Ventilation for Good Indoor Air Quality and Energy Efficiency

Numerical simulation application in occupational health studies: a review

Most occupational hazardous agents in workplaces should be evaluated and controlled. Different methods exist for identifying, evaluating and controlling these agents, such as numerical simulation tools. Numerical simulations can help experts to improve occupational health. Due to the importance and abilities of numerical simulations, this study divided occupational hazardous agents into 10 subgroups. These subgroups included air pollution, ventilation, respiratory airways, noise and vibration, lighting, radiation, ergonomics, fire and explosion, risk assessment and personal protective equipment. Recent research studies in each subgroup were then reviewed, and the codes and software used in simulations were determined. The results show that Fluent software and k-ϵ turbulence models are the most used in occupational health studies simulations. Today, different codes and software have been developed for simulation, and we suggest their use in occupational health studies.

Psychological Antecedents of the Intention to Open the Windows at Home and Exposure to a Ventilation Recommendation

Objective

The psychological antecedents of the intention to open the windows at home were explored through the Theory of Planned Behavior (TPB), supplemented with Habits regarding the behavior and contextual factors.

Design

A four-treatment design compared the effect of an exposure to a recommendation about home ventilation and the effect of one's own awareness odors (negative vs. positive) as a manipulated variable. Two quasi-experimental online surveys were conducted. A student sample (Study 1; N = 159) was replicated with a general population sample (Study 2; N = 338).

Results

Multiple hierarchical regression models were conducted (3 for Study 1; 3 for Study 2). The extended TPB model provided stable predictors explaining around sixty percent of variance. Attitude and Habits were the main predictors of window openings, Perceived Behavioral control as a secondary predictor. Perceived Behavioral Control contributed significatively with a negative interaction with Attitudes. Odor awareness decreased Intention to manually ventilate. No effect of recommendation was observed.

Discussion

The results filled a gap in the literature about the willingness to manually ventilate at home and efficacy of a recommendation. Practical implications argue that beyond a generic recommendation, effective messages need to be tailored regarding the determinants of willingness to open the windows.

Study on the Effect of an Intermittent Ventilation Strategy on Controlling Formaldehyde Concentrations in Office Rooms

Material emission and ventilation are two aspects influencing indoor air quality. In this study, a model predictive control (MPC) strategy is proposed for intermittent ventilation system in office buildings, to achieve a healthy indoor environment. The strategy is based on a dynamic model for predicting emissions of volatile organic compounds (VOCs) from materials. The key parameters of formaldehyde from panel furniture in the model are obtained by an improved C-history method and large-scale chamber experiments. The effectiveness of the determined key parameters is validated, which are then used to predict the formaldehyde concentration variation and the pre-ventilation time in a typical office room. In addition, the influence of some main factors (i.e., vacant time, loading ratio, air change rate) on the pre-ventilation time is analyzed. Results indicate that the pre-ventilation time of the intermittent ventilation system ranges from several minutes to several hours. The pre-ventilation time decreases exponentially with the increase in the vacant time, the air change rate, and with the decrease in the loading ratio. When the loading ratio of the furniture is 0.30 m2/m3 and the vacant time is 100 days, the required pre-ventilation time approaches zero. Results further reveal that an air change rate of 2 h−1 is the most effective means for rapid removal of indoor formaldehyde for the cases studied. The proposed strategy should be helpful for achieving effective indoor pollution control.

Internet of Things (IoT) Technologies for Managing Indoor Radon Risk Exposure: Applications, Opportunities, and Future Challenges

Radon gas is a harmful pollutant with a well-documented adverse influence on public health. In poorly ventilated environments, that are often prone to significant radon levels, studies indicate a known relationship between human radon exposure and lung cancer. Recent technology advances, notably on the Internet of Things (IoT) ecosystem, allow the integration of sensors, computing, and communication capabilities into low-cost and small-scale devices that can be used for implementing specific cyber-physical systems (CPS) for online and real-time radon management. These technologies are crucial for improving the overall building indoor air quality (IAQ), contributing toward the so-called cognitive buildings, where human-based control is tending to decline, and building management systems (BMS) are focused on balancing critical factors, such as energy efficiency, human radon exposure management, and user experience, to achieve a more transparent and harmonious integration between technology and the built environment. This work surveys recent IoT technologies for indoor radon exposure management (monitoring, assessment and mitigation), and discusses its main challenges and opportunities, by focusing on methods, techniques, and technologies to answer the following questions: (i) What technologies have been recently in use for radon exposure management; (ii) how they operate; (iii) what type of radon detection mechanisms do they use; and (iv) what type of system architectures, components, and communication technologies have been used to assist the referred technologies. This contribution is relevant to pave the way for designing more intelligent and sustainable systems that rely on IoT and Information and Communications Technology (ICT), to achieve an optimal balance between these two critical factors: human radon exposure management and building energy efficiency.

Improving the IAQ for Learning Efficiency with Indoor Plants in University Classrooms in Ajman, United Arab Emirates

The objective of this paper is to investigate the effect of improving indoor air quality with indoor plants. As a methodology, two target classrooms with the same size (120.64 m2) and 32 students per room were selected. Then, 48 areca palm pots (average leaf area of 300 cm2/pot) were placed, and the plant density was 14.68% of the floor area. Subjective assessment for general questions, learning motivation, perceived air quality, and SBS symptoms was conducted at 5 min after the class started and 5 min before the class ended. The results showed that the CO2 concentration by respiration of the students (average of 1873 ppm) exceeded the regulatory standard (1000 ppm), but the students did not recognize the indoor CO2 concentration. The increase in CO2 concentration in the classroom was lower in the case with plant placement (624 ppm) compared with the case without plant placement (about 1205 ppm). It was statistically proven that the CO2 concentration by respiration could be reduced by 50% if the indoor plant leaf area density were maintained at about 14.68% of the floor area. In the case with plant placement, the students perceived the indoor air quality to be 40% fresher and showed a 140% higher acceptability. Moreover, the complaining of SBS symptoms was improved by 108%, and the students’ perception that it was better to focus on learning increased by about 120%. As the awareness of sustainability increases, indoor plants will be more actively placed in the United Arab Emirates. Indoor plants not only provide a visual green effect to improve human comfort but also purify indoor air pollutants.

Evaluation of Integral Effect of Thermal Comfort, Air Quality and Draught Risk for Desks Equipped with Personalized Ventilation Systems

This work evaluates the integral effect of thermal comfort (TC), indoor air quality (IAQ) and Draught Risk (DR) for desks with four personalized ventilation (PV) systems. The numerical study, for winter and summer thermal conditions, considers a virtual chamber, a desk, four different PV systems, four seats and four virtual manikins. Two different PV configurations, two upper and two lower air terminal devices (ATD) with different distance between them are considered. In this study a coupling of numerical methodology, using one differential and two integral models, is used. The heating, ventilating and air conditioning (HVAC) system performance in this work is evaluated using DR and room air removal effectiveness (εDR) that is incorporated in an Air Distribution Index (ADI). This new index, named the Air Distribution Turbulence Index (ADTI), is used to consider simultaneously the TC, the IAQ, the DR and the effectiveness for heat removal (εTC), contaminant removal (εAQ) and room air removal (εDR). The results show that the ADI and ADTI, are generally higher for Case II than for Case I, increase when the inlet air velocity increases, are higher when the exit air is located at a height 1.2 m than when is located at 1.8 m, and are higher for summer conditions than for winter conditions. However, the values are higher for the ADI than ADTI.

Occupational exposure to pesticides and associated health effects among greenhouse farm workers

The number and production capacities of greenhouse farms have been increased across the globe, driven by an effort for addressing food security problems related to the rapid population growth and the effects of climate change. As a result, there was a large increase in the number of greenhouse farm workers who are typically involved in chemical preparations and pesticide sprayings, crop harvesting, and greenhouse maintenance activities. Considering the enclosed architecture of the greenhouse farm design and the frequent application of pesticides, the objective of this review was to characterize pesticide exposure levels and resultant health effects among greenhouse farm workers. While most health assessment studies were mainly based on self-reported symptoms, this review showed limited epidemiological and clinical studies on the assessment of the health effects of pesticide exposure on greenhouse workers' health. Reproductive disorders, respiratory symptoms, neurological symptoms, and skin irritations were the most reported health effects among greenhouse farm workers. Additionally, there were limited studies on respirable pesticide-borne fine and ultrafine particulate matters in greenhouse farms. Ventilation systems and indoor environmental conditions of greenhouse farms were not designed according to specifications of the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). Among recommendations provided, long-term exposure assessments of pesticide effects on children born by greenhouse farm workers should be considered in future research. Also, compliance with ASHRAE indoor ventilation and environmental standards will be very important in reducing pesticide exposure and health effects among greenhouse farm workers.

Assessment of environmental and ergonomic hazard associated to printing and photocopying: a review

"Knowledge is power" and distribution of knowledge is fueled by printing and photocopying industry. Even as printing and photocopying industry have revolutionized the availability of documents and perceptible image quickly at extremely inexpensive and affordable cost, the boon of its revolution has turned into a bane by irresponsible, uncontrolled and extensive use, causing irreversible degradation to not only ecosystem by continuous release of ozone and other volatile organic compounds (VOCs) but also the health of workers occupationally exposed to it. Indoor ozone level due to emission from different photocopying equipment's increases drastically and the condition of other air quality parameters are not different. This situation is particularly sedate in extremely sensitive educational and research industry where sharing of knowledge is extremely important to meet the demands. This work is an attempt to catalogue all the environmental as well as health impacts of printing or photocopying. It has been observed that printing/photocopying operation is a significant factor contributing to indoor air quality degradation, which includes increase in concentration of ozone, VOCs, semi-volatile organic compounds (SVOCs) and heavy metals such as cadmium, selenium, arsenic, zinc, nickel, and other pollutants from photocopy machines. The outcome of this study will empower the manufactures with information regarding ozone and other significant emission, so that their impact can be reduced.

Experimental Investigation of Ventilation Performance of Different Air Distribution Systems in an Office Environment—Heating Mode

A vital requirement for all-air ventilation systems are their functionality to operate both in cooling and heating mode. This article experimentally investigates two newly designed air distribution systems, corner impinging jet (CIJV) and hybrid displacement ventilation (HDV) in comparison against a mixing type air distribution system. These three different systems are examined and compared to one another to evaluate their performance based on local thermal comfort and ventilation effectiveness when operating in heating mode. The evaluated test room is an office environment with two workstations. One of the office walls, which has three windows, faces a cold climate chamber. The results show that CIJV and HDV perform similar to a mixing ventilation in terms of ventilation effectiveness close to the workstations. As for local thermal comfort evaluation, the results show a small advantage for CIJV in the occupied zone. Comparing C2-CIJV to C2-CMV the average draught rate (DR) in the occupied zone is 0.3% for C2-CIJV and 5.3% for C2-CMV with the highest difference reaching as high as 10% at the height of 1.7 m. The results indicate that these systems can perform as well as mixing ventilation when used in offices that require moderate heating. The results also show that downdraught from the windows greatly impacts on the overall airflow and temperature pattern in the room.

The Effect of Ventilation Strategies on Indoor Air Quality and Energy Consumptions in Classrooms

Most of the school buildings in Italy are high energy-demanding buildings with no ad-hoc ventilation systems (i.e., naturally-ventilated buildings). Therefore, reducing the heat losses of schools represent the main aspect to be dealt with. Nonetheless, the indoor air quality of the building should be simultaneously considered. Indeed, to date, energy consumptions and air quality are considered as incompatible aspects especially in naturally-ventilated buildings. The aim of the present paper is to evaluate the effect of different ventilation and airing strategies on both indoor air quality and energy consumptions in high energy-demanding naturally-ventilated classrooms. To this purpose, an Italian test-classroom, characterized in terms of air permeability and thermophysical parameters of the envelope, was investigated by means of experimental analyses and simulations through CO2 mass balance equation during the heating season. The air quality was assessed in terms of indoor CO2 concentrations whereas the energy consumptions were evaluated through the asset rating approach. Results clearly report that not adequate indoor CO2 concentrations are measured in the classroom for free-running ventilation scenarios even in low densely populated conditions (2.2 m2 person−1), whereas scheduled airing procedures can reduce the indoor CO2 levels at the cost of higher energy need for ventilation. In particular, when airing periods leading to the air exchange rate required by standards are adopted, the CO2 concentration can decrease to values lower than 1000 ppm, but the ventilation losses increase up to 36% of the overall energy need for space heating of the classroom. On the contrary, when the same air exchange rate is applied through mechanical ventilation systems equipped with heat recovery units, the ventilation energy loss contribution decreases to 5% and the overall energy saving results higher than 30%. Such energy-saving was found even higher for occupancy scenarios characterized by more densely populated conditions of the classroom typically occurring in Italian classrooms.

Multiple Benefits through Smart Home Energy Management Solutions—A Simulation-Based Case Study of a Single-Family-House in Algeria and Germany

From both global and local perspectives, there are strong reasons to promote energy efficiency. These reasons have prompted leaders in the European Union (EU) and countries of the Middle East and North Africa (MENA) to adopt policies to move their citizenry toward more efficient energy consumption. Energy efficiency policy is typically framed at the national, or transnational level. Policy makers then aim to incentivize microeconomic actors to align their decisions with macroeconomic policy. We suggest another path towards greater energy efficiency: Highlighting individual benefits at microeconomic level. By simulating lighting, heating and cooling operations in a model single-family home equipped with modest automation, we show that individual actors can be led to pursue energy efficiency out of enlightened self-interest. We apply simple-to-use, easily, scalable impact indicators that can be made available to homeowners and serve as intrinsic economic, environmental and social motivators for pursuing energy efficiency. The indicators reveal tangible homeowner benefits realizable under both the market-based pricing structure for energy in Germany and the state-subsidized pricing structure in Algeria. Benefits accrue under both the continental climate regime of Germany and the Mediterranean regime of Algeria, notably in the case that cooling energy needs are considered. Our findings show that smart home technology provides an attractive path for advancing energy efficiency goals. The indicators we assemble can help policy makers both to promote tangible benefits of energy efficiency to individual homeowners, and to identify those investments of public funds that best support individual pursuit of national and transnational energy goals.

Experimental Investigation of the Ventilation Performance of Different Air Distribution Systems in an Office Environment—Cooling Mode

The performance of a newly designed corner impinging jet air distribution method with an equilateral triangle cross section was evaluated experimentally and compared to that of two more traditional methods (mixing and displacement ventilation). At nine evenly chosen positions with four standard vertical points, air velocity, turbulence intensity, temperature, and tracer gas decay measurements were conducted for all systems. The results show that the new method behaves as a displacement ventilation system, with high air change effectiveness and stratified flow pattern and temperature field. Both local air change effectiveness and air exchange effectiveness of the corner impinging jet showed high quality and promising results, which is a good indicator of ventilation effectiveness. The results also indicate that there is a possibility to slightly lower the airflow rates for the new air distribution system, while still meeting the requirements for thermal comfort and indoor air quality, thereby reducing fan energy usage. The draught rate was also lower for corner impinging jet compared to the other tested air distribution methods. The findings of this research show that the corner impinging jet method can be used for office ventilation.

Sick building syndrome and associated risk factors among the population of Gondar town, northwest Ethiopia

BACKGROUND

Sick building syndrome (SBS) consists of a group of mucosal, skin, and general symptoms temporally related to residential and office buildings of unclear causes. These symptoms are common in the general population. However, SBS symptoms and their contributing factors are poorly understood, and the community associates it with bad sprits. This community-based cross-sectional study was, therefore, conducted to assess the prevalence and associated factors of SBS in Gondar town.

METHODS

A community-based cross-sectional study was conducted from March to April 2017. A total of 3405 study subjects were included using multistage and systematic random sampling techniques. A structured questionnaire and observational checklists were used to collect data. SBS was assessed by 24 building-related symptoms and confirmed by five SBS confirmation criteria. Multivariable binary logistic regression analysis was used to identify factors associated with SBS on the basis of adjusted odds ratio (AOR) with 95% confidence interval (CI) and p < 0.05. The Hosmer and Lemeshow goodness of fit test was used to check model fitness, and variance inflation factor (VIF) was also used to test interactions between variables.

RESULTS

The prevalence of SBS in Gondar town was 21.7% (95% CI = 20.3-23.0%). Of this, the mucosal symptoms account for 64%, the general symptoms account for 54%, and the skin symptoms account for 10%. From study participants who reported SBS symptoms, 44% had more than one symptom. Headache (15.7%), asthma (8.3%), rhinitis (8.0%), and dizziness (7.5%) were the commonest reported symptoms. SBS was significantly associated with fungal growth in the building [AOR = 1.25, 95% CI = (1.05, 1.49)], unclean building [AOR = 1.26, 95% CI = (1.03, 1.55)], houses with no functional windows [AOR = 1.35, 95% CI = (1.12, 1.63)], houses with no fan [AOR = 1.90, 95% CI = (1.22, 2.96)], utilization of charcoal as a cooking energy source [AOR = 1.40, 95% CI = (1.02, 1.91)], cooking inside the living quarters [AOR = 1.31, 95% CI = (1.09, 1.58)], and incensing and joss stick use [AOR = 1.48, 95% CI = (1.23, 1.77)].

CONCLUSION

The prevalence of SBS in Gondar town was high, and significant proportion of the population had more than one SBS symptom. Headache, asthma, rhinitis, and dizziness were the commonest reported SBS symptoms. Fungal growth, cleanliness of the building, availability of functional windows, availability of fan in the living quarters, using charcoal as a cooking energy source, cooking inside the quarters, and incensing habit or joss stick use were identified as factors associated with SBS. Improving the sanitation of the living environment and housekeeping practices of the occupants is useful to minimize the prevalence of SBS.