scholarly journals Indoor Air Quality Prior to and Following School Building Renovation in a Mid-Atlantic School District

2021 ◽  
Vol 18 (22) ◽  
pp. 12149
Author(s):  
Sandra E. Zaeh ◽  
Kirsten Koehler ◽  
Michelle N. Eakin ◽  
Christopher Wohn ◽  
Ike Diibor ◽  
...  
Keyword(s):  
Public Schools ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Mixed Models ◽  
Indoor Environment ◽  
Linear Mixed Models ◽  
School Building ◽  
School Renovation ◽  
Indoor Pm2.5

Children spend the majority of their time indoors, and a substantial portion of this time in the school environment. Air pollution has been shown to adversely impact lung development and has effects that extend beyond respiratory health. The goal of this study was to evaluate the indoor environment in public schools in the context of an ongoing urban renovation program to investigate the impact of school building renovation and replacement on indoor air quality. Indoor air quality (CO2, PM2.5, CO, and temperature) was assessed for two weeks during fall, winter, and spring seasons in 29 urban public schools between December 2015 and March 2020. Seven schools had pre- and post-renovation data available. Linear mixed models were used to examine changes in air quality outcomes by renovation status in the seven schools with pre- and post-renovation data. Prior to renovation, indoor CO measurements were within World Health Organization (WHO) guidelines, and indoor PM2.5 measurements rarely exceeded them. Within the seven schools with pre- and post-renovation data, over 30% of indoor CO2 measurements and over 50% of indoor temperatures exceeded recommended guidelines from the American Society of Heating, Refrigerating, and Air Conditioning Engineers. Following renovation, 10% of indoor CO2 measurements and 28% of indoor temperatures fell outside of the recommended ranges. Linear mixed models showed significant improvement in CO2, indoor PM2.5, and CO following school renovation. Even among schools that generally met recommendations on key guidelines, school renovation improved the indoor air quality. Our findings suggest that school renovation may benefit communities of children, particularly those in low-income areas with aging school infrastructure, through improvements in the indoor environment.

Computational Modeling of Particulate Pollutant Transport in a Ventilated Room in the Presence of Two Heated Breathing and Rotating Manikins

2017 ◽  
Author(s):  
Seyed Ali Keshavarz ◽  
Mazyar Salmanzadeh ◽  
Goodarz Ahmadi
Keyword(s):  
Air Quality ◽  
Computational Modeling ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Rotational Motion ◽  
Indoor Environment ◽  
Ventilation System ◽  
Thermal Plume ◽  
Displacement Ventilation ◽  
Simulation Results

Recently, attention has been given to indoor air quality due to its serious health concerns. Clearly the dispersion of pollutant is directly affected by the airflow patterns. The airflow in indoor environment is the results of a combination of several factors. In the present study, the effects of thermal plume and respiration on the indoor air quality in a ventilated cubicle were investigated using an unsteady computational modeling approach. The person-to-person contaminant transports in a ventilated room with mixing and displacement ventilation systems were studied. The effects of rotational motion of the heated manikins were also analyzed. Simulation results showed that in the cases which rotational motion was included, the human thermal plume and associated particle transport were significantly distorted. The distortion was more noticeable for the displacement ventilation system. Also it was found that the displacement ventilation system lowered the risk of person-to-person transmission in an office space in comparison with the mixing ventilation system. On the other hand the mixing system was shown to be more effective compared to the displacement ventilation in removing the particles and pollutant that entered the room through the inlet air diffuser.

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

Buildings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 124 ◽  
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.

scholarly journals Revised Finnish classification of indoor climate 2018

2019 ◽  
Vol 111 ◽  
pp. 02017 ◽  
Author(s):  
Mervi Ahola ◽  
Jorma Säteri ◽  
Laura Sariola
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Indoor Environment ◽  
Building Materials ◽  
Fine Particles ◽  
Indoor Climate ◽  
Environmental Classification ◽  
Target Values

The Finnish Society of Indoor Air Quality and Climate (FiSIAQ) introduced a Classification of Indoor Climate, Construction Cleanliness, and Finishing Materials in 1995. The Classification of Indoor Climate has been revised to meet the new Decree on indoor air quality and ventilation, European standards and experience from users of the classification. The most significant change is that target values for concentration and the in/out ratio of fine particles have been added. Other adjustments have been made to ensure good indoor environment and energy efficiency, but with reasonable investments. The criteria for emissions from building material and furniture were also updated. The Building Information Foundation RTS sr has run the M1-labelling of building products since 1996. The voluntary approach has been proven to improve the IAQ in new buildings and to reduce emissions from building materials. The Classification of Indoor Environment 2018 is integrated part of the new RTS Environmental Classification system.

Positive pressure effect on moisture performance in a school building

2019 ◽  
Vol 43 (2) ◽  
pp. 121-142
Author(s):  
Andrea Ferrantelli ◽  
Camilla Vornanen-Winqvist ◽  
Milla Mattila ◽  
Heidi Salonen ◽  
Jarek Kurnitski
Keyword(s):  
Air Quality ◽  
Moisture Content ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Moisture Transfer ◽  
Building Envelope ◽  
Positive Pressure ◽  
School Building ◽  
Negative Effects ◽  
Moisture Performance

Moisture excess in buildings constitutes a complex problem affecting indoor air quality, energy consumption and the lifetime of the building envelope. We investigate the effect on moisture transfer in structures as a positive pressure is applied inside the enclosure. It is found that, contrary to established belief, the positive pressure does not induce any negative effects on the structures’ moisture content in normally ventilated classrooms, even with high occupancy. Our case study consists of a school building in Finland, subject to temperature and relative humidity measurements after a small (5–7 Pa) positive pressure was realized through ventilation control. We first address analytically the moisture excess generated inside the classrooms for 14 days, using dynamical balance equations that account for both ventilation effects and occupants’ moisture release in the environment. It is found that the average moisture excess is very small, largely below 1 g/m3, even for ventilation rates that are half the design value. We also examine the moisture performance of the envelope, by addressing the moisture migration at upper and lower joints of the external walls for both measured and design values of the indoor absolute humidity (AH). A coupled numerical model of diffusion and convection shows that moisture accumulation in the envelope and the according stresses are negligible for any realistic AH values. This result is in agreement with field measurements at the school. In conclusion, it seems that applying a small overpressure in a well-ventilated school building during a standard service period resulted in no accumulation inside the external walls, even at high occupancy and with low ventilation. Remarkably, it slightly dried out the moisture content in structures under actual occupancy conditions. The positive pressure has accordingly no negative effects on moisture performance, and is capable to guarantee a good indoor air quality as well.

scholarly journals Indoor Air Quality Enhancement Performance of Liquid Desiccant and Evaporative Cooling-Assisted Air Conditioning Systems

2019 ◽  
Vol 11 (4) ◽  
pp. 1036 ◽  
Author(s):  
Beom-Jun Kim ◽  
Junseok Park ◽  
Jae-Weon Jeong
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Reference System ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Quality Enhancement ◽  
Liquid Desiccant ◽  
Air Conditioning Systems ◽  
Indoor Pm2.5

The main objective of this study is to investigate the indoor air quality enhancement performance of two different liquid desiccant and evaporative cooling-assisted air conditioning systems, such as the variable air volume (VAV) system with the desiccant-enhanced evaporative (DEVap) cooler, and the liquid desiccant system with an indirect and direct evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS), compared with the conventional VAV system. The transient simulations of concentration variations of carbon dioxide (CO2), coarse particles, and fine particles (PM10 and PM2.5) in a model office space served by each system were performed using validated system models that were found in the literature. Based on the hourly thermal loads of the model space predicted by the TRNSYS 18 program, each air conditioning system was operated virtually using a commercial equation solver program (EES). The results indicated that the LD-IDECOAS provided the lowest annual indoor CO2 concentration among all the systems considered in this research, while the VAV system with DEVap cooler exceeded the threshold concentration (i.e., 1000 ppm) during the cooling season (i.e., July, August, and September). For the indoor particulate contaminant concentrations, both liquid desiccant and evaporative cooling-assisted air conditioning systems indicated lower indoor PM2.5 and PM10 concentrations compared with the reference system. The LD-IDECOAS and the VAV with a DEVap cooler demonstrated 33.3% and 23.5% lower annual accumulated indoor PM10 concentrations than the reference system, respectively. Similarly, the annual accumulated indoor PM2.5 concentration was reduced by 16% using the LD-IDECOAS and 17.1% using the VAV with DEVap cooler.

scholarly journals INVESTIGATING INDOOR AIR QUALITY AND THERMAL COMFORT USING DIFFERENT VENTILATION SYSTEMS UNDER IRAQI CLIMATE

2018 ◽  
Vol 18 (3) ◽  
pp. 422-435
Author(s):  
Ala'a A Mahdi ◽  
Sara Abbas
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Indoor Environment ◽  
Simulation Models ◽  
Air Distribution ◽  
Airflow Rate ◽  
Computational Fluid Dynamics Cfd ◽  
Occupied Zone ◽  
Ventilation Systems

Computational Fluid Dynamics (CFD) of indoor environment as well as qualityconsiderations are important element in the study of energy consumption, thermal comfortand indoor air quality in buildings. This paper investigate a comparison work betweenimpinging jet, displacement, and mixing ventilation systems for an isothermal and nonisothermalventilated room for Indoor Air Quality (IAQ) and thermal human comfort underIraqi climate. For IJV system, draught discomfort is the issue of most concern since itsupplies cooled air directly to the occupied zone. This study investigated a number of factorsinfluencing draught discomfort and temperature stratification in an office environment. Theconsidered factors, supply airflow rate and supply air temperature. RNG K-? turbulencemodel was used with the turbulent flow. The second aspect included numerical analyses byadopting ANSYS FLUENT15 code to generate simulation models. A square shaped airsupply device was used with [0.1 times room height (h)] outlet terminal height from the footlevel end. The IJV system proved more efficient than displacement and mixing ventilationsystems. The Air Distribution Performance Index (ADPI) obtained for an isothermal andnon-isothermal ventilated room adopting IJV system gave best values (0.80, 0.83)respectively compared with the other two ventilation systems.

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