scholarly journals Low Cost tool for finding ventilation rates for Airborne Infection Control in the Built Environment

2020 ◽  
Author(s):  
Raja Singh
Keyword(s):  
Carbon Dioxide ◽  
Natural Ventilation ◽  
Low Cost ◽  
Ambient Air ◽  
Disease Spread ◽  
Indoor Space ◽  
Airborne Infection ◽  
New Apparatus ◽  
The Cost ◽  
Ventilation Rates

Dilution Ventilation is an accepted way of providing Natural Ventilation for reduction of Disease spread in Indoor Spaces. It is most relevant in low resource settings where the cost of advanced technologies may be a barrier. Studies have been performed in India to find a correlation between Ventilation of spaces and its role in the prevention of Tuberculosis, which is a major airborne disease with high incidence levels in India. These studies lack the measurement of the air changes in the room which is an important criterion to find out the disease spread by transmission models. This paper presents a new apparatus prepared to measure Air changes in an indoor space using Carbon Dioxide as a biomarker which acts as a surrogate for the ventilation in the space. The apparatus prepared uses a pre-existing carbon dioxide meter but adds value to it by creating a tamper-proof, vandal-resistant and a poke-resistant system. It also includes a built-in air suction and withdrawal system so that the sensor can be supplied with the ambient air in the room so that it can accurately give the carbon dioxide measurements. The study enhances the methods of investigation for Indoor Air Quality studies.

scholarly journals Predictive and retrospective modelling of airborne infection risk using monitored carbon dioxide

2021 ◽  
pp. 1420326X2110435
Author(s):  
Henry C. Burridge ◽  
Shiwei Fan ◽  
Roderic L. Jones ◽  
Catherine J. Noakes ◽  
P. F. Linden
Keyword(s):  
Carbon Dioxide ◽  
Absolute Risk ◽  
Infection Risk ◽  
Expected Number ◽  
Indoor Space ◽  
Airborne Infection ◽  
Secondary Infections ◽  
School Classroom ◽  
Open Plan ◽  
Ventilation Rates

The risk of long range, herein ‘airborne', infection needs to be better understood and is especially urgent during the COVID-19 pandemic. We present a method to determine the relative risk of airborne transmission that can be readily deployed with either modelled or monitored CO2 data and occupancy levels within an indoor space. For spaces regularly, or consistently, occupied by the same group of people, e.g. an open-plan office or a school classroom, we establish protocols to assess the absolute risk of airborne infection of this regular attendance at work or school. We present a methodology to easily calculate the expected number of secondary infections arising from a regular attendee becoming infectious and remaining pre/asymptomatic within these spaces. We demonstrate our model by calculating risks for both a modelled open-plan office and by using monitored data recorded within a small naturally ventilated office. In addition, by inferring ventilation rates from monitored CO2, we show that estimates of airborne infection can be accurately reconstructed, thereby offering scope for more informed retrospective modelling should outbreaks occur in spaces where CO2 is monitored. Well-ventilated spaces appear unlikely to contribute significantly to airborne infection. However, even moderate changes to the conditions within the office, or new variants of the disease, typically result in more troubling predictions.

scholarly journals Modelling key market impacts and land allocation for biofuel production and forestry

2006 ◽  
Vol 2006 ◽  
pp. 1-12
Author(s):  
A. Korobeinikov ◽  
P. Read ◽  
A. Parshotam ◽  
J. Lermit
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Large Scale ◽  
Low Cost ◽  
Wood Products ◽  
Biofuel Production ◽  
Fuel Wood ◽  
Carbon Dioxide Levels ◽  
The Cost ◽  
The Impact

It has been suggested that the large scale use of biofuel, that is, fuel derived from biological materials, especially in combination with reforestation of large areas, can lead to a low-cost reduction of atmospheric carbon dioxide levels. In this paper, a model of three markets: fuel, wood products, and land are considered with the aim of evaluating the impact of large scale biofuel production and forestry on these markets, and to estimate the cost of a policy aimed at the reduction of carbon dioxide in the atmosphere. It is shown that the costs are lower than had been previously expected.

scholarly journals Comparing the Use of High- to Low-Cost Black Carbon and Carbon Dioxide Sensors for Characterizing On-Road Diesel Truck Emissions

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6714
Author(s):  
Rebecca A. Sugrue ◽  
Chelsea V. Preble ◽  
Thomas W. Kirchstetter
Keyword(s):  
Carbon Dioxide ◽  
Black Carbon ◽  
Emission Factor ◽  
Lower Cost ◽  
Low Cost ◽  
Ambient Air ◽  
Source Characterization ◽  
Ambient Conditions ◽  
Heavy Duty Diesel ◽  
Carbon Dioxide Co2

The exhaust plume capture method is a commonly used approach to measure pollutants emitted by in-use heavy-duty diesel trucks. Lower cost sensors, if used in place of traditional research-grade analyzers, could enable wider application of this method, including use as a monitoring tool to identify high-emitting trucks that may warrant inspection and maintenance. However, low-cost sensors have for the most part only been evaluated under ambient conditions as opposed to source-influenced environments with rapidly changing pollutant concentrations. This study compared black carbon (BC) emission factors determined using different BC and carbon dioxide (CO2) sensors that range in cost from $200 to $20,000. Controlled laboratory experiments show that traditional zero and span steady-state calibration checks are not robust indicators of sensor performance when sampling short duration concentration peaks. Fleet BC emission factor distributions measured at two locations at the Port of Oakland in California with 16 BC/CO2 sensor pairs were similar, but unique sensor pairs identified different high-emitting trucks. At one location, the low-cost PP Systems SBA-5 agreed on the classification of 90% of the high emitters identified by the LI-COR LI-7000 when both were paired with the Magee Scientific AE33. Conversely, lower cost BC sensors when paired with the LI-7000 misclassified more than 50% of high emitters when compared to the AE33/LI-7000. Confidence in emission factor quantification and high-emitter identification improves with larger integrated peak areas of CO2 and especially BC. This work highlights that sensor evaluation should be conducted under application-specific conditions, whether that be for ambient air monitoring or source characterization.

scholarly journals Numerical investigation of airborne infection in naturally ventilated hospital wards with central-corridor type

2016 ◽  
Vol 27 (1) ◽  
pp. 59-69 ◽  
Author(s):  
Qi Zhou ◽  
Hua Qian ◽  
Li Liu
Keyword(s):  
General Hospital ◽  
Natural Ventilation ◽  
Index Patient ◽  
Dynamics Simulation ◽  
World Health ◽  
Future Design ◽  
Airborne Infection ◽  
Ventilation Rates ◽  
Hospital Wards ◽  
The Impact

Natural ventilation is believed to control airborne infection due to high ventilation rates while an undesired flow pattern may cause infection transmission in hospital wards. A computational fluid dynamics simulation was carried out in this study to investigate the impact of airflow pattern on cross infection in a real central-corridor hospital ward with natural ventilation in Nanjing, China. The simulation results demonstrate that the predicted infection risks of the downstream cubicle are up to 10.48% and 11.59% as the index patient is located in the corridor and in the opposite upstream cubicle, respectively. Under this circumstance, the downstream cubicle should be listed on the high-risk list and the central-corridor type is not recommended in a naturally ventilated ward. Measures such as keeping cubicle doors closed should be taken in order to cut off the transmission route. The results not only give direct evidence to strongly support World Health Organization’s recommendation but also suggest required amendment of the Chinese standard GB 51039-2014 to improve ventilation arrangement in general hospital wards in China. Our findings are useful for improving the future design of general hospital wards for airborne infection control.

scholarly journals Evaluation and enhancement of a low-cost NDIR CO<sub>2</sub> sensor

2017 ◽  
Author(s):  
Cory R. Martin ◽  
Ning Zeng ◽  
Anna Karion ◽  
Russell R. Dickerson ◽  
Xinrong Ren ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Standard Deviation ◽  
Low Cost ◽  
Linear Regression Analysis ◽  
Ambient Air ◽  
Multivariate Linear Regression Analysis ◽  
Laser Absorption ◽  
Accuracy And Precision ◽  
Carbon Dioxide Concentrations ◽  
Ambient Air Monitoring

Abstract. Non-dispersive infrared (NDIR) sensors are a low-cost way to observe carbon dioxide concentrations in air, but their specified accuracy and precision are not sufficient for some scientific applications. An initial evaluation of six SenseAir K30 carbon dioxide NDIR sensors in a lab setting showed that without any calibration or correction, the sensors have an individual root mean square (RMS) error between ~ 5 to 21 parts per million (ppm) compared to a research-grade greenhouse gas analyzer using cavity enhanced laser absorption spectroscopy. Through further evaluation, after correcting for environmental variables with coefficients determined through a multivariate linear regression analysis, the calculated difference between the each of six individual K30 NDIR sensors and the higher-precision instrument had for one minute data a standard deviation of between 1.6 ppm and 4.4 ppm. The median standard deviation improved from 8.08 for off the shelf sensors to 1.89 ppm after correction and calibration, demonstrating the potential to provide useful information for ambient air monitoring.

scholarly journals Simulation and Analysis of Various Ventilation Systems Given in an Example in the Same School of Indoor Air Quality

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2845 ◽  
Author(s):  
Katarzyna Gładyszewska-Fiedoruk ◽  
Vasyl Zhelykh ◽  
Andrii Pushchinskyi
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Carbon Dioxide Concentration ◽  
Additional Energy ◽  
Exhaust Ventilation ◽  
Building Ventilation ◽  
The Cost

The quality of internal air is one of the factors that affect the pace and quality of knowledge acquisition. Therefore, it is important that classrooms have high quality of air. Using computer simulation, the effect of various building ventilation variants on air quality in classrooms was analyzed. Two criteria were analyzed and six variants of ventilation. The analysis was carried out using the CONTAMW program, used for multi-zone analysis of ventilation and air quality in a building. As an indicator of air quality, the concentration of carbon dioxide in school halls was adopted. The analyses show that natural ventilation is not able to provide proper air exchange. Regular airing of classrooms during breaks can reduce the carbon dioxide concentration to 2500 ppm, however, there is a significant reduction in indoor temperature (even below 10 °C). The best control over the internal environment can be obtained by using a supply–exhaust ventilation system with heat recovery. Obtaining a higher stabilization of ventilation is achieved by supplying additional energy to drive fans, however, this is only a small amount of energy compared to the cost of heat for heating the building (maximum 2%).

scholarly journals Programmable low-cost DNA-based platform for viral RNA detection

2020 ◽  
Vol 6 (39) ◽  
pp. eabc6246 ◽  
Author(s):  
Lifeng Zhou ◽  
Arun Richard Chandrasekaran ◽  
Jibin Abraham Punnoose ◽  
Gaston Bonenfant ◽  
Stephon Charles ◽  
...  
Keyword(s):  
Zika Virus ◽  
Ebola Virus ◽  
Biological Fluids ◽  
Low Cost ◽  
Rna Extraction ◽  
Viral Rna ◽  
Disease Spread ◽  
Rna Detection ◽  
The Cost ◽  
Further Development

Detection of viruses is critical for controlling disease spread. Recent emerging viral threats, including Zika virus, Ebola virus, and SARS-CoV-2 responsible for coronavirus disease 2019 (COVID-19) highlight the cost and difficulty in responding rapidly. To address these challenges, we develop a platform for low-cost and rapid detection of viral RNA with DNA nanoswitches that mechanically reconfigure in response to specific viruses. Using Zika virus as a model system, we show nonenzymatic detection of viral RNA with selective and multiplexed detection between related viruses and viral strains. For clinical-level sensitivity in biological fluids, we paired the assay with sample preparation using either RNA extraction or isothermal preamplification. Our assay requires minimal laboratory infrastructure and is adaptable to other viruses, as demonstrated by quickly developing DNA nanoswitches to detect SARS-CoV-2 RNA in saliva. Further development and field implementation will improve our ability to detect emergent viral threats and ultimately limit their impact.

scholarly journals Influence of different systems of minimum ventilation on air quality in broiler houses

2012 ◽  
Vol 32 (6) ◽  
pp. 1024-1033 ◽  
Author(s):  
Irene Menegali ◽  
Ilda F. F. Tinôco ◽  
Sérgio Zolnier ◽  
Cinara da C. S. Carvalho ◽  
Maria C. de C Guimarães
Keyword(s):  
Carbon Monoxide ◽  
Air Quality ◽  
Physical Environment ◽  
Natural Ventilation ◽  
Ambient Air ◽  
Positive Pressure ◽  
Broiler Chicks ◽  
Air Velocity ◽  
Ventilation Rates ◽  
Ventilation Systems

To maintain a competitive development of the Brazilian aviculture, some measures must be taken to enable the identification and reduction of risks to the health of birds, as well as for the physical environment. Therefore, the aim of this study was to evaluate the effectiveness of three different systems of minimum ventilation (positive pressure - SVMP, negative pressure - SVMN and natural ventilation - SVMNat) in the air quality during the first 21 days of life of broiler chicks, during winter. Three points were selected along the length to verify ammonia, carbon monoxide and oxygen concentrations at 3a.m., 9a.m., 3p.m. and 9p.m., by the respiration level of birds and workers. The averages of pollutant gases did not exceed the tolerance levels for the three minimum ventilation systems evaluated, which is 20 and 10ppm for the birds level and 20 and 39ppm for the workers level, for ammonia and carbon monoxide, respectively. It was evident that the minimum ventilation systems were appropriately sized for the required minimum ambient air renovation, in respect to ventilation rates applied for the SVMN and SVMP systems, and with air velocity at levels that do not stress the chicks, including for the SVMNat. The three studied systems of minimum ventilation allowed the birds to externalize their productive performance, with values close to the ones considered satisfactory for all evaluated parameters, in accordance with the Brazilian aviculture standards.

scholarly journals Ambient Air and Hole Transport Layer Free Synthesis: Towards Low Cost CH3NH3PbI3Solar Cells

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Muhammad Imran Ahmed ◽  
Hareema Saleem ◽  
Ahmed Nawaz Khan ◽  
Amir Habib
Keyword(s):  
Graphene Oxide ◽  
Low Cost ◽  
Power Conversion ◽  
Ambient Air ◽  
Hole Transport ◽  
Transport Layer ◽  
Hole Transport Layer ◽  
Efficiency Increase ◽  
The Cost ◽  
Conversion Efficiencies

Perovskite absorbers have witnessed a remarkable efficiency increase in last couple of years. To meet the commercialization challenge, reduced cost and improved efficiency are the two critical factors. We report on a hole transport layer free device synthesized under ambient air conditions of high humidity of 50% using TiO2-graphene oxide nanocomposite as electron selective contact. The devices achieved a power conversion efficiency of 5.9%. We introduce a novel synthesis route for TiO2-graphene oxide (GO) composite allowing superior charge transport properties. Incorporation of GO in TiO2allows achieving higher power conversion efficiencies while working under ambient air conditions. Ambient air synthesis with hole transport free architecture has the potential to reduce the cost of this technology leading to commercial viability.

Sign in / Sign up

Export Citation Format

Share Document