, as well as the potential to simultaneously identify individual analyte particles in real-time. Due to the automated nature of these measurements, large data sets can be collected and analyzed with relative ease. This review seeks to highlight and discuss the extensive literature pertaining to the most commonly used commercially available real-time fluorescence monitors (WIBS, UV-APS and BioScout). It discusses the instruments operating principles, their limitations and advantages, and the various environments in which they have been deployed. The review provides a detailed examination of the ambient fluorescent aerosol particle concentration profiles that are obtained by these studies, along with the various strategies adopted by researchers to analyze the substantial data sets the instruments generate. Finally, a brief reflection is presented on the role that future instrumentation may provide in revolutionizing this area of atmospheric research.