Air pollution and COVID-19 mortality and hospitalization: An ecological study in Iran.

Exposure to air pollution can exacerbate the severe COVID-19 conditions, subsequently causing an increase in the death rate. In this study, we investigated the association between long-term exposure to air pollution and risks of COVID-19 hospitalization and mortality in Arak, Iran. Air pollution data was obtained from air quality monitoring stations located in Arak, including particulate matter (PM), nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3) and carbon monoxide (CO). Daily numbers of Covid-19 cases including hospital admissions (hospitalization) and deaths (mortality) were obtained from a national data registry recorded by Arak University of Medical Sciences. A Poisson regression model with natural spline functions was applied to set the effects of air pollution on COVID-19 hospitalization and mortality. The percent change of COVID-19 hospitalization per 10 µg/m3 increase in PM2.5 and PM10 were 8.5% (95% CI 7.6 to 11.5) and 4.8% (95% CI 3 to 6.5), respectively. An increase of 10 µg/m3 in PM2.5 resulting in 5.6% (95% CI: 3.1-8.3%) increase in COVID-19 mortality. The percent change of hospitalization (7.7%, 95% CI 2.2 to 13.3) and mortality (4.5%, 95% CI 0.3 to 9.5) were positively significant per one ppb increment in SO2, while NO2, O3 and CO were inversely associated with hospitalization and mortality. Our findings strongly suggesting that a small increase in long-term exposure to PM2.5, PM10 and SO2 elevating risks of hospitalization and mortality related to COVID-19.

Generation of Human Micro-Doppler Signature Based on Layer-Reduced Deep Convolutional Generative Adversarial Network.

Human activity recognition (HAR) using radar micro-Doppler has attracted the attention of researchers in the last decade. Using radar for human activity recognition has been very practical because of its unique advantages. There are several classifiers for the recognition of these activities, all of which require a rich database to produce fine output. Due to the limitations of providing and building a large database, radar micro-Doppler databases are usually limited in number. In this paper, a new method for the generation of radar micro-Doppler of the human body based on the deep convolutional generating adversarial network (DCGAN) is proposed. To generate the database, the required input is also generated by converting the existing motion database to simulated model-based radar data. The simulation results show the success of this method, even on a small amount of data.

Acoustic analysis of a single-cylinder diesel engine using magnetized biodiesel-diesel fuel blends.

Fuels have important effects on the quality parameters of engines such as noise pollution and vibration. Diesel fuel are used in wide range of applications especially in compression ignition engines. The objective of the present research is evaluation of the noise emitted from a single-cylinder diesel engine using magnetized biodiesel-diesel fuel blends. In general, samples were provided with different percentages of the biodiesel-diesel blends as diesel (100, 95, 90, and 80%) and biodiesel (0, 5, 10, and 20%) by applying magnetic field (0, 5300 and 7000 G) to fuel line known as DxByMz. The measurements were done on a power tiller engine at a 10 cm distance from driver ear with three replications. The statistical approach in time domain and signal processing in frequency domain were applied for data analysis. The results of the variance analysis approved significant differences between the studied fuel blends and magnetic levels at 1% probability level. The highest and lowest average value of sound pressure level was corresponded to D100B0M0 and D80B20M5300, respectively. The results in frequency domain showed that the maximum sound pressure level values were in the frequency range of 31.5-200 Hz for all fuel blends and magnetic levels. The frequencies related to the maximum sound values varied by changing biodiesel percent and magnetic level.

Bovine Allergens in a Ruminant Clinic and Dairy Barns: Exposure Levels, Determinants, and Variability.

Background: Dairy farmers may develop specific sensitization and allergic airway diseases due to bovine allergens. However, dose-response relationships are lacking, and as yet little is known on bovine allergen exposure levels. Objective: To investigate bovine allergen exposure levels in a ruminant clinic and dairy barns, and to assess exposure determinants and variability of exposure. Methods: Samples were collected using active and passive airborne dust measurements in a ruminant clinic and several dairy barns. Bovine allergen levels were determined by sandwich enzyme-linked immunosorbent assay. Linear mixed models were applied to explore the association between bovine allergen exposure levels and potential exposure determinants. Day-to-day within-worker and between-worker exposure variability was determined, as well as how exposure determinants affect exposure variability. Results: Bovine allergens were measureable in all samples. Personal bovine allergen exposure levels in the ruminant clinic ranged from 0.10 to 24.8 µg/m3, geometric mean (GM) 1.34 µg/m3. Exposure levels varied dependent on job titles. Personal exposure levels in dairy barns ranged from 0.10 to 46.8 µg/m3, GM 1.47 µg/m3. Type of bedding materials in the barns appeared to be a significant determinant of bovine allergen levels. Compost bedding, particularly, increased allergen levels. Milking by robot was the most important determinant explaining between-worker exposure variability, while bedding was important as well. Bovine allergen levels in stationary measurements were somewhat lower than personal measurements (GM ratio 0.47). Bovine allergens could be readily detected in electrostatic dust-fall collector measurements. Conclusion: This study provides insight in bovine allergen exposure levels and their determinants, which is a first step to investigate dose-response relationships between sensitization/allergy associated with exposure to bovine allergen levels in future studies.

Exposure-response analyses for platinum salt-exposed workers and sensitization: A retrospective cohort study among newly exposed workers using routinely collected surveillance data.

BACKGROUND: Chloroplatinate salts are well-known respiratory sensitizing agents leading to work-related sensitization and allergies in the work environment. No quantitative exposure-response relation has been described for chloroplatinate salts. OBJECTIVE: We sought to evaluate the quantitative exposure-response relation between occupational chloroplatinate exposure and sensitization. METHODS: A retrospective cohort study was conducted using routinely collected health surveillance data and chloroplatinate exposure data. Workers who newly entered work between January 1, 2000, and December 31, 2010, were included, and the relation between measured chloroplatinate exposure and sensitization (as determined by skin prick test responses) was analyzed in more than 1000 refinery workers from 5 refineries for whom a total of more than 1700 personal exposure measurements were available. RESULTS: A clear exposure-response relation was observed, most strongly for more recent platinum salt exposure. Average or cumulative exposure over the follow-up period was less strongly associated with sensitization risk. The exposure-response relation was modified by smoking and atopy. CONCLUSIONS: Indications exist that recent exposure explains the risk of platinum salt sensitization most strongly. The precision of the estimate of the exposure-response relation derived from this data set appears superior to previous epidemiologic studies conducted on platinum salt sensitization and as a result, might have possible utility for the development of preventive strategies.

A review of bio-aerosol exposures and associated health effects in veterinary practice.

INTRODUCTION: Occupational exposure to bio-aerosols has been linked to various health effects. This review presents an overview of bio-aerosol exposure levels in veterinary practices, and investigates the possibility of health effects associated with bio-aerosol exposure. METHODS: A systematic literature search was carried out in PubMed. Publications were included if they provided information on bio-aerosol exposure and related health effects through veterinary practice and other professions with similar exposures, occupationally exposed to animals. RESULTS: Few studies in veterinary settings showed that substantial bio-aerosol exposure levels (e.g. endotoxin and ß(1→3)-glucan) were likely occur when handling farm animals and horses. Exposure levels are comparable to those levels observed in farming which have been associated with respiratory health effects. Animal specific allergen exposures have hardly been studied, but showed to be measurable in companion animal clinics and dairy barns. The Findings of the few studies available among veterinary populations, particularly those working with farm animals and horses, are indicative of an elevated risk for developing respiratory symptoms. Studies among pig farmers, exposed to similar environments as veterinarians, strongly confirm that veterinary populations are at an increased risk of developing respiratory diseases in relation to bio-aerosol exposure, in particular endotoxin. Exposure to animal allergens during veterinary practice may cause allergic inflammation, characterized by IgE-mediated reactions to animal allergens. Nonetheless, the occurrence of sensitization or allergy against animal allergens is poorly described, apart from laboratory animal allergy, especially known from exposure to rats and mice. CONCLUSION: Veterinary populations are likely exposed to elevated levels of bio-aerosols such as endotoxins, ß(1→3)-glucans, and some specific animal allergens. Exposures to these agents in animal farmers are associated with allergic and non-allergic respiratory effects, proposing similar health effects in veterinary populations.

The influence of bedding materials on bio-aerosol exposure in dairy barns.

Bio-aerosol is a well-known cause of respiratory diseases. Exposure to bio-aerosols has been reported previously in dairy barns, but little is known about the sources of bio-aerosol. Bedding materials might be a significant source or substrate for bio-aerosol exposure. The aim of this study was to explore bio-aerosol exposure levels and its determinants in dairy barns with various bedding materials. Dust samples were collected at dairy barns using various bedding materials. Samples were analyzed for endotoxin and ß(1 → 3)-glucan contents. Culturable bacteria and fungi were sampled by the Anderson N6 impactor. Exposure models were constructed using linear mixed models. The personal exposure levels to dust, endotoxin, and ß(1 → 3)-glucan differed significantly between the barns utilizing diverse main bedding types (P<0.05), with the highest levels (GM: dust, 1.38 mg/m(3); endotoxin, 895 EU/m(3); ß(1 → 3)-glucan, 7.84 µg/m(3)) in barns with compost bedding vs the lowest in barns with sawdust bedding (GM: dust, 0.51 mg/m(3); endotoxin, 183 EU/m(3); ß(1 → 3)-glucan, 1.11 µg/m(3)). The exposure levels were also highly variable, depending on various extra bedding materials applied. Plant materials, particularly straw, utilized for bedding appeared to be a significant source for ß(1 → 3)-glucan. Compost was significantly associated with elevated exposure levels. Between-worker variances of exposure were highly explained by determinants of exposure like type of bedding materials and milking by robot, whereas determinants could explain to lesser extent the within-worker variances. Exposure levels to endotoxin, ß(1 → 3)-glucan, bacteria, and fungi in dairy barns were substantial and differed depending on bedding materials, suggesting bedding material types as a significant predictor of bio-aerosol exposure.

Sensitisation to common allergens and respiratory symptoms in endotoxin exposed workers: a pooled analysis.

OBJECTIVE: To test the hypotheses that current endotoxin exposure is inversely associated with allergic sensitisation and positively associated with non-allergic respiratory diseases in four occupationally exposed populations using a standardised analytical approach. METHODS: Data were pooled from four epidemiological studies including 3883 Dutch and Danish employees in veterinary medicine, agriculture and power plants using biofuel. Endotoxin exposure was estimated by quantitative job-exposure matrices specific for the study populations. Dose-response relationships between exposure, IgE-mediated sensitisation to common allergens and self-reported health symptoms were assessed using logistic regression and generalised additive modelling. Adjustments were made for study, age, sex, atopic predisposition, smoking habit and farm childhood. Heterogeneity was assessed by analysis stratified by study. RESULTS: Current endotoxin exposure was dose-dependently associated with a reduced prevalence of allergic sensitisation (ORs of 0.92, 0.81 and 0.66 for low mediate, high mediate and high exposure) and hay fever (ORs of 1.16, 0.81 and 0.58). Endotoxin exposure was a risk factor for organic dust toxic syndrome, and levels above 100 EU/m(3) significantly increased the risk of chronic bronchitis (p<0.0001). Stratification by farm childhood showed no effect modification except for allergic sensitisation. Only among workers without a farm childhood, endotoxin exposure was inversely associated with allergic sensitisation. Heterogeneity was primarily present for biofuel workers. CONCLUSIONS: Occupational endotoxin exposure has a protective effect on allergic sensitisation and hay fever but increases the risk for organic dust toxic syndrome and chronic bronchitis. Endotoxin's protective effects are most clearly observed among agricultural workers.

Allergy among veterinary medicine students in The Netherlands.

BACKGROUND: Veterinary medicine students who practice with animals are potentially exposed to many occupational agents, yet sensitisation and allergic symptoms among this group have not been studied extensively. OBJECTIVE: The objective of this study was to estimate the prevalence of sensitisation and allergic symptoms in veterinary medicine students in association with study specialisation over time. METHODS: A questionnaire-based cross-sectional study was conducted. Blood was collected and tested for total and specific serum IgE for 16 different common and study-specific allergens using enzyme immunoassay. RESULTS: New development of self-reported allergic symptoms to various allergens occurred in 8.7%, of which 44% was deducted against animals. Handling farm animals was strongly associated with self-reported allergies to various allergens (OR=6.9, 95% CI 1.9 to 25) and animal allergens (OR=12, 95% CI 1.4 to 103). Sensitisation to at least one allergen occurred in 33.1%. Sensitisation prevalence tended to be elevated in later years of the equine study program. In contrast to self-reported allergies, the prevalence of sensitisation to any allergen decreased with prolonged study duration for those specialising in farm animal health (years 3-5: OR=0.5, 95% CI 0.3 to 1.1; year 6: OR=0.2, 95% CI 0.1 to 0.5). This was independent of whether people were raised on a farm, which is in itself a protective factor for allergy and sensitisation. CONCLUSION: This study provides evidence of an elevated prevalence of allergic symptoms with increasing years of veterinary study, suggesting that contact with animals, more specifically contact to farm animals, is a risk factor for the development of symptoms.

Endotoxin and ß-(1 → 3)-glucan exposure in poultry and ruminant clinics.

BACKGROUND: Exposure to organic dust is a well-known hazard for farm animal workers leading to respiratory diseases. Organic dust exposure has not been adequately evaluated in environmental settings in relation to veterinarians. OBJECTIVE: To investigate inhalable dust, endotoxin, and ß-(1 → 3)-glucan exposure among caretakers, veterinarians, and veterinary students. Task-based determinants of exposure were studied. METHODS: This study investigated the exposure during veterinary education in the ruminant and poultry clinics. Dust measurements were performed using the conical inhalable samplers (CIS). Endotoxin and ß-(1 → 3)-glucan were determined by the kinetic limulus amebocyte lysate (LAL) assay and inhibition enzyme immunoassay (EIA), respectively. Determinants of exposure were identified by multiple linear regression analysis. RESULTS: Personal exposure levels of dust, endotoxin, and ß-(1 → 3)-glucan were higher for poultry [geometric mean (GM): dust, 1.32 mg m(-3) (below the lower limit of detection (

Allergen and endotoxin exposure in a companion animal hospital.

BACKGROUND: Exposure to allergens, both in general and occupational environments, is known to result in sensitisation and exacerbation of allergic diseases, while endotoxin exposure might protect against allergic diseases. This may be important for veterinarians and co-workers. However, exposure levels are mostly unknown. OBJECTIVE: We investigated the allergen and endotoxin exposure levels of veterinary medicine students and workers in a companion animal hospital. METHODS: Airborne and surface dust was collected using various sampling methods at different locations. Allergen levels in extracts were measured with sandwich ELISAs and/or the multiplex array for indoor allergens (MARIA). Endotoxin was determined by limulus amebocyte lysate (LAL) assay. RESULTS: Fel d 1 (Felis domesticus), Can f 1 (Canus familiaris) and endotoxin were detected in all except stationary samples. The geometric mean (GM) level of personal inhalable dust samples for Fel d 1 was 0.3 ng/m(3) (range: below lower limit of detection (

Exposure to inhalable dust, endotoxins, beta(1->3)-glucans, and airborne microorganisms in horse stables.

OBJECTIVES: Workers in horse stables are likely exposed to high levels of organic dust. Organic dusts play a role in increased risk of inflammatory reactions and are associated with respiratory diseases. The aim of this study was to investigate dust, endotoxin, beta(1-->3)-glucan, and culturable microorganisms exposure levels in horse stables. METHODS: Ambient (n = 38) and personal (n = 42) inhalable dust samples were collected using PAS-6 sampling heads. As a special measurement, we included sampling near the horses' heads. Samples were analyzed for endotoxin and beta(1-->3)-glucan by Limulus amebocyte lysate assay and an inhibition enzyme immunoassay, respectively. Culturable bacteria and fungi were collected with an Anderson impactor. RESULTS: Geometric means (GMs) of personal exposure to dust, endotoxin, and beta(1-->3)-glucan were 1.4 mg m(-3) (range 0.2-9.5), 608 EU m(-3) (20-9846), and 9.5 microg m(-3) (0.4-631 microg m(-3)), respectively. Exposure levels in the morning shift were higher compared to other shifts. The GMs (ranges) of culturable bacteria and fungi were 3.1 x 10(3) colony-forming unit (CFU) m(-3) (6.7 x 10 to 1.9 x 10(4)) and 1.9 x 10(3) CFU m(-3) (7.4 x 10 to 2.4 x 10(4)), respectively. Variance components for endotoxin and beta(1-->3)-glucan were considerably higher than for dust. Based on dummy variable in a mixed regression analysis, the predominant task explaining exposure levels of dust, endotoxin, and beta(1-->3)-glucan was sweeping the floor. For beta(1-->3)-glucan, feeding the horse was also an important determinant. CONCLUSION: Dust, endotoxin, and beta(1-->3)-glucan exposure are considerable in horse stables. Bacterial and fungal exposure levels were moderate. Endotoxin exposures were above the Dutch proposed standard limits, suggesting workers in horse stables to be at risk of adverse health effects.