Office Ventilation Research Articles

Generic geometrical parametric study of wind-driven natural ventilation to improve indoor air quality and air exchange in offices

Indoor air quality significantly enhances employee productivity and well-being in offices. Existing models and guidelines emphasize wind-driven natural ventilation for air exchange and thermal comfort but often overlook detailed airflow patterns. Understanding airflow dynamics is crucial for designing healthy offices, and offering insights into air exchange processes. This information is particularly valuable in mitigating the impact of CO2 and droplet release from multiple occupants, contributing to the creation of healthier office environments. This study, thus, employs a validated CFD model to investigate the impact of geometrical parameters on wind-driven ventilation in offices. With about 150 cases representing alterations in parameters for single-sided (SV) and double-sided (DV) ventilation, a sensitivity analysis identifies key contributors to airflow patterns. Eventually, while five major categories for the airflow patterns can be identified in the DV cases (i.e., (1) without a weak zone (WZ), (2) with a dominant WZ, (3) with a WZ on bottom side, (4) with a WZ on upper side, and (5) with two WZs on upper and bottom sides), a generic airflow pattern can be barely seen in the SV cases. Moreover, in the DV cases, velocity magnitude is crucial for classification of the outputs. The leeward window geometry influences DV natural ventilation more than the windward window. Furthermore, the room dimensions impact ACH more than SF6 concentration and velocity. In the SV cases, location of the infected occupant dominates air changes per hour (ACH), and theta significantly impacts average velocity in contrast to the DV scenarios.

Modernization of an automated office ventilation control system using artificial intelligence

Modernization of an automated office ventilation control system using artificial intelligence

The establishment of design criteria for precision ventilation in open-plan offices

Precision ventilation is used in open-plan offices to establish micro-climate zones according to the metabolic requirements of its occupants. The aim of this study is to determine design criteria and highlight the opportunities and limitations for precision ventilation in large-scale offices. The simulations and experiments were conducted under steady state conditions with fixed airflow from all active chilled beams (ACBs) and constant room temperatures. A temperature difference of 3.5K was maintained between supply and room air in all cases with and without occupants. Results showed that precision ventilation can simultaneously establish low-level (<0.15 m/s), medium-level (<0.45 m/s), and high-level (<0.65 m/s) air velocity zones in the same shared office space such that occupants with different metabolic rates had Predicted Mean Vote (PMV) values maintained within the acceptable limit. The establishment of a single air velocity zone in an open-plan office layout without influencing air velocities of other zones was achieved by lowering the airflow rates of two ACBs by 35%. The vertical and horizontal temperature uniformity was maintained with this precision ventilation system with draught rates of less than 20% for occupants with normal metabolic rates. Comparative analysis using precision ventilation with and without occupants showed that targeted air velocity distribution in the room can be negatively influenced by the absence of any heat sources in any zone. An annual energy saving of up to 15% was achieved by raising the cooling setpoint temperature from 23 °C to 25 °C.

Hazard Evaluation of Indoor Air Quality in Bank Offices

IAQ is a crucial factor affecting the health, comfort, and productivity of workers, particularly those working in enclosed spaces like bank offices. This study aimed to evaluate the IAQ of a bank office’s operational area and vault by analyzing concentrations of CO2, TVOC, PM10, and PM2.5, as well as temperature, relative humidity, and air movement. Two different ventilation systems were compared to assess their impact on IAQ. The acquired data were statistically analyzed using mean comparison t-tests and hazard ratio analysis. The results revealed that indoor concentrations of PM2.5 and CO2 significantly contribute to the total hazard ratio, indicating the need to reduce their levels below reference values. The study also found that the ventilation system significantly affects indoor air quality, and concentrations of TVOC, CO2, PM10, and PM2.5 in the air are considerable. Significantly, the study found that bank offices with split unit air-conditioners had the highest mean CO2 levels, indicating poor ventilation. Overall, the study reveals that the building, activities, and ventilation in bank offices have a profound influence on IAQ parameters, primarily PM2.5 and CO2. Further research is required to formulate strategies for enhancing IAQ in these settings.

The Earth-Air Heat Exchanger System Performance Combined with a Solar Collector for Cooling an Indoor Space Room in Medan City

Cooling systems such as ventilation and air conditioning in rooms, offices, and homes have become one of today's most significant energy consumption aspects. Therefore, to reduce energy consumption, it is necessary to save energy. One way to save energy is by creating an alternative cooling system that does not consume electrical energy. One of them is the cooling system using the earth-air heat exchanger (EAHE). The research objective was to determine the EAHE system's performance combined with a solar collector for cooling an indoor space room in Medan city. This research is interesting because it utilizes cold temperatures from underground for a cooling system. The innovation obtained is a simple technology for the cooling process without depending on electrical and mechanical energy. The testing room has dimensions of 200 cm x 200 cm x 200 cm. Testing using a flat plate type solar collector to help air movement by taking advantage of air temperature differences. The testing process starts at 08.00 WIB to 17.00 WIB for several days. The measurement taken includes weather conditions include solar radiation intensity, ambient temperature, and air humidity. During the test, the solar radiation intensity ranged from 62.71-893.43 W/m2, the variation in ambient temperature from 24.65-35.26oC, and the average air humidity 69.80%. The experimental data showed that indoor air temperature fluctuation ranged from 23.01oC to 31.84oC, and the average room temperature was 27.71oC. This study resulted in an average effectiveness value of the EAHE system of 51.56%.

Users' Perception of Comfort Experienced in Academic Buildings of Selected Universities in Ogun State, Nigeria

In architectural design, the level of comfort experienced in the spaces created serve as one of the units of measurement in assessing a complete design. In a country tropical climate such as Nigeria, indoor environmental conditions are primarily influenced by many factors, including lighting, ventilation, indoor air quality, sound quality and building materials employed. This study investigated users’ comfort satisfaction level in relation to environmental design consideration factors in academic buildings of selected universities in Ota, Ogun State, Nigeria, with a view to identify areas for improvement towards making contributions that will help to improve users’ satisfaction in the development of academic environments. The study adopted a quantitative research method that used a structured questionnaire to collect data from 291 respondents, out of which 271 are students and 19 are lecturers. The users’ sample size was drawn from the Department of Architecture students and lecturers of two selected universities in the study area. The data were analyzed with the aid of Statistical Product and Service Solutions software and presented descriptively with the aid of tables. The results showed that majority of the respondents in the selected universities attested to the adequacy of the four environmental design consideration factors investigated, with the factors recording various levels of adequacies. In few areas were the factors were inadequate, the foremost reason was the inadequacy of the indoor air quality, followed by that of lighting before ventilation. Also, daylighting in classrooms and ventilation in offices was found to be inadequate in one of the universities, while the inadequacy of ventilation in offices in the other university was significantly high. The study recommended that building industry designers should pay more attended to means of achieving adequate indoor air quality, lighting and ventilation in academic buildings, without compromising achieving adequacy of sound quality found to be generally satisfactory. The study has implications for policy formulation, designs and researches that strive towards meeting users’ comfort satisfaction level in the development of academic environments.

Concentrations and human exposure to hexabromocyclododecane and tetrabromobisphenol A from the indoor environment in Bangkok metropolitan area, Thailand

Aim: This study investigated hexabromocyclododecane (HBCDD) and tetrabromobisphenol A (TBBPA) concentrations in indoor dust from houses, offices, and cars and estimated toddler and adult exposure to HBCDD and TBBPA through dust ingestion. Methods: The concentrations of HBCDD and TBBPA were measured in 47 indoor dust samples collected from the Bangkok metropolitan area, Thailand. All samples were analyzed for HBCDD and TBBPA using LC-MS/MS. The estimated daily intake (EDI) through dust ingestion was calculated from the median and 95th percentile concentrations of HBCDD and TBBPA. Results: HBCDD was detected in 47% of samples, and TBBPA was detected in all samples. The median concentrations of HBCDD were 6.7 ng g-1, &lt;0.7 ng g-1, and &lt;0.7 ng g-1 in cars, houses, and offices, respectively. The isomer composition of ∑HBCDD in dust was: α-HBCDD (40%-54%), γ-HBCDD (19%-40%), and β-HBCDD (17%-28%). In contrast, TBBPA was observed at higher concentrations, with median values of 674, 67, and 22 ng g-1 in offices, houses, and cars, respectively. Under a median exposure scenario, toddlers were exposed to 0.05 ng kg-1 bw day-1 for HBCDD and 0.25 ng kg-1 bw day-1 for TBBPA, with adults exposed to 0.01 and 0.06 ng kg-1 bw day-1 for HBCDD and TBBPA respectively. Conclusion: Concentrations of HBCDD in dust from Thai cars, homes, and offices are lower than those of TBBPA following the listing of HBCDD in the Stockholm Convention on Persistent Organic Pollutants and limited use of HBCDD in Thailand in applications such as building insulation foam. Concentrations of TBBPA in office dust significantly exceeded (P &lt; 0.05) those in house and car dust owing to the greater number of electronic appliances and poor natural ventilation in offices. EDIs for Thai toddlers exceeded those of adults under both median and high-end exposure scenarios. However, EDIs of HBCDD and TBBPA for the general Thai population were below the corresponding oral reference dose guidelines.

Experimental study of local effectiveness in the case of balanced mechanical ventilation in small offices

In this paper different mechanical ventilation methods were analysed in a test room, having similar dimensions with a small office room. A series of measurements were performed with mixing, displacement and personalized isothermal ventilation having one or two occupants in the room. The main goal of this research was to investigate the air cleaning performance of different ventilation strategies in the breathing zone. The CO2 emission of involved persons was determined and it was shown that one person released 13.4 l/h CO2 while two persons released 23.63 l/h CO2. Taking into account the spread of viruses and the requirements related to separation of persons in public buildings, measurements were carried out with “open” working desk and with “screened” desk as well. Using the balance equation of pollutants, the equation which describes the CO2 concentration variation in the closed space was developed and used for calculations. Air flow visualization was done for different ventilation modes. The local ventilation effectiveness was determined for each ventilation mode based on the measured and calculated CO2 concentrations depending on the provided fresh air flow, air distribution and occupants number. In the case of screened desk the personalized ventilation shows the highest local effectiveness (1.6–2.7 in comparison with 0.6–1.4 in the case of mixing and displacement ventilation).

Multi-parameter performance optimization for whole year operation of stratum ventilation in offices

Stratum ventilation with proper operation can provide thermal comfort and good inhaled air quality with energy efficiency. Previous studies mainly focused on stratum ventilation for cooling or heating in separate seasons, while little attention on stratum ventilation for whole year operation. Proper year-round operation of stratum ventilation is more complicated, with multiple ventilation operation parameters (i.e., the supply vane angle, supply air velocity, supply air temperature, and air outlet position) non-linearly affecting multiple mutually conflicting criteria of the ventilation performance (i.e., thermal comfort, air quality and energy efficiency). This study optimized the whole year operation of stratum ventilation by using a multi-parameter fitting technology. An experiment on stratum ventilation for both heating and cooling a typical office is conducted. Based on experimentally validated Computational Fluid Dynamics (CFD) simulations, the stratum ventilation performance is investigated. Ventilation effectiveness (Et) and air distribution performance index (ADPI) are introduced to be as the evaluation indicators to assess the performance of stratum ventilation. Results demonstrate that the mentioned factors play different roles in the thermal performance of stratum ventilation, and exist interactions among each other. The economic-comfort ratio is proposed to assess the indoor comfort and energy consumption simultaneously. Combining with building energy simulation technology and Marquardt method, the optimal year-round parameters of stratum ventilation under four air outlet positions in different climate zones can be determined. This study provides a comprehensive guide for stratum ventilation in practical application.

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.

Heating, Ventilation, and Air Conditioning (HVAC) Noise Detection in Open-Plan Offices Using Recursive Partitioning

Open-plan offices have lower construction costs, allowing for significant savings in space and, according to designers, facilitate communication between workers, thus, improving collaboration, as well as the exchange of ideas. For these reasons, this type of office has become widespread, while highlighting numerous limitations and various problems. These include the control of anthropic and electromechanical noise. In this study, measurements of the noise emitted by a heating, ventilation, and air conditioning (HVAC) system were carried out in an open-plan office. The average spectral levels in a 1/3 octave band were compared through correlation analysis, to identify any redundant data. A model was then adapted to evaluate the importance of the variables, in order to classify the characteristics, by importance. To reduce the number of predictor variables, a selection analysis of the characteristics was carried out. A subset of predictors was extracted to be used to produce an accurate prediction model. Finally, a model based on recursive partitioning, to detect the operating conditions of an HVAC system, was developed and applied, so as to provide insights into the development and application of this technique, in these contexts. The high accuracy of the model (Accuracy = 0.9981) suggests the adoption of this tool for several applications.

IoT-Enabled Humans in the Loop for Energy Management Systems: Promoting Building Occupants' Participation in Optimizing Energy Consumption

The governments of various countries continue to be alarmed by the adverse environmental impact of fossil energy, which could result in additional pollution, polar glaciers further melting, and intensified natural disasters. Around the world, the consumption of fossil energy is a socioeconomic and sociopolitical calamity. However, remedies in such circumstances depend, to a great extent, on the availability of cleaner energy resources and governmental policies on energy pricing, consumption, and conservation. According to a recent World Bank report, air pollution and its effects on the global economy cost roughly US$225 billion in 2013. The American Lung Association has also announced that more than 50% of the U.S. population lives within regions with serious air pollution concerns. Additionally, global warming stemming from increased levels of fossil energy consumption has resulted in fewer rainy days, more droughts, and the higher usage of air conditioning appliances, causing even greater fossil energy usage. Despite having clear perspectives of the perceived challenges, certain countries with a substantial number of energy consumers could soon be facing the adverse consequences of global warming. Continuing the current level of energy consumption in developing countries as well as consumption patterns in populated regions of the world could also result in a deep shortfall of energy supply, leading to higher energy costs. The U.S. Energy Information Administration has reported that, in 2015, roughly 40% of U.S. energy consumption was in residential and commercial buildings. In many office spaces, building operators' intentions are to offer employees comfort; however, improper settings for room temperature, area lighting, air conditioning, ventilation, and other services in offices, laboratories, and meeting rooms result in the inefficient use of electricity. Consequently, corrective countermeasures and effective policies are essential to cope with energy production and consumption.

A Psittacosis Outbreak among English Office Workers with Little or No Contact with Birds, August 2015.

Introduction:On 14th August 2015 an office manager informed Public Health England of five employees known to have been diagnosed with pneumonia over the previous three weeks. We investigated to establish whether an outbreak occurred and to identify and control the source of infection.Methods:We undertook case finding for self-reported pneumonia cases at local businesses (July-August 2015). Clinical samples from a hospitalised case were tested for common respiratory pathogens, but returned negative results. Further testing confirmed Chlamydia psittaci infection in this case (serology and PCR). We subsequently undertook C. psittaci testing for all cases, redefining them as confirmed (C. psittaci PCR or high antibody titre via serology) or probable (inconclusive C. psittaci serology). Twenty-eight day exposure histories informed descriptive epidemiological analysis. We conducted an environmental investigation at the office to identify potential sources of exposure.Results:We identified six office workers with pneumonia; four met case definitions (three confirmed, one probable) with symptom onset between 29th July and 4th August 2015. Workplace was the only epidemiological link and only one case reported limited, indirect bird contact. Environmental investigations identified pigeons roosting near the office which were being fed by workers (none cases).Discussion:This was a probable outbreak of psittacosis with no direct bird-to-human contact reported. Cases recovered after receiving appropriate antibiotics. Feeding of pigeons was stopped. A deep clean of office ventilation systems was conducted and workers were advised to avoid bird contact. We hypothesised that indirect environmental exposure to infected pigeons was to the source of this outbreak. This work provides evidence that health professionals should consider psittacosis in the differential diagnosis of cases of severe or atypical respiratory illness even without overt bird contact.

Comparing the indoor environmental quality of a displacement ventilation and passive chilled beam application to conventional air-conditioning in the Tropics

The satisfaction of occupants with an indoor environment supplied by a conventional central VAV air-conditioning system was compared to a novel system represented by decentralized ventilation units and a network of passive chilled beams. In parallel with occupant survey measurement of indoor air quality (IAQ) parameters was conducted with the developed wireless IAQ sensing kits. The same occupant cohort was surveyed for both systems, as occupants of the conventionally-conditioning office, known as the ‘Previous Office’ later moved into the office conditioned by the novel system, known as the ‘3for2 Office’. We observed that the perceived thermal comfort and air quality satisfaction of the occupants were markedly higher in the 3for2 Office than in the Previous Office. While occupants of the 3for2 Office could raise or lower indoor air temperatures, they appeared to be consistently satisfied with higher indoor air temperatures than that set by the building management of the Previous Office. The primarily Singaporean occupants of the 3for2 Office also felt thermally comfortable even when indoor air velocities in the office were measured to be below 0.1 m/s recommended by Singaporean Standards. The 3for2 Office's ventilation system was designed to supply outdoor air beyond minimal required ventilation rates, which lead to relatively low levels of CO2 and PM2.5 concentrations in the 3for2 office. We believe that higher ventilation rates resulting in lower pollutant concentrations are responsible for a higher-than-average survey score on air quality satisfaction. We also believe that enabling occupants to set air temperature in the space resulted in higher-than-average thermal comfort satisfaction.

Building Ventilation as an Effective Disease Intervention Strategy in a Dense Indoor Contact Network in an Ideal City.

Emerging diseases may spread rapidly through dense and large urban contact networks, especially they are transmitted by the airborne route, before new vaccines can be made available. Airborne diseases may spread rapidly as people visit different indoor environments and are in frequent contact with others. We constructed a simple indoor contact model for an ideal city with 7 million people and 3 million indoor spaces, and estimated the probability and duration of contact between any two individuals during one day. To do this, we used data from actual censuses, social behavior surveys, building surveys, and ventilation measurements in Hong Kong to define eight population groups and seven indoor location groups. Our indoor contact model was integrated with an existing epidemiological Susceptible, Exposed, Infectious, and Recovered (SEIR) model to estimate disease spread and with the Wells-Riley equation to calculate local infection risks, resulting in an integrated indoor transmission network model. This model was used to estimate the probability of an infected individual infecting others in the city and to study the disease transmission dynamics. We predicted the infection probability of each sub-population under different ventilation systems in each location type in the case of a hypothetical airborne disease outbreak, which is assumed to have the same natural history and infectiousness as smallpox. We compared the effectiveness of controlling ventilation in each location type with other intervention strategies. We conclude that increasing building ventilation rates using methods such as natural ventilation in classrooms, offices, and homes is a relatively effective strategy for airborne diseases in a large city.

Establishing an image-based ground truth for validation of sensor data-based room occupancy detection

Occupancy controlled heating, ventilation and air condition in offices are a mean to avoid energy waste due to over-conditioning of rooms. Occupancy detection methods based on sensor data that is already available in a building for other reasons than occupancy detection are therefore of great interest. However, such methods need to be validated according to a ground truth. This paper presents an image-based method for automatic establishment of a reliable and anonymous ground truth at entrance areas where the room height only allow the camera to be installed at 2.3–3.0m above the floor. The method deploys various image processing techniques to infrared depthframe images recorded with a ceiling-mounted Kinect camera to anonymously detect and track persons entering or leaving a room and, consequently, counting the number of occupants in the room. The method demonstrated an accuracy of more than 98% in a stress test, 100% in a range of relevant function test and 99% in a three week long room occupancy test.

Impact of natural versus mechanical ventilation on simulated indoor air quality and energy consumption in offices in fourteen U.S. cities

This study simulated the impacts of natural versus mechanical ventilation in offices on indoor concentrations of key pollutants, as well as energy usage. A typical office building was modeled in EnergyPlus in fourteen U.S. cities to assess the energy use and airflows delivered by an ideal variable air volume (VAV) system in a range of climates. Two mechanical ventilation strategies (minimum; minimum + economizer control) were modeled, as well as two analogous natural ventilation strategies, which used a fan-driven recirculation hybrid system to maintain setpoints if necessary. Outputted hourly ventilation, recirculation, and infiltration rates were used in an indoor air model with city-specific outdoor monitoring data to compute indoor concentrations of carbon monoxide, carbon dioxide, formaldehyde, nitrogen dioxide, ozone, and fine particles (PM2.5). Natural ventilation decreased energy use, due to a wider temperature setpoint band for natural ventilation scenarios and somewhat lower fan energy use. Indoor concentrations and indoor/outdoor (I/O) ratios of all pollutants were similar for analogous strategies, except PM2.5, which was reduced by filtration in the supply air. Median PM2.5 I/O ratios were a factor of 1.2, 2.2, and 6.3 larger for natural versus mechanical ventilation strategies with MERV 8, 11, and 16 filters, respectively. The filtration impact was so strong that PM2.5 I/O ratios differed little between mechanical minimum and economizing strategies, especially as filter efficiency increased. These results can be used to understand tradeoffs of energy and indoor air pollution trends of natural versus mechanical ventilation.

Particulate matters from diesel heavy duty trucks exhaust versus cigarettes emissions: a new educational antismoking instrument

Background: Indoor smoking in public places and workplaces is forbidden in Italy since 2003, but some health concerns are arising from outdoor secondhand smoke (SHS) exposure for non-smokers. One of the biggest Italian Steel Manufacturer, with several factories in Italy and abroad, the Marcegaglia Group, recently introduced the outdoor smoking ban within the perimeter of all their factories. In order to encourage their smoker employees to quit, the Marcegaglia management decided to set up an educational framework by measuring the PM1, PM2.5 and PM10 emissions from heavy duty trucks and to compare them with the emissions of cigarettes in an indoor controlled environment under the same conditions.&#x0D; Methods: The exhaust pipe of two trucks powered by a diesel engine of about 13.000/14.000 cc3 were connected with a flexible hose to a hole in the window of a container of 36 m3 volume used as field office. The trucks operated idling for 8 min and then, after adequate office ventilation, a smoker smoked a cigarette. Particulate matter emission was thereafter analyzed.&#x0D; Results: Cigarette pollution was much higher than the heavy duty truck one. Mean of the two tests was: PM1 truck 125.0(47.0), cigarettes 231.7(90.9) p = 0.002; PM2.5 truck 250.8(98.7), cigarettes 591.8(306.1) p = 0.006; PM10 truck 255.8(52.4), cigarettes 624.0(321.6) p = 0.002.&#x0D; Conclusions: Our findings may be important for policies that aim reducing outdoor SHS exposure. They may also help smokers to quit tobacco dependence by giving them an educational perspective that rebuts the common alibi that traffic pollution is more dangerous than cigarettes pollution.

Particulate matters from diesel heavy duty trucks exhaust versus cigarettes emissions: a new educational antismoking instrument.

BackgroundIndoor smoking in public places and workplaces is forbidden in Italy since 2003, but some health concerns are arising from outdoor secondhand smoke (SHS) exposure for non-smokers. One of the biggest Italian Steel Manufacturer, with several factories in Italy and abroad, the Marcegaglia Group, recently introduced the outdoor smoking ban within the perimeter of all their factories. In order to encourage their smoker employees to quit, the Marcegaglia management decided to set up an educational framework by measuring the PM1, PM2.5 and PM10 emissions from heavy duty trucks and to compare them with the emissions of cigarettes in an indoor controlled environment under the same conditions.MethodsThe exhaust pipe of two trucks powered by a diesel engine of about 13.000/14.000 cc3 were connected with a flexible hose to a hole in the window of a container of 36 m3 volume used as field office. The trucks operated idling for 8 min and then, after adequate office ventilation, a smoker smoked a cigarette. Particulate matter emission was thereafter analyzed.ResultsCigarette pollution was much higher than the heavy duty truck one. Mean of the two tests was: PM1 truck 125.0(47.0), cigarettes 231.7(90.9) p = 0.002; PM2.5 truck 250.8(98.7), cigarettes 591.8(306.1) p = 0.006; PM10 truck 255.8(52.4), cigarettes 624.0(321.6) p = 0.002.ConclusionsOur findings may be important for policies that aim reducing outdoor SHS exposure. They may also help smokers to quit tobacco dependence by giving them an educational perspective that rebuts the common alibi that traffic pollution is more dangerous than cigarettes pollution.

Natural Ventilation and Forced Warm Air Ventilation in Offices

The paper is oriented on the natural ventilation and forced warm air ventilation systems in offices. The basic element of natural ventilation system in office building is double skin facade. The natural air circulation is undertaken by the right shaping of vertical shafts for exhaust air. Furthermore, the intelligent double skin facade in transitional period contributes to the heating and in summer to natural cooling of offices. Therefore, the forced warm air ventilation, which is provides heating of offices, can operate in saving mode and can be supplemented by radiant floor heating. By the effort to approach to zero energy balance, it is important to undertake thermal comfort. Therefore, I did experimental laboratory measurements for forced warm air ventilation and I also did it because of comparison for radiant floor heating. In this paper, I will present scientific analysis and the outputs from my own measurements. In the conclusion of this paper on the basis of outputs of experimental measurements I will define the principles for designing forced warm air ventilation and radiant floor heating in offices.