Risk Assessment Evaluation Research Articles

Acute toxicity of nanoplastics on Daphnia and Gammarus neonates: Effects of surface charge, heteroaggregation, and water properties

Despite progress in evaluation of risk assessment, knowledge gaps largely exist understanding the toxicity of nanoplastics in aquatic systems considering nanoplastics surface properties, environmental media characteristics and species ecological traits. In this study, amidine - functionalized polystyrene nanoparticles (PS-NPLs) of 20, 40, 60 and 100 nm are considered using Geneva lake water and mineral water to investigate the behavior and effects in neonate organisms of the plankton Daphnia magna and the benthos Gammarus fossarum. Key parameters including ζ-potential, z-average diameter, conductivity, polydispersity index, pH, EC50 were investigated. The results showed that the toxicity of PS-NPLs exhibited a dose-response relationship, size- and exposure condition-dependent trend. The smaller size PS-NPLs (20 and 40 nm) induced higher adverse effects than PS-NPLs of 60 and 100 nm in both water conditions and crustacean species. Moreover, PS-NPLs were found more toxic in the mineral water compared to lake water. Principal component analysis evidenced that the surface charge and aggregation behavior are the most influential toxicity of PS-NPLs factor for D. magna and Gammarus fossarum, respectively. These results highlight the relationship between PS-NPLs intrinsic properties, their transformation behavior, water properties and species-specificity in the evaluation of PS-NPLs biological effects on crustacean neonates in natural aquatic environments.

Association of Genetic Predisposition and Physical Activity With Risk of Gestational Diabetes in Nulliparous Women

Polygenic risk scores (PRS) for type 2 diabetes (T2D) can improve risk prediction for gestational diabetes (GD), yet the strength of the association between genetic and lifestyle risk factors has not been quantified. To assess the association of PRS and physical activity in existing GD risk models and identify patient subgroups who may receive the most benefits from a PRS or physical activity intervention. The Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be cohort was established to study individuals without previous pregnancy lasting at least 20 weeks (nulliparous) and to elucidate factors associated with adverse pregnancy outcomes. A subcohort of 3533 participants with European ancestry was used for risk assessment and performance evaluation. Participants were enrolled from October 5, 2010, to December 3, 2013, and underwent genotyping between February 19, 2019, and February 28, 2020. Data were analyzed from September 15, 2020, to November 10, 2021. Self-reported total physical activity in early pregnancy was quantified as metabolic equivalents of task (METs). Polygenic risk scores were calculated for T2D using contributions of 84 single nucleotide variants, weighted by their association in the Diabetes Genetics Replication and Meta-analysis Consortium data. Estimation of the development of GD from clinical, genetic, and environmental variables collected in early pregnancy, assessed using measures of model discrimination. Odds ratios and positive likelihood ratios were used to evaluate the association of PRS and physical activity with GD risk. A total of 3533 women were included in this analysis (mean [SD] age, 28.6 [4.9] years). In high-risk population subgroups (body mass index ≥25 or aged ≥35 years), individuals with high PRS (top 25th percentile) or low activity levels (METs <450) had increased odds of a GD diagnosis of 25% to 75%. Compared with the general population, participants with both high PRS and low activity levels had higher odds of a GD diagnosis (odds ratio, 3.4 [95% CI, 2.3-5.3]), whereas participants with low PRS and high METs had significantly reduced risk of a GD diagnosis (odds ratio, 0.5 [95% CI, 0.3-0.9]; P = .01). In this cohort study, the addition of PRS was associated with the stratified risk of GD diagnosis among high-risk patient subgroups, suggesting the benefits of targeted PRS ascertainment to encourage early intervention.

The amphipod Parhyale hawaiensis as a promising model in ecotoxicology

Near-shore marine/estuarine environments play an important role in the functioning of the marine ecosystem and are extremely vulnerable to the presence of chemical pollution. The ability to investigate the effects of pollution is limited by a lack of model organisms for which sufficient ecotoxicological information is available, and this is particularly true for tropical regions. The circumtropical marine amphipod Parhyale hawaiensis has become an important model organism in various disciplines, and here we summarize the scientific literature regarding the emergence of this model within ecotoxicology. P. hawaiensis is easily cultured in the laboratory and standardized ecotoxicity protocols have been developed and refined (e.g., miniaturized), and effects of toxicants on acute toxicity (Cd, Cu, Zn, Ag, ammonia, dyes, pesticides, environmental samples), genotoxicity as comet assay/micronuclei, and gene expression (Ag ion and Ag nanoparticles) and regeneration (pesticides) have been published. Methods for determination of internal concentrations of metals (Cu and Ag) and organic substances (synthetic dye) in hemolymph were successfully developed providing sources for the establishment of toxicokinetics models in aquatic amphipods. Protocols to evaluate reproduction and growth, for testing immune responses and DNA damage in germ cells are under way. The sensitivity of P. hawaiensis, measured as 50% lethal concentration (LC50), is in the same range as other amphipods. The combination of feasibility to culture P. hawaiensis in laboratory, the recent protocols for ecotoxicity evaluation and the rapidly expanding knowledge on its biology make it especially attractive as a model organism and promising tool for risk assessment evaluations in tropical environments.

Interlaboratory comparison of serum lipoprotein(a) analytical results across clinical assays – A step towards standardization

Background and Aims : Lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular disease (CVD). The 2019 EAS and 2018 ACC/AHA clinical guidelines recommend measuring Lp(a); however, Lp(a) measurement variability across different assays persists. Standardization of Lp(a) clinical assays will minimize inter-assay variability, which will improve patient CVD risk assessment and future evaluations of Lp(a) therapeutic efficacy. Most individuals are heterozygous and have 2 Lp(a) sizes circulating.

A numerical approach to evaluate temperature-dependent peridynamics damage model for destructive atmospheric entry of spacecraft

AbstractThe evaluation of the on-ground casualty risk assessments due to a controlled or uncontrolled re-entry is highly sensitive to the accurate prediction of fragmentation events during an atmospheric re-entry. The main objective of this study is an investigation into the use of peridynamics (PD) to improve the analysis of fragmentation during atmospheric re-entry with respect to currently adopted semi-empirical approaches. The high temperatures characterising such scenarios may substantially impact fragmentation, which requires appropriate modelling of the damage process within the PD method. The damage models in PD require experimentally determined fracture mechanical properties that are unavailable as a function of temperature. This work proposes a numerical methodology to estimate the PD damage parameters changes with temperature to enable the study of fragmentation during atmospheric re-entry. Initially, tensile-testing simulation experiments are performed in peridynamics to calibrate material parameters for steel and aluminium alloys as a function of temperature. Then, a parametric study is carried out to evaluate the temperature-dependent damage model parameters for the same materials. The applicability of the proposed methodology is showcased using a re-entry test case scenario.

Emergent interactive effects of climate change and contaminants in coastal and ocean ecosystems

The effects of climate change (CC) on contaminants and their potential consequences to marine ecosystem services and human wellbeing are of paramount importance, as they pose overlapping risks. Here, we discuss how the interaction between CC and contaminants leads to poorly constrained impacts that affects the sensitivity of organisms to contamination leading to impaired ecosystem function, services and risk assessment evaluations. Climate drivers, such as ocean warming, ocean deoxygenation, changes in circulation, ocean acidification, and extreme events interact with trace metals, organic pollutants, excess nutrients, and radionuclides in a complex manner. Overall, the holistic consideration of the pollutants-climate change nexus has significant knowledge gaps, but will be important in understanding the fate, transport, speciation, bioavailability, toxicity, and inventories of contaminants. Greater focus on these uncertainties would facilitate improved predictions of future changes in the global biogeochemical cycling of contaminants and both human health and marine ecosystems.

Evaluation of Heavy Metal Content and Human Health Risk Assessment of Water Leaf (Talinum triangulare) Grown on Arsenic Spiked Soils

AIM: This study investigated the concentration of heavy metal (Arsenic), taken up by waterleaf plant cultivated in three contaminated soil type namely; sandy, loamy and clay. The health risk associated in exposing the waterleaf plants was accessed from the different soil types at different treatment levels of 40mg/kg (low) and 80mg/kg (high) of arsenic.&#x0D; Methods: Three soil types namely; sandy, loamy and clay were spiked with 40 mg/kg and 80 mg/kg of arsenic. The waterleaf plant was grown on the spiked soil samples for the period of 2, 4, 6 and 8 weeks. Each soil sample was taken before the spiking of the soil to serve as the basal control soil sample. This will determine the content of arsenic in the soil. After the stipulated growth period, the soil sample was collected into a clean sample bottle likewise the waterleaf plant which was harvested, washed, oven dried and ground into a powdered form which was acid digested. The heavy metal content in both the plant and soils were determined by atomic absorption spectroscopy.&#x0D; Results: The results of arsenic concentration in waterleaf from loamy soil at 40 mg/kg were 0.118 mg/kg, 0.189 mg/kg, 0.295 mg/kg, and 0.332 mg/kg at weeks 2, 4, 6, and 8 respectively. At 80 mg/kg, arsenic concentrations in loamy soil were 0.200 mg/kg, 0.388 mg/kg, 0.612 mg/kg and 0.693 mg/kg respectively. For sandy soil, the concentration of arsenic in the waterleaf plant treated at 40 mg/kg were 0.083 mg/kg, 0.219 mg/kg, 0.279 mg/kg, and 0.310 mg/kg for weeks 2, 4, 6 and 8 respectively and 0.159 mg/kg, 0.400mg/kg, 0.572 mg/kg, 0.632 mg/kg at 80 mg/kg respectively while in clay soil, the arsenic concentration was 0.079 mg/kg and 0.167 mg/kg for weeks 2 and 4 at 40 mg/kg and 0.190 mg/kg and 0.320mg/kg for 80 mg/kg for weeks 2 and 4 respectively. No growth was recorded in weeks 6 and 8. The mean values of the arsenic concentration in the plant spiked with 40 mg/kg and 80 mg/kg respectively were significantly different (p&lt;0.05)from each other but that for the loamy soil at 40 mg/kg was not significantly different (p&gt;0.05).The Estimated Daily Intake for arsenic was &lt;1, Target Hazard Quotient was &lt; 1 and the Health Risk Index for adults that would be exposed to arsenic was &lt;1 except for the loamy soil which was ≥ 1 at week 4 and 6 for treatment level 80 mg/kg.&#x0D; Conclusion: Arsenic concentration increases in the plant with increasing period of growth, while in the soil, the reverse occurs. The result shows that the waterleaf plant absorbed heavy metal (Arsenic) from the contaminated soils but at concentrations that do not pose any health risk within the experimental period of exposure. However, it is possible that with extended duration of exposure, consumption of plants exposed to contaminated soils with heavy metals could be hazardous.

Seismic Resilience Assessment Strategy for Social and Sustainability Impact Evaluation on Transportation Road Network: A Seismic Liquefaction-Induced Damage Application

Transport networks play a critical role for living communities, as they facilitate the exchange of people and goods and foster economic growth. Improving their resilience against seismic hazards, among which liquefaction is by far one of the most significant and complex, is consistent with most of the Sustainable Development Goals pinpointed by the United Nations’ Agenda. In this paper, an original methodological framework, combining innovative Geo-statistical approaches to analyze soil properties, prediction models for soil liquefaction, and calibrated transport demand models providing the social and economic cost associated with seismic-induced road damages and closures within a renewed Geographical Information Systems (GIS) workspace, is proposed. In particular, based on traditional risk assessment evaluation, an innovative approach to evaluate the exposure in terms of economic loss due to lack of accessibility is presented. The methodology is applied to a district area in northern Italy that underwent a recent seismic event that caused several soil liquefaction phenomena. Results provided by a sensitivity analysis on a stochastic (return period) basis are derived: as the seismic intensity increases, the total social costs increase, but the trend of the rates due to traffic delays and the loss of accessibility are irregular. Although further simulation scenarios need to be undertaken, the proposed methodology seems to provide an effective planning tool to evaluate preventive strategies aimed at improving the resilience of transport networks against liquefaction risk.

Research on Three-Phase Saturation Distribution Based on Microfluidic Visualization Experiment: A Case Study of Ling Xin Mining Area

Flow characteristics and phase distribution of concentrated brine storage in mining area have been core factors linking to the leakage risk assessment and ecological evaluation. Notably, saturation plays a crucial role in impacting the flow characteristics and distribution of brine, while the existence of oil left by mining machines and original reservoir and gas produced from coal bed gas and air has complicated the issue. In this work, we conducted the microfluidic visualization experiments to reveal the saturation distribution during brine storage in mining area. We applied machine learning model to extract saturation data from experimental images with over 95% accuracy. Eventually, we found that the existence of gas significantly impacts on the saturation distribution in micropores accounting for more than 80% contribution. We clarified that the gas production rate of median 200 μL/min impacts the least on saturation variation. Results in this research are of significance for deeper comprehension on three-phase saturation characteristics of concentrated brine storage in mining area.

Spatiotemporal evaluation of water quality and risk assessment of heavy metals in the northern Caspian Sea bounded by Kazakhstan

The water quality of the northern Caspian Sea has not been well-known, and its contamination can adversely affect the health of swimmers and seashore residents. The study sought to determine the contamination state of the Caspian Sea in Kazakhstan and quantify human health risks coming from the existing heavy metals concentration. The Caspian Sea was found to be “fairly to marginally” contaminated (24 < CCME-WQI < 64), with Cd influencing the index significantly. Concentrations of Cd and Pb increase over time (seasonal Kendall test, p-values = 2–4 %) in sites near oil fields and ports, suggesting the significant role of anthropogenic sources in causing diverse pollution events. Pb demonstrated the highest variability and number of outliers (4.3 % of all samples with coefficients of variation reaching up to 175 %). The principal component analysis further revealed that various discharges from oilfields and upstream transport could contribute to the contamination by heavy metals and their concentrations. Contamination is associated with up to 6 % cancer risk for adults. The long exposure duration of swimmers in water increases risks by up to 18 %, indicating the local population is at a higher risk. In conclusion, statistical tests and analysis indicate the presence of anthropogenic sources, and risk assessment reveals swimming can contribute to cancer risk.

Hydrochemical evaluation of groundwater quality and human health risk assessment of trace elements in the largest mining district of South Khorasan, Eastern Iran.

The groundwater resources of mining areas have been in a challenging condition in terms of metal pollution and human health. Therefore, this study investigated the concentration of cobalt (Co), molybdenum (Mo), selenium (Se), tin (Sn), and antimony (Sb) in groundwater samples (wells, qanats, and springs) in a heavily contaminated mining district, South Khorasan, Eastern Iran. Human health risk of the studied metals to target groups was assessed, and water quality of the studied groundwater was investigated in the study area. A total of 367 sampling sites (279 wells, 74 qanats, and 14 springs) in South Khorasan Province were selected to collect the groundwater samples from June to July 2020. Sampling was performed thrice for each sampling point, and hydrochemical parameters were evaluated using a portable multiparameter. Inductively coupled plasma mass spectrometry (ICP-MS) was used to detect the metal concentrations. Results showed an order of Se > Mo > Sn > Co > Sb, and hazard index (HI) demonstrated a warning condition for south of South Khorasan (drinking application), southwest of South Khorasan (Irrigation application), and east and center of South Khorasan (drinking-irrigation application). Hydrochemical parameters showed a classification of "Na + K type" and "Mixed Ca-Mg-Cl type" with an overall group of "Na-Cl-HCO3" for sampled waters. Ficklin-Caboi diagram depicted a classification of "near-neutral low metal," and Schoeller diagram classified studied groundwater as "good" for drinking and irrigation consumptions and "Na-Cl" type based on ion balance diagram. Based on the correlation analysis, positive relationships were recorded among EC, TDS, Cl-, Na+, sulfate, Ca2+, salt, total hardness, Mg2+, ammonia, and K+ measured in the water samples. In essence, arid regions of the world greatly rely upon groundwater resources for drinking and irrigation consumptions, and mining districts with a heavy load of active mines can be a serious threat to the groundwater quality and human health.

Model‐based risk assessment evaluation

Risk assessment (RA) belongs to the core parts of an organizational risk management process. The primary goals of a RA are the identification, estimation and prioritization of risk(s) to organizational operations. The existing quantitative analysis of RA is focusing on the risk factors, that is, threat or vulnerability. However, the quantitative metrics of the assessment have not been formally defined and modeled yet. Consequently, it is essential to define a formal model and relevant security metrics for RA within an organization. In this study, we will use a complete lattice to analyze risk factors. Moreover, a formal model will be defined to describe the RA process. The reachability of the model will be discussed. Quantitative metrics will be defined to provide insight on the risk estimation. The model can be expressed using colored Petri nets. This study can assist chief information security officers analyze security risks in their organizations and help them balance the security budget in their organizations.

Evaluation of Natural Radioactivity and Risk Assessment of Radon in Surface Soils from Gold Mining Areas

Evaluation of Natural Radioactivity and Risk Assessment of Radon in Surface Soils from Gold Mining Areas

Balancing non-discriminatory donor selection and blood safety in the Netherlands: Evaluation of an individual risk assessment of sexual behavior.

To better balance the safety of the blood supply and the inclusion of men who have sex with men (MSM), further improvements are needed to the risk management strategy employed in the Netherlands to reduce transfusion-transmissible infections (TTIs). A gender-neutral individual risk assessment could provide a solution by determining donor eligibility based on sexual behaviors known to increase the risk of TTIs. Our objective is to estimate the proportion of blood donors that would be deferred by such an assessment, as well as their discomfort answering such questions. Two surveys were distributed in May 2020 to assess sexual behavior in blood donors in the last 4, 6, and 12 months, as well as their discomfort reporting such information. A combination of both surveys measured the extent to which discomfort was associated with reporting sexual behavior. A high-risk sexual behavior pattern was defined as having had multiple sexual partners and having engaged in anal sex, without consistent condom use. Of all 2177 participating whole blood donors, 0.8% report engaging in high-risk sexual behaviors over the last 4 months and would therefore be ineligible to donate. When accounting for the additional proportion of donors that reported such questions would stop them from donating, 2.0% and 3.2% of female and male donors, respectively, would be lost. Gender-neutral eligibility criteria based on high-risk sexual behaviors may reduce the overall number of eligible donors in the Netherlands, but could make blood donation more accessible to a broader group of donors.

Estimating cobalt exposure in respirable dust from cobalt in inhalable dust.

Cobalt is a commonly used element in metal industry. Exposure to workers occurs mainly by inhalation of cobalt-containing dust. For the evaluation of cobalt exposure, risk assessment and investigations on occupational diseases, measurements of cobalt in respirable dust are needed. Up to now, often only data for cobalt in inhalable dust are available, which is due to the earlier classification of the limit value in this fraction. Therefore, a possibility to convert cobalt concentrations mathematically from inhalable into respirable concentrations is desirable. In this study, 639 parallel measurements of cobalt concentrations in inhalable (cI(Co)) and respirable dust fractions (cR(Co)) were extracted from the non-public exposure database MEGA (Measurement data relating to workplace exposure to hazardous substances, maintained at the Institute for Occupational Safety and Health of the German Social Accident Insurance) and investigated by regression analysis. For the whole dataset regression shows high quality measures (correlation coefficient R=0.888, adjusted coefficient of determination adj. R2=0.788 - R2 is adjusted to sample size). Further description of the data is achieved by splitting the dataset according to the type of sampling ('stationary' and 'personal') and three working activity groups, 'high temperature processing', 'filling/transport/storage', and 'machining/abrasive techniques' (0.845 ≤ R≤0.876; 0.711 ≤ adj. R2 ≤ 0.762). As subgroups of 'high temperature processing' and 'machining/abrasive techniques' two further groups could be determined. These groups are called heuristic groups, since they have to be formed non-systematically by trial and error. These heuristic groups are 'welding' and 'grinding'. They are more selective on the included working activities with adj. R2 of 0.703 and 0.748 respectively. The resulting conversion functions of all groups are power functions with exponents between 0.704 and 0.794. For the estimation of cobalt in respirable dust in other studies, it is possible to use the conversion functions of the heuristic and working activity groups. Limitations of the possibility to use the conversion functions are discussed.

Evaluation of Post-OP Complications using Risk Assessment Tool; Attitude of Surgeons

Objective: Current study was designed to assess the attitude of surgeons towards the use of surgical risk assessment tools in Sargodha. Method: This study was of descriptive crossectional nature. It was a survey based study conducted in a 4 tertiary care hospitals of Sargodha. Data of 30 surgeons was collected using a questionnaire. Frequencies and percentages were calculated to interpret results. Results: The usage of online risk calculator was never used by majority of surgeons (83.33%). Risk assessment is always based on prior experience (76.67%). Evaluation of risk assessment based on existing literature is always practiced by 53.33% surgeons. Conclusion: majority of surgeons are not using risk assessment calculator in surgical settings. They are focusing on prior experience based assessment of post-op complications. The briefing time given by surgeon to the patients while communicating their risk assessment is very less which should be maintained by the hospital management. Keywords: Risk Assessment, Post-op Complications, Surgeons, Infections

Research on Safety Evaluation Method of Hydrogen Diaphragm Compressor Based on Multi-Model Weighted Combination

By establishing a remote monitoring system for the hydrogen diaphragm compressor, the thermodynamic real-time performance parameters of the unit are obtained. Using the multi-model weighted combination method, the safety evaluation system of hydrogen diaphragm compressors is established, and the risk assessment and safety evaluation analysis of three hydrogen diaphragm compressors are carried out. The analysis and calculation results show that the three hydrogen diaphragm compressors are all within the rating range of safe operation, which verifies that the multi-model weighted combination is a high-precision unit safety evaluation method, which can be used to evaluate the safe operation status of the hydrogen diaphragm compressor, so as to ensure the long-term safe and stable operation of the pressurized equipment of the hydrogen refueling station.

Determination of pollutions in the surface of water samples from Ogbajarajara river, Nigeria by spectrophotometer and atomic absorption spectrometry before evaluation of health risk assessment

Determination of environmental pollution in the surface water is very important. So, in this study, determination, and health risk assessment were evaluated. The pollutions such as anions, cations, and heavy metals were analyzed in surface water by photometer spectrometry and atomic absorption spectrometry (AAS). TDS for wet and dry seasons go from 122.17±1.74 mg L-1 to 63.80±0.86 mg L-1. The high phosphate levels in both wet and dry seasons are recorded from 60.74±0.61 - 60.27±0.38 mg L-1 in both seasons. Iron values observed range from 8.42±0.06 to 6.28±0.11 mg L-1 in the wet and dry season, Cu was recorded between 0.08±0.01 - 0.07±0.01 mg L-1, Mn recorded from 0.07±0.01 to 0.06±0.01 mg L-1, Zn recorded between 2.29±0.09 - 1.15±0.09 mg L-1, and Pb recorded from 0.69±0.09 to 0.40±0.18 mg L-1 while Cd and Ni were not detected in the study. Water quality index (WQI) values were determined as 549 for wet and 328 for the dry season, the hazard indices for both seasons are below one. The outcomes in this present study showed that the level of Pb in the surface water could present a carcinogenic risk to both adults and children. All heavy metals results were validated by ET-AAS.

Non-native freshwater fishes in Guatemala, northern Central America: introduction sources, distribution, history, and conservation consequences

Non-native freshwater fishes have been introduced to Guatemalan freshwater ecosystems since the beginning of the last century without prior risk assessment or subsequent evaluation of their impacts. We synthesized historical records, and distributional data from a literature review, online databases and museum records of non-native freshwater fishes in Guatemala. We found records for 22 non-native freshwater fishes with the oldest records dating back to 1926. Non-native freshwater fishes were recorded in 64% of the river sub-basins in Guatemala and we identified that at least 12 species have established populations. The Jaguar guapote (Parachromis managuensis) and Tilapias (Oreochromis spp.) are the most widespread non-native fishes. The species of non-native freshwater fishes introduced indicates that they are human selected (e.g., for farming purposes). Our work shows that aquaculture has been the major driver of introductions in the country, but aquarium release has become an important source in the last 20 years. Given the potential impact of non-native freshwater fishes on native fauna and ecosystems, we highlight an urgent need to assess their ecological effects, as well as to establish a fish fauna monitoring program in Guatemala to detect new introductions. Government and non-governmental agencies should promote the use of native species to supply fish demands in alignment with environmental policies and the objectives of the fishing agency in Guatemala.

Assessment of the COVID-19 infection risk at a workplace through stochastic microexposure modeling.

BackgroundThe COVID-19 pandemic has a significant impact on economy. Decisions regarding the reopening of businesses should account for infection risks.ObjectiveThis paper describes a novel model for COVID-19 infection risks and policy evaluations.MethodsThe model combines the best principles of the agent-based, microexposure, and probabilistic modeling approaches. It takes into account specifics of a workplace, mask efficiency, and daily routines of employees, but does not require specific inter-agent rules for simulations. Likewise, it does not require knowledge of microscopic disease related parameters. Instead, the risk of infection is aggregated into the probability of infection, which depends on the duration and distance of every contact. The probability of infection at the end of a workday is found using rigorous probabilistic rules. Unlike previous models, this approach requires only a few reference data points for calibration, which are more easily collected via empirical studies.ResultsThe application of the model is demonstrated for a typical office environment and for a real-world case.ConclusionThe proposed model allows for effective risk assessment and policy evaluation when there are large uncertainties about the disease, making it particularly suitable for COVID-19 risk assessments.