scholarly journals A Coupled Experimental and Statistical Approach for an Assessment of the Airborne Infection Risk in Event Locations

2022 ◽  
Author(s):  
Lukas Siebler ◽  
Torben Rathje ◽  
Maurizio Calandri ◽  
Konstantinos Stergiaropoulos ◽  
Bernhard Richter ◽  
...  
Keyword(s):  
Measurement Data ◽  
Epidemiological Data ◽  
Trace Gas ◽  
Vaccination Rates ◽  
Airborne Infection ◽  
Reproduction Numbers ◽  
Gas Measurements ◽  
Infection Processes ◽  
Flexible Application ◽  
First Time

Operators of event locations are particularly affected by a pandemic. Resulting restrictions may cause uneconomical business. With previous models, only an incomplete quantitative risk assessments is possible, whereby no suitable restrictions can be derived. Hence, a mathematical and statistical model has been developed in order to link measurement data of substance dispersion in rooms with epidemiological data like incidences, reproduction numbers, vaccination rates and test qualities. This allows a first time overall assessment of airborne infection risks in large event locations. In these venues displacement ventilation concepts are often implemented. In this case simplified theoretical assumptions fail for the prediction of relevant airflows for infection processes. Thus, with locally resolving trace gas measurements and specific data of infection processes, individual risks can be computed more detailed. Via inclusion of many measurement positions, an assessment of entire event locations is possible. Embedding the overall model in a flexible application, daily updated epidemiological data allow latest calculations of expected new infections and individual risks of single visitors for a certain event. With this model, an instrument has been created that can help policymakers and operators to take appropriate measures and to check restrictions for their effect.

Stratospheric Trace Gas Measurements in the Near-UV and Visible Spectral Range with the Sun as a Light Source Using a Fourier Transform Spectrometer

1996 ◽  
Vol 50 (5) ◽  
pp. 583-587 ◽  
Author(s):  
Justus Notholt ◽  
Klaus Pfeilsticker
Keyword(s):  
Fourier Transform ◽  
Spectral Range ◽  
Visible Spectral Range ◽  
The Arctic ◽  
Trace Gas ◽  
Fourier Transform Spectrometer ◽  
The Sun ◽  
Gas Measurements ◽  
Atmospheric Trace Gas ◽  
First Time

Spectra of the atmosphere have been measured in the near-UV and visible spectral range for the first time with a Fourier transform spectrometer using direct and zenith scattered sunlight. The observations were performed in the Arctic at 79°N, 12°E in 1994. Spectra were recorded in the wavelength range 310 to 1100 nm up to a resolution of about 0.0008 nm. The use of the FT spectrometer allowed the study of atmospheric trace gas concentrations in the whole spectral region between 500 and 31,000 cm−1 (0.3–20 μm) with one instrument by only changing the beamsplitters and choosing different detectors. At a spectral resolution of 1.2 nm, the atmospheric absorptions of O3 around 505 nm and NO2 at 448 nm were analyzed. Results are compared with observations performed in the infrared with the same instrument, with TOMS data and with ozone balloon data.

scholarly journals An assessment of the climatological representativeness of IAGOS-CARIBIC trace gas measurements using EMAC model simulations

2016 ◽  
Author(s):  
Johannes Eckstein ◽  
Roland Ruhnke ◽  
Andreas Zahn ◽  
Marco Neumaier ◽  
Ole Kirner ◽  
...  
Keyword(s):  
Climate Model ◽  
Trace Gases ◽  
Measurement Data ◽  
Trace Gas ◽  
Statistical Measures ◽  
Kolmogorov Smirnov ◽  
Gas Measurements ◽  
Passenger Aircraft ◽  
Relative Differences ◽  
Smirnov Test

Abstract. Measurement data from the long-term passenger aircraft project IAGOS-CARIBIC is often used to derive trace gas climatologies. We investigate to what extent such derived climatologies can be assumed to be representative for the true state of the atmosphere. Using the chemistry-climate model EMAC we sample the modelled trace gases along CARIBIC flight tracks. Different trace gases are considered and climatologies relative to the mid-latitude tropopause are calculated. Representativeness can now be assessed by comparing the CARIBIC sampled model data to the true climatological model state. Three statistical methods are applied for this purpose: the Kolomogorov-Smirnov test, and scores based on the variability and relative differences. Generally, representativeness is expected to decrease with increasing variability and to increase with the number of available samples. Based on this assumption, we investigate the suitability of the different statistical measures for our problem. The Kolmogorov-Smirnov test seems too strict and does not identify any climatology as representative – not even long lived well observed trace gases. In contrast, the variability based scores pass the general requirements for representativeness formulated above. In addition, even the simplest metric (relative differences) seems applicable for investigating representativeness. Using the relative differences score we investigate the representativeness of a large number of different trace gases. For our final consideration we assume that the EMAC model is a reasonable representation of the real world and that representativeness in the model world can be translated to representativeness for CARIBIC measurements. This assumption is justified by comparing the model variability to the variability of CARIBIC measurements. Finally, we show how the representativeness score can be translated into a number of flights necessary to achieve a certain degree of representativeness.

scholarly journals Soil gas probes for monitoring trace gas messengers of microbial activity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Joseph R. Roscioli ◽  
Laura K. Meredith ◽  
Joanne H. Shorter ◽  
Juliana Gil-Loaiza ◽  
Till H. M. Volkmann
Keyword(s):  
Microbial Activity ◽  
Soil Heterogeneity ◽  
Soil Gas ◽  
Microbial Processes ◽  
Trace Gas ◽  
Soil Microbiome ◽  
Sampling System ◽  
Site Specific ◽  
Gas Measurements ◽  
Subsurface Monitoring

AbstractSoil microbes vigorously produce and consume gases that reflect active soil biogeochemical processes. Soil gas measurements are therefore a powerful tool to monitor microbial activity. Yet, the majority of soil gases lack non-disruptive subsurface measurement methods at spatiotemporal scales relevant to microbial processes and soil structure. To address this need, we developed a soil gas sampling system that uses novel diffusive soil probes and sample transfer approaches for high-resolution sampling from discrete subsurface regions. Probe sampling requires transferring soil gas samples to above-ground gas analyzers where concentrations and isotopologues are measured. Obtaining representative soil gas samples has historically required balancing disruption to soil gas composition with measurement frequency and analyzer volume demand. These considerations have limited attempts to quantify trace gas spatial concentration gradients and heterogeneity at scales relevant to the soil microbiome. Here, we describe our new flexible diffusive probe sampling system integrated with a modified, reduced volume trace gas analyzer and demonstrate its application for subsurface monitoring of biogeochemical cycling of nitrous oxide (N2O) and its site-specific isotopologues, methane, carbon dioxide, and nitric oxide in controlled soil columns. The sampling system observed reproducible responses of soil gas concentrations to manipulations of soil nutrients and redox state, providing a new window into the microbial response to these key environmental forcings. Using site-specific N2O isotopologues as indicators of microbial processes, we constrain the dynamics of in situ microbial activity. Unlocking trace gas messengers of microbial activity will complement -omics approaches, challenge subsurface models, and improve understanding of soil heterogeneity to disentangle interactive processes in the subsurface biome.

scholarly journals An evaluation of the performance of chemistry transport models by comparison with research aircraft observations. Part 1: Concepts and overall model performance

2003 ◽  
Vol 3 (5) ◽  
pp. 1609-1631 ◽  
Author(s):  
D. Brunner ◽  
J. Staehelin ◽  
H. L. Rogers ◽  
M. O. Köhler ◽  
J. A. Pyle ◽  
...  
Keyword(s):  
Quantitative Methods ◽  
Climate Models ◽  
Model Performance ◽  
Average Concentration ◽  
Convective Transport ◽  
Trace Gas ◽  
Atmospheric Conditions ◽  
Time Step ◽  
Research Aircraft ◽  
Gas Measurements

Abstract. A rigorous evaluation of five global Chemistry-Transport and two Chemistry-Climate Models operated by several different groups in Europe, was performed. Comparisons were made of the models with trace gas observations from a number of research aircraft measurement campaigns during the four-year period 1995-1998. Whenever possible the models were run over the same four-year period and at each simulation time step the instantaneous tracer fields were interpolated to all coinciding observation points. This approach allows for a very close comparison with observations and fully accounts for the specific meteorological conditions during the measurement flights. This is important considering the often limited availability and representativity of such trace gas measurements. A new extensive database including all major research and commercial aircraft measurements between 1995 and 1998, as well as ozone soundings, was established specifically to support this type of direct comparison. Quantitative methods were applied to judge model performance including the calculation of average concentration biases and the visualization of correlations and RMS errors in the form of so-called Taylor diagrams. We present the general concepts applied, the structure and content of the database, and an overall analysis of model skills over four distinct regions. These regions were selected to represent various atmospheric conditions and to cover large geographical domains such that sufficient observations are available for comparison. The comparison of model results with the observations revealed specific problems for each individual model. This study suggests the further improvements needed and serves as a benchmark for re-evaluations of such improvements. In general all models show deficiencies with respect to both mean concentrations and vertical gradients of important trace gases. These include ozone, CO and NOx at the tropopause. Too strong two-way mixing across the tropopause is suggested to be the main reason for differences between simulated and observed CO and ozone values. The generally poor correlations between simulated and measured NOx values suggest that in particular the NOx input by lightning and the convective transport from the polluted boundary layer are still not well described by current parameterizations, which may lead to significant differences in the spatial and seasonal distribution of NOx in the models. Simulated OH concentrations, on the other hand, were found to be in surprisingly good agreement with measured values.

scholarly journals The high Arctic in extreme winters: vortex, temperature, and MLS and ACE-FTS trace gas evolution

2008 ◽  
Vol 8 (3) ◽  
pp. 505-522 ◽  
Author(s):  
G. L. Manney ◽  
W. H. Daffer ◽  
K. B. Strawbridge ◽  
K. A. Walker ◽  
C. D. Boone ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Lower Stratosphere ◽  
High Arctic ◽  
Trace Gas ◽  
Satellite Measurements ◽  
Broadband Emission ◽  
Gas Measurements ◽  
Chemistry Experiment ◽  
Very High ◽  
Good Agreement

Abstract. The first three Arctic winters of the ACE mission represented two extremes of winter variability: Stratospheric sudden warmings (SSWs) in 2004 and 2006 were among the strongest, most prolonged on record; 2005 was a record cold winter. Canadian Arctic Atmospheric Chemistry Experiment (ACE) Validation Campaigns were conducted at Eureka (80° N, 86° W) during each of these winters. New satellite measurements from ACE-Fourier Transform Spectrometer (ACE-FTS), Sounding of the Atmosphere using Broadband Emission Radiometry (SABER), and Aura Microwave Limb Sounder (MLS), along with meteorological analyses and Eureka lidar temperatures, are used to detail the meteorology in these winters, to demonstrate its influence on transport, and to provide a context for interpretation of ACE-FTS and validation campaign observations. During the 2004 and 2006 SSWs, the vortex broke down throughout the stratosphere, reformed quickly in the upper stratosphere, and remained weak in the middle and lower stratosphere. The stratopause reformed at very high altitude, near 75 km. ACE measurements covered both vortex and extra-vortex conditions in each winter, except in late-February through mid-March 2004 and 2006, when the strong, pole-centered vortex that reformed after the SSWs resulted in ACE sampling only inside the vortex in the middle through upper stratosphere. The 2004 and 2006 Eureka campaigns were during the recovery from the SSWs, with the redeveloping vortex over Eureka. 2005 was the coldest winter on record in the lower stratosphere, but with an early final warming in mid-March. The vortex was over Eureka at the start of the 2005 campaign, but moved away as it broke up. Disparate temperature profile structure and vortex evolution resulted in much lower (higher) temperatures in the upper (lower) stratosphere in 2004 and 2006 than in 2005. Satellite temperatures agree well with lidar data up to 50–60 km, and ACE-FTS, MLS and SABER show good agreement in high-latitude temperatures throughout the winters. Consistent with a strong, cold upper stratospheric vortex and enhanced radiative cooling after the SSWs, MLS and ACE-FTS trace gas measurements show strongly enhanced descent in the upper stratospheric vortex in late January through March 2006 compared to that in 2005.

scholarly journals Estimation of age-stratified contact rates during the COVID-19 pandemic using a novel inference algorithm

2022 ◽  
Author(s):  
Christopher M Pooley ◽  
Andrea B Doeschl-Wilson ◽  
Glenn Marion
Keyword(s):  
Hospital Admissions ◽  
Epidemiological Data ◽  
Joint Analysis ◽  
Model Parameters ◽  
Inference Algorithm ◽  
Public Response ◽  
Contact Rates ◽  
Reproduction Numbers ◽  
Public Data ◽  
Approximate Bayesian

Well parameterised epidemiological models including accurate representation of contacts, are fundamental to controlling epidemics. However, age-stratified contacts are typically estimated from pre-pandemic/peace-time surveys, even though interventions and public response likely alter contacts. Here we fit age-stratified models, including re-estimation of relative contact rates between age-classes, to public data describing the 2020-21 COVID-19 outbreak in England. This data includes age-stratified population size, cases, deaths, hospital admissions, and results from the Coronavirus Infection Survey (almost 9000 observations in all). Fitting stochastic compartmental models to such detailed data is extremely challenging, especially considering the large number of model parameters being estimated (over 150). An efficient new inference algorithm ABC-MBP combining existing Approximate Bayesian Computation (ABC) methodology with model-based proposals (MBP) is applied. Modified contact rates are inferred alongside time-varying reproduction numbers that quantify changes in overall transmission due to pandemic response, and age-stratified proportions of asymptomatic cases, hospitalisation rates and deaths. These inferences are robust to a range of assumptions including the values of parameters that cannot be estimated from available data. ABC-MBP is shown to enable reliable joint analysis of complex epidemiological data yielding consistent parametrisation of dynamic transmission models that can inform data-driven public health policy and interventions.

scholarly journals Prediction of local geomagnetic activity on the example of data of “Lviv” Magnetic Observatory

2021 ◽  
Vol 27 (1) ◽  
pp. 78-84
Author(s):  
D.I. Vlasov ◽  
◽  
A.S. Parnowski ◽  
Keyword(s):  
Predictive Models ◽  
Lead Time ◽  
Measurement Data ◽  
Correlation Coefficients ◽  
Skill Score ◽  
Magnetic Observatory ◽  
Using Data ◽  
First Time ◽  
Prediction Efficiency ◽  
Main Center

For the first time in world practice, predictive models were constructed for X, Y, Z geomagnetic elements. Based on these models, the prediction was made with 3 hours lead time using data of the “Lviv” magnetic observatory. The properties of models are as follows: observatory — LVV, рredicted values — XYZ; lead time — 3 hours; correlation coefficients’ averaged measurement data — 0.824 (X), 0.811 (Y), 0.804 (Z); prediction efficiency — 0.816 (X), 0.803 (Y), 0.801 (Z); skill score — 0.115 (X), 0.095 (Y), 0.099 (Z). The developed models were tested in the Main Center of Special Monitoring, and they were found to meet the Basic Requirements for operational predictive models.

Atmospheric trace gas measurements at Palmer Station, Antarctica: 1982?83

1984 ◽  
Vol 2 (1) ◽  
pp. 65-81 ◽  
Author(s):  
E. Robinson ◽  
W. L. Bamesberger ◽  
F. A. Menzia ◽  
A. S. Waylett ◽  
S. F. Waylett
Keyword(s):  
Trace Gas ◽  
Palmer Station ◽  
Gas Measurements ◽  
Atmospheric Trace Gas

Vaccination Against COVID-19: Emerging Issues and Future Prospects

2021 ◽  
Vol 76 (6) ◽  
pp. 652-660
Author(s):  
Gennadiy G. Onischenko ◽  
Tatiana E. Sizikova ◽  
Vitaliy N. Lebedev ◽  
Sergey V. Borisevich
Keyword(s):  
Effective Means ◽  
Herd Immunity ◽  
High Rate ◽  
Vaccination Rates ◽  
Actual Duration ◽  
Entire Duration ◽  
Mass Immunization ◽  
Emerging Issues ◽  
First Time

The most effective means of combating the COVID-19 pandemic s the formation of herd immunity, with the formation of an immune population to infection. Vaccination rates are continuously increasing. In early February 2021, WHO announced that the number of people vaccinated against the disease for the first time exceeded the number of infected. In early June 2021 the vaccinated number exceeded 2 billion which is more than 12 times the total number infected for the entire duration of the pandemic. The high rate of vaccination leads to the formulation of a number of questions concerning the effectiveness of vaccines currently used for mass immunization the level of herd immunity, necessary to stop the spread of the disease, the actual duration of the vaccination carried out, long-term prospects of the platforms, used in the creation of vaccines. The purpose of this paper is to substantiate reasoned answers to the questions posed.

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