Exhaled Carbon Dioxide as a Physiological Source of Deterioration of Indoor Air Quality in Non-Industrial Environments: Influence of Air Temperature

People are the main reason for the deterioration of indoor air quality (IAQ) due to the continuous physiological metabolism processes in their bodies, including respiration. We present results from an investigation of the influence of indoor air temperature on the concentration of exhaled carbon dioxide (CO2). The investigation was preconditioned by previous findings on the effect of air temperature on human metabolism. However, our literature survey showed a lack of studies on the influence of the indoor air temperature on the exhaled CO2 (or metabolic CO2), which leads to the novelty of our results. Our experiments had two phases: measurement in a university classroom with an installed heating, ventilation, and air-conditioning (HVAC) system during regular classes and measurement in a specially designed small climate chamber, where the time variations of the CO2 concentrations, together with some physiological parameters, were measured. Two indoor air temperatures were set: 23 °C and 27 °C. The results obtained and their respective analyses show the strong effect of the two air temperatures on the CO2 concentration due to exhalation. In the classroom, the CO2 concentration at 27 °C was higher by 6.2% than at 23 °C. In the climate chamber, the CO2 concentration at 27 °C was higher by 9.6% than at 23 °C. Physiological parameters (oxygen saturation pressure, pulse rate, end-tidal CO2, and respiration rate) and their dependence on the air temperature were also measured in the climate chamber, establishing an effect of the temperature on the pulse rate.

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Mitigation Strategies for Overheating and High Carbon Dioxide Concentration within Institutional Buildings: A Case Study in Toronto, Canada

Buildings ◽

10.3390/buildings10070124 ◽

2020 ◽

Vol 10 (7) ◽

pp. 124 ◽

Cited By ~ 1

Author(s):

Claire Tam ◽

Yuqing Zhao ◽

Zaiyi Liao ◽

Lian Zhao

Keyword(s):

Carbon Dioxide ◽

Air Quality ◽

Indoor Air Quality ◽

Air Temperature ◽

Indoor Air ◽

Indoor Environment ◽

Thermal Conditions ◽

Co2 Concentration ◽

Hvac System

Indoor air quality and thermal conditions are important considerations when designing indoor spaces to ensure occupant health, satisfaction, and productivity. Carbon dioxide (CO2) concentration and indoor air temperature are two measurable parameters to assess air quality and thermal conditions within a space. Occupants are progressively affected by the indoor environment as the time spent indoors prolongs. Specifically, there is an interest in carrying out investigations on the indoor environment through surveying existing Heating, Ventilation, Air Conditioning (HVAC) system operations in classrooms. Indoor air temperature and CO2 concentration in multiple lecture halls in Toronto, Canada were monitored; observations consistently show high indoor air temperature (overheating) and high CO2 concentration. One classroom is chosen as a representative case study for this paper. The results verify a strong correlation between the number of occupants and the increase in air temperature and CO2 concentration. Building Energy Simulation (BES) is used to investigate the causes of discomfort in the classroom, and to identify methods for regulating the temperature and CO2 concentration. This paper proposes retro-commissioning strategies that could be implemented in institutional buildings; specifically, the increase of outdoor airflow rate and the addition of occupancy-based pre-active HVAC system control. The proposed retrofit cases reduce the measured overheating in the classrooms by 2-3 °C (indoor temperature should be below 23 °C) and maintain CO2 concentration under 900 ppm (the CO2 threshold is 1000 ppm), showing promising improvements to a classroom’s thermal condition and indoor air quality.

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DESIGNING A SMALL CLIMATE CHAMBER TO CHARACTERIZE PEOPLE AS A SOURCE OF DETERIORATION OF INDOOR AIR QUALITY BY RESPIRATION

CBU International Conference Proceedings ◽

10.12955/cbup.v7.1484 ◽

2019 ◽

Vol 7 ◽

pp. 954-959 ◽

Cited By ~ 1

Author(s):

Detelin Ganchev Markov ◽

Sergey Mijorski ◽

Peter Stankov ◽

Iskra Simova ◽

Radositna A. Angelova ◽

...

Keyword(s):

Carbon Dioxide ◽

Water Vapor ◽

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Carbon Dioxide Concentration ◽

Air Distribution ◽

Vapor Concentration ◽

Cfd Simulations ◽

Climate Chamber

: People are one of the sources for deterioration of the indoor air quality. They worsen indoor air quality by their presence (respiration, bio-effluents), activities and habits. Through respiration, people decrease the oxygen concentration in the air of the occupied space and increase carbon dioxide and water vapor concentration in the indoor air as well as its temperature. The goal of the AIRMEN project is to find out if the rate of consumption of oxygen and emission of carbon dioxide (and water vapor) by people depends on the indoor air temperature as well as carbon dioxide concentration in the inhaled air. In order to achieve this goal a small climate chamber must be designed and constructed which allows for controlling and measuring both inflow and exposure parameters as well as for measuring outflow parameters. The principal goal of this paper is to present some important details, obtained by CFD simulations, from the design process of the climate chamber which precondition the air distribution in the chamber and hence the exposure parameters.

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Method for Estimation of CO2 Gains from Persons in Builidings

Proceedings ◽

10.3390/proceedings2201309 ◽

2018 ◽

Vol 2 (20) ◽

pp. 1309 ◽

Cited By ~ 2

Author(s):

Antonio Rodero ◽

Dorota Anna Krawczyk

Keyword(s):

Carbon Dioxide ◽

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Carbon Dioxide Concentration ◽

Co2 Concentration ◽

Males And Females ◽

Sources Of Co2

Carbon dioxide concentration is an important parameter to know Indoor Air Quality of a building. One of the most important sources of CO2 in poor ventilated building is human activity. This work presents a method for experimental determination of human CO2 generation rate based on measuring of time evolution of indoor CO2 concentration. The method is applied to 5 rooms of an educational building from Bialystok (Poland). Similar carbon dioxide gains were obtained in all rooms, around 0.0046 L/s, which correspond to theoretical CO2 generation rates of a sedentary activity for persons, males and females, between 21–30 years old, characteristics of occupants of analyzed rooms.

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Practical Impact of the COVID-19 Pandemic on Indoor Air Quality and Thermal Comfort in Kindergartens. A Case Study of Slovenia

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18189712 ◽

2021 ◽

Vol 18 (18) ◽

pp. 9712

Author(s):

Vesna Lovec ◽

Miroslav Premrov ◽

Vesna Žegarac Leskovar

Keyword(s):

Carbon Dioxide ◽

Air Quality ◽

Thermal Comfort ◽

Indoor Air Quality ◽

Air Temperature ◽

Indoor Air ◽

Carbon Dioxide Concentration ◽

Building Stock ◽

Practical Impact

The experimental monitoring of carbon dioxide concentration was carried out in kindergartens in Slovenia, together with indoor air temperature and relative humidity, before and during the COVID-19 pandemic. The aim of the research was to estimate the practical impact of the pandemic on indoor air quality and thermal comfort. The case study sample included buildings with different architectural typology, which are predominantly present in the building stock of Slovenia. The monitoring process lasted for 125 days before and during the COVID-19 pandemic. The results have shown a better indoor air quality in kindergartens during the pandemic, mostly due to ventilation protocols and almost imperceptibly changed indoor air temperature. The COVID-19 pandemic affected air quality in kindergarten classrooms in Slovenia by reducing the average carbon dioxide concentration when children were present in classrooms by 30%.

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The Indoor Air Quality in Laboratory Buildings. A Case Study in Integrated Laboratory of UIN Sunan Ampel Surabaya

KnE Social Sciences ◽

10.18502/kss.v3i21.5018 ◽

2019 ◽

Author(s):

Widya Nilandita ◽

Ida Munfarida ◽

M Ratodi ◽

Dyah Ratri Nurmaningsih ◽

Dedy Suprayogi

Keyword(s):

Carbon Dioxide ◽

Sustainable Development ◽

Air Quality ◽

Relative Humidity ◽

Thermal Comfort ◽

Indoor Air Quality ◽

Indoor Air ◽

Co2 Concentration ◽

Cross Sectional ◽

Carbon Dioxide Co2

Indoor Air Quality (IAQ) is one of the critical issues in sustainable development related to human health as the primary goal. Sustainable development should address potential human exposure to pollutants and health impacts. The laboratory, as educational support in the university, has specific contaminants, but studies on IAQ and thermal comfort in the laboratory have not been studied. IAQ and thermal comfort in a laboratory are essential as they can affect the work and health of the researchers and staffs. The purpose of this study is to analyze indoor air quality in an integrated laboratory of UIN Sunan Ampel Surabaya. This research is a cross-sectional study. Data analysis was done by a quantitative descriptive method. The air quality parameters in the laboratory were temperature, relative humidity, and carbon dioxide (CO2) concentration. All settings compared to the air quality standard. The analysis on carbon dioxide (CO2) concentration, relative humidity (%RH), temperature (∘C) has shown that the indoor air does not exceed the standard according to ASHRAE standard and Health Ministry Regulation with the maximum concentration was 444,3 ppm. The fan installation and increased air filter to controlled humidity are the option to improve the indoor air quality.

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Letter to the editor: Ventilation is key, open a window

10.31219/osf.io/7rczy ◽

2020 ◽

Author(s):

Nisha Patel ◽

Ciara Docherty ◽

James R Allison ◽

Graham Walton ◽

Ben Cole ◽

...

Keyword(s):

Carbon Dioxide ◽

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Co2 Concentration ◽

Transmission Probability ◽

Respiratory Protection ◽

Infection Transmission ◽

Short Period ◽

Co2 Levels

Dear Sir, We read with interest a recent article which modelled the risk to dental health care workers of various airborne pathogens [1]. This paper used Carbon Dioxide (CO2) concentration as an indicator of air quality and ventilation, reasoning that CO2 ;levels provide a measure of exposure to exhaled breath [2]. Reassuringly, with high indoor air quality, and a filtering facepiece-2 (FFP2) mask, infection transmission probability was estimated at 0% for severe acute respiratory syndrome coronavirus (SARS-CoV). CO2 concentration (i.e. air quality and ventilation) had the biggest influence on estimated transmission risk, much more so than respiratory protection from masks. With “medium” air quality the estimated transmission probability remained over 20% regardless of respiratory protection (masks) and patient infectivity. It should be noted that these data were based on SARS-CoV-1, but SARS-CoV-2 is expected to behave similarly.Using CO2 concentration is a useful, quick and inexpensive measure to assess air quality in indoor spaces and may be of use to readers. High air quality is defined as < 800 ppm CO2 [3]. We used a calibrated CO2 meter (Extech CO240; Nashua, NH, USA; £200) to assess four indoor environments within Newcastle dental school and hospital, with known air exchange rates. Two people sat (physically distanced) in each space for 30 minutes, allowing CO2 to accumulate, before leaving the area whilst measurement continued. We found that the increase in CO2 was minimal in most environments, with air quality remaining high (i.e. < 800 ppm CO2). In one unventilated, windowless surgery, levels did reach medium quality for a short period. This highlights the potential value of this simple technique in identifying areas with poorer ventilation. We next repeated the measurements with any windows open, and found that air quality and ventilation improved further; this was close to CO2 levels found outdoors. In conclusion, measuring CO2 concentration may be a useful way to measure indoor air quality and opening a window is a powerful and simple way to improve ventilation. Nisha Patel, Ciara Docherty, James Allison, Graham Walton, Ben Cole, Justin Durham, Nick Jakubovics and Richard HollidaySchool of Dental Sciences, Newcastle UniversityNewcastle Hospitals NHS Foundation TrustCorrespondence to [email protected] C, Awad SF, Volgenant CM, Crielaard W, Laheij AM, de Soet JJ. Modeling of the Transmission of Coronaviruses, Measles Virus, Influenza Virus, Mycobacterium tuberculosis, and Legionella pneumophila in Dental Clinics. J Dent Res 2020; 2:0022034520940288. DOI: https://doi.org/10.1177/0022034520940288. 2.Rudnick SN, Milton DK. Risk of indoor airborne infection transmission estimated from carbon dioxide concentration. Indoor air. 2003; 13(3): 237-45. DOI: https://doi.org/10.1034/j.1600-0668.2003.00189.x3.Kukadia V, Upton S. Ensuring good indoor air quality in buildings. BRE Group. Ensuring Good Indoor Air Quality in Buildings. 2019. Available at https://www.bregroup.com/bretrust/wp-content/uploads/sites/12/2019/03/Ensuring-Good-IAQ-in-Buildings-Trust-report_compressed-2.pdf (accessed July 2020).

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Effects of Climatic Conditions, Season and Environmental Factors on CO2 Concentrations in Naturally Ventilated Primary Schools in Chile

Sustainability ◽

10.3390/su13084139 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4139

Author(s):

Muriel Diaz ◽

Mario Cools ◽

Maureen Trebilcock ◽

Beatriz Piderit-Moreno ◽

Shady Attia

Keyword(s):

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Primary Schools ◽

Co2 Concentration ◽

Building Design ◽

Climatic Conditions ◽

Indoor Environmental Quality ◽

Co2 Concentrations ◽

The Impact

Between the ages of 6 and 18, children spend between 30 and 42 h a week at school, mostly indoors, where indoor environmental quality is usually deficient and does not favor learning. The difficulty of delivering indoor air quality (IAQ) in learning facilities is related to high occupancy rates and low interaction levels with windows. In non-industrialized countries, as in the cases presented, most classrooms have no mechanical ventilation, due to energy poverty and lack of normative requirements. This fact heavily impacts the indoor air quality and students’ learning outcomes. The aim of the paper is to identify the factors that determine acceptable CO2 concentrations. Therefore, it studies air quality in free-running and naturally ventilated primary schools in Chile, aiming to identify the impact of contextual, occupant, and building design factors, using CO2 concentration as a proxy for IAQ. The monitoring of CO2, temperature, and humidity revealed that indoor air CO2 concentration is above 1400 ppm most of the time, with peaks of 5000 ppm during the day, especially in winter. The statistical analysis indicates that CO2 is dependent on climate, seasonality, and indoor temperature, while it is independent of outside temperature in heated classrooms. The odds of having acceptable concentrations of CO2 are bigger when indoor temperatures are high, and there is a need to ventilate for cooling.

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Transient Effects of Different Ventilation Methods on Car Indoor Air Quality

Studies in Engineering and Technology ◽

10.11114/set.v2i1.891 ◽

2015 ◽

Vol 2 (1) ◽

pp. 70 ◽

Cited By ~ 2

Author(s):

Feng-Chyi Duh

Keyword(s):

Carbon Dioxide ◽

Air Quality ◽

Indoor Air Quality ◽

Indoor Air ◽

Air Conditioning ◽

Heat Index ◽

Transient Effects ◽

Air Conditioning System ◽

Carbon Dioxide Concentrations ◽

Volatile Organic

This study investigated transient effects on the air quality of parked cars and moving cars with and without operating air conditioning. Carbon dioxide, carbon monoxide, volatile organic compounds, and formaldehyde concentrations were measured for comparative analysis. The results showed that simply changing the air conditioning system from internal circulation to external circulation to introduce air from outside reduces carbon dioxide concentrations by more than 50%, volatile organic compound concentrations by more than 77%, and the heat index from 0.1℃/min to less than 0.05 ℃/min. In order to conserve energy and improve car indoor air quality, this study can serve as a reference on healthy car environments.

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