Indoor Air Quality In Offices Research Articles

Comparative analysis of indoor air quality in offices with different ventilation mechanisms and simulation of ventilation process utilizing system dynamics tool

Comparative analysis of indoor air quality in offices with different ventilation mechanisms and simulation of ventilation process utilizing system dynamics tool

Indoor air Quality in Offices and Classrooms in Public Utility Building - A Case Study

A microbiological analysis of indoor air quality in offices, lecture rooms, and hallways in a public utility building has been carried out in the Lubuskie Voivodship (Poland). In one of the storage rooms, the presence of fungi on the building partition was found in the place of water infiltration as a result of a technological failure in the building. A total of 17 non-residential interiors were examined. The total number of psychrophilic and mesophilic bacteria and the total number of fungi were sampled by the collision method with the air sampler. A qualitative analysis has been performed of fungi present in the indoor air and from building partition of the studied interiors. A total of 11 species of fungi have been specified. Relative humidity and air temperature were measured with a hygrometer. The studies showed that the number of psychrophilic bacteria in indoor air was in the range 0–730 CFU/m<sup>3</sup>, while the number of mesophilic bacteria was slightly higher (0 - 896 CFU/m<sup>3</sup>). A high level of contamination and a large number of fungi (734 CFU/m<sup>3</sup>) were found in the indoor air of storage room, where the problem of biodeterioration of building partitions occurred. In the remaining rooms, the level of microorganisms was low or moderate. Microbiological tests of the outdoor air (background) did not reveal an excessive number of microorganisms in the air.

Risk Assessment of Indoor Air Quality and Its Association with Subjective Symptoms among Office Workers in Korea.

The 2014 Time-Use Survey of Statistics Korea revealed that office workers are increasingly spending more than eight hours at work. This study conducted an exposure assessment for office workers in Korea. Indoor and outdoor air pollutants were measured in offices. A self-administered questionnaire was employed to determine work information, indoor air quality (IAQ) awareness, and subjective symptoms for 328 workers. Indoor air concentrations for measured air pollutants were below IAQ guideline values. The average concentrations of target air pollutants did not show significant differences except for benzene, which had relatively a higher concentration in national industrial complexes. The indoor benzene, ethylbenzene, and acetaldehyde concentrations were higher in offices where workers were having dry eye, ophthalmitis, and headache symptoms. This study provides reference values to manage IAQ in offices, suggesting that if the benzene concentration exceeds 4.23 μg/m3 in offices, it could cause dry eye symptoms. Considering the increasing working hours for office workers and health effects, workers’ exposure to indoor pollutants should be reduced. In addition, the IAQ was heavily influenced by outdoor air levels and various indoor sources. Therefore, in areas with relatively high air pollution, greater monitoring and management is required considering the influence of outdoor air quality.

Investigation of indoor air quality in six office buildings in Chengdu, China based on field measurements

Indoor air pollution is of a growing concern in China. The nation’s growing urban work force spends a majority of daily time in the office, thus office indoor air quality (IAQ) can be a key determinant of worker’s wellbeing. Yet, information on office IAQ in rapidly developing southwestern China remains scarce. To address this knowledge gap, we conducted an observational study based on continuous monitoring in six office buildings in Chengdu, Sichuan Province, to investigate the concentration and variability of indoor particulate matter (PM2.5) and carbon dioxide (CO2). Hourly indoor concentrations for PM2.5 and CO2 were 0–459 µg/m3 and 375–1102 ppm, respectively, with considerable intra-building and inter-building variability. Indoor PM2.5 exhibited temporal association with ambient PM2.5, while indoor CO2 exhibits both diurnal and weekly patterns. Four out of the six buildings showed a reduction in indoor PM2.5 during work hours, suggesting functional filtration systems. However, we observed daily accumulation of indoor CO2, suggesting ineffective ventilation. Indoor PM2.5 pollution could be of health concern as all buildings experienced days when indoor PM2.5 concentration was above WHO recommendation for at least 50% of the day. Multivariate linear model predicts that every 1 µg/m3 increase in ambient PM2.5 is associated with a 0.60 µg/m3 increase in indoor PM2.5. Building-specific multivariate models show work time, weekday, outdoor PM2.5 are significantly associated with indoor PM2.5 concentration. We hope findings from this study can inform future indoor pollution mitigation strategies.

Investigation of indoor air quality in offices and residential homes in an urban area of Poland

The quality of air in various types of rooms is an extremely important issue, because contaminants occurring there, even at low concentrations, can cause health problems, especially for those living or working in these locations. The aim of this study was to compare indoor air quality (IAQ) in offices, flats and a residential building in Upper Silesia. Volatile organic compounds (VOCs) were self-concentrated, thermally desorbed (TD) and then analysed using gas chromatography (GC). The mean concentrations of the 16 determined VOCs ranged from 18 to 56 μg/m3. The average concentration of carcinogenic benzene was about 1 μg/m3 in offices and flats, while in the residential building it was up to 3.6 μg/m3. In residential building, increased concentrations of m, p-xylene, and ethylbenzene and styrene have also been observed. Toluene predominated in all studied rooms. High and very high indoor-to-outdoor (I/O) ratios were found. Indoor VOC sources produce more contaminants than are obtained from the infiltration of outdoor air.

Investigation of Indoor Air Quality in six office buildings in Chengdu, China based on continuous monitoring data

Indoor air pollution is of a growing concern in China. The nation’s growing urban work force spends prolonged periods in office, thus office indoor air quality (IAQ) can be a key determinant of worker’s wellbeing, yet, IAQ literature on China’s office space remains scarce. To address such knowledge gap, this study conducted continuous monitoring in six office towers in Chengdu, China to investigate two major indoor pollutants: PM2.5 and CO2. The participating office buildings were Grade-A certified and fully occupied. Indoor concentration for PM2.5 and CO2 ranged between 1-459 μg/m3 and 375-1102 ppm respectively, with considerable intra-building and inter-building variability. Time-series analysis suggests diurnal and weekly pattern for indoor CO2, and temporal association between indoor and ambient PM2.5. Filtration and ventilation efficiencies varied across buildings, and these buildings experienced various degrees of penetration by outdoor PM2.5 and indoor accumulation of CO2 on a daily basis. On days with ambient pollution, indoor pollution persisted. Multivariate model predicts an average of 0.6 μg/m3 increase in indoor PM2.5 for every 1 μg/m3 increase in ambient PM2.5. To our knowledge, this is the first systematic study of office buildings in China with findings potentially inform future IAQ management strategies.

Occurrence of moisture damages and perceived indoor air quality in offices

Occurrence of moisture damages and perceived indoor air quality in offices Background Indoor air and mold investigations are often performed in buildings with reported complaints of indoor air qual...

Occupant acceptance as a screening parameter for indoor environmental assessments

PurposeThis study seeks to investigate the usefulness of occupant acceptance as a preliminary screen measure for offices' indoor air quality (IAQ). An effective alert indication of IAQ problems of a concerned indoor environment would help to promote good IAQ.Design/methodology/approachThe study evaluates the hypothesis that the occupant dissatisfaction with the overall indoor environment provides an indication of IAQ problems. Hence, occupant dissatisfaction would be used as a screening parameter to identify problematic IAQ regarding some IAQ criteria in subsequent IAQ assessments. The hypothesis was tested with a database of regional cross‐sectional measurement in 490 offices within Hong Kong.FindingsThe occupants' dissatisfaction with the indoor environmental quality (IEQ) was correlated with the IAQ assessment results of nine IAQ assessment parameters regarding some IAQ criteria for air‐conditioned offices. At certain screening levels of predicted IEQ dissatisfaction, the performance of the proposed screening tool, indicating unsatisfactory office IAQ, was evaluated in terms of the test sensitivity, specificity, predictive values and Yule's Q statistics. The results showed that occupants' response to the indoor environment produced indications of unsatisfactory IAQ regarding the requirement of an “Excellent” office.Research limitations/implicationsThe subjective feelings of occupants are capable of identifying marked indoor environmental problems, but cannot identify the “marginal” IAQ problem cases.Practical implicationsThe study shows the usefulness of using occupant acceptance to identify the unrecognized IAQ problems for air‐conditioned office environment. Using the identification model developed in the study, all the suspected cases were associated with a high chance of IAQ dissatisfaction and subsequent IAQ assessments were thus recommended.Originality/valueThe paper proposes a new identification method to identify the unrecognized IAQ problems which may indicate unsatisfactory IAQ. Also, the occupants' responses on the indoor environment are quantified.

Indoor Air Quality Benchmarking for Air Conditioned Offices

AbstractMaintaining acceptable indoor air quality (IAQ) for a healthy workplace is of major concern. Based on proper assessment methodologies and monitoring plans, policymakers have proposed indicators to address office IAQ. To streamline the assessment of office IAQ performance and offer incentives for maintaining better IAQ, this study proposes and investigates the feasibility of simple IAQ benchmarking using an IAQ indicator. The IAQ indicator is a benchmarking parameter derived from exposure concentrations of three selected common indoor air pollutants. This benchmark used a 5‐star rating system which assigned 1 star to the top 10% of samples with the highest levels of the three pollutants, 2 stars to the next 22.5%, 3 stars to the next 35%, 4 stars to the next 22.5% and 5 stars to the bottom 10%. The application of this benchmarking system was tested in 525 air conditioned offices in Hong Kong. Taking an existing IAQ certification scheme as a reference, the proposed benchmarking system proved to be useful in distinguishing offices with different IAQ labels, and illustrate the performance of office IAQ with different star ratings. Therefore, the proposed simple method can help promote better IAQ and serve as a screening assessment for IAQ in air conditioned offices of Hong Kong.

Using Carbon Dioxide Concentration to Assess Indoor Air Quality in Offices

Carbon dioxide (CO2) concentration is commonly used as a surrogate indicator for assessing indoor air quality (IAQ) and ventilation efficiency. The measurement and analysis of average indoor CO2 concentration is useful to understand the performance of a ventilation system. However, uncertainties due to the ventilation rate effectiveness as well as the initial state, build-up, fluctuation, and decay of indoor CO2 concentration from occupant load variation have not been addressed in many measurements; considerable measurement efforts are obligatory. This study, taking the long-term CO2 measurement and occupant profile of a typical open-plan office building as reference, has developed a database to examine the probable errors of an alternative sampling scheme for assessing indoor CO2 level in which the average pollutant concentration is obtained from two short sampling periods in two sampling sessions when the building is occupied. The results show that the assessed CO2 level deviates from the long-term average and the probable errors correlate with the required measurement time and occupant load profile. At certain confidence levels, the potential reductions in measurement time of the alternative scheme, as compared with an 8-h continuous one, will be up to 30%, some 20% less than the reduction of measurement time for assessing indoor radon level.

Epistemic evaluation of policy influence on workplace indoor air quality of Hong Kong in 1996—2005

Long-term measurement results of indoor air quality (IAQ) over a general community can be used to evaluate the effectiveness of mitigation measures for IAQ improvement of premises. However, this approach requires considerable measurement efforts and thus the complete data sets are not available in many circumstances. This study proposes an epistemic approach in estimating the probable influences of an IAQ policy for Hong Kong offices, using the regional IAQ measurement databases of offices in 1996, 1998—2001 and 2004—2005. After the implementation of the IAQ policy in 1997—1999, measurement results of IAQ in offices were collected and were used to quantify the IAQ improvement for Hong Kong offices. It is noted that IAQ dissatisfaction due to air pollutants predominated by indoor emissions of volatile organic compounds (VOCs) might need additional attentions for an effective IAQ improvement programme. Practical application: This study provides updated information on the forecasts of IAQ in air-conditioned offices of Hong Kong due to the influence of the IAQ policy implemented in 1997—1999. It is a useful source of reference for policymakers and decision makers in evaluating an indoor air pollution control policy for air-conditioned offices.

Influence of indoor air quality (IAQ) objectives on air-conditioned offices in Hong Kong

It is costly to sample all air pollutants of a general community. Air sampling should be conducted based on a practical assessment strategy and monitoring plan. In Hong Kong, the Environmental Protection Department (HKEPD) launched an Indoor Air Quality (IAQ) certification scheme to grade workplace IAQ as 'Excellent' or 'Good' by measuring the levels of nine common indoor air pollutants, namely carbon dioxide (CO(2)), carbon monoxide (CO), respirable suspended particulates (RSP), nitrogen dioxide (NO(2)), ozone (O(3)), formaldehyde (HCHO), total volatile organic compounds (TVOC), radon (Rn), and airborne bacteria count (ABC). Although average office IAQ performance has been improved since the implementation of this certification scheme, there are still resource issues and technical difficulties. To streamline the assessment of office IAQ performance, this study proposes a simple index of IAQ benchmarks formulated in compliance with the HKEPD requirements. In particular, three of the nine listed common air pollutants were selected as the 'representatives' for the overall satisfactory IAQ. Together with the assessment results of 422 Hong Kong air-conditioned offices, the index was evaluated in terms of test sensitivity, specificity and predictive values. Proved to be feasible to describe the IAQ of some air-conditioned offices, this IAQ index would be a useful tool for policymakers, building owners and professionals to quantify IAQ performance in offices and to make decisions on resources and manpower management for efficient mitigation actions.

An Epistemic Indoor Air Quality Assessment Protocol for Air-Conditioned Offices

Long-term measurement could be the best approach to determine the average pollutant concentration of an indoor environment for decisions on mitigation measures. This approach requires considerable measurement effort for accurate results and hence indoor air quality (IAQ) assessment methods that need less effort have been developed. This study proposes an epistemic approach for assessing an acceptable office IAQ against certain indoor air pollutant exposure limits. Together with the prior understanding of failure rates of IAQ determined from a number of extensive survey studies, a sample test result of pollutant levels and the uncertainties of different sampling schemes, the probability of satisfactory IAQ for an assessed air-conditioned office could be quantified. In particular, assessment of an acceptable IAQ for some air-conditioned offices in Hong Kong was demonstrated by taking CO2 as an example pollutant. Accuracy of the failure rates was improved by the application of sampling correction factors and Bayesian statistics. The probabilities of an acceptable office IAQ were evaluated against a CO2 level limit. This approach would be useful for IAQ assessment in some air-conditioned offices.

Characteristics of emissions of air pollutants from burning of incense in temples, Hong Kong

Field investigations of target air pollutants at two of the most famous temples in Hong Kong were conducted. The air pollution problems in these two temples during peak and non-peak periods were characterized. The target air pollutants included particulate matters (PM(10), PM(2.5)), volatile organic compounds (VOCs), carbonyl compounds, carbon monoxide (CO), nitrogen oxides (NO(x)), methane (CH(4)), non-methane hydrocarbons (NMHC), organic carbon (OC), elemental carbon (EC), and inorganic ions (Cl(-), NO(3)(-), SO(4)(2-), Na(+), NH(4)(+), and K(+)). The pollutant levels of the two temples during peak period were shown to be significantly higher than those during non-peak period. The highest average CO level was obtained at Temple 1 during peak period, which exceeded IAQO 8-h Good Class criteria. In general, the average PM(2.5)/PM(10) ratios were approximately 82%. The results revealed that the fine particulates (PM(2.5)) constituted the majority of suspended particulates at both temples. It was noted that formaldehyde was the most abundant carbonyl compounds, followed by acetaldehyde. At Temple 1 during peak period, the average benzene concentration exceeded almost 8 times more than Indoor Air Quality Objectives for Office Buildings and Public Places (IAQO) [HKEPD, 2003. Guidance notes for the management of indoor air quality in offices and public places. Indoor air quality management group, The Government of the Hong Kong Special Administrative Region.] Good Class criteria. The average OC/EC ratios ranged from 2.6 to 17 in PM(10) and from 4.2 to 18 in PM(2.5) at two temples, which suggested that OC measured in these two temple areas may be due to both direct emission from incense burning and secondary formation by chemical reactions. The total mass of inorganic ions, organic carbon, and elemental carbon accounted for about 71% in PM(2.5) and 72% in PM(10).

Urban air quality and carboxyhemoglobin levels in a group of traffic policemen

Toxicological potential of carbon monoxide (CO) on humans is well known. Nevertheless, CO is still considered as a useful marker to detect some environmental and occupational human risk factors typical of cities. The role played by traffic pollution, indoor air quality in offices and tobacco smoke on the expression of carboxyhemoglobin (COHb%) levels was investigated in a large group of traffic policemen in Torino city (North-Western Italy). At the end of the working shift, 228 policemen responded to a questionnaire, weight and height recorded, urine spot samples collected to measure cotinine as biomarker of tobacco smoke exposure, and an arterial blood sample was taken to measure COHb levels. Data of outdoor urban air-CO were collected and to each subject a "CO outdoor air measurement" was related to his/her COHb level. Considering the annual trend of air-CO pollution from 2002 to 2004, one can assume that a general improvement of air quality in Torino was evident. Taking into account the environments where policemen work (urban outdoor and indoor), and analyzing their COHb% content, the traffic-congested areas, and, in general, the outdoor urban environment were equally risky as offices. Furthermore, if compared to CO arising from traffic-congested areas or other outdoor environments, the traffic policemen in Torino city demonstrate COHb% levels largely due to smoking habits.

Experimental Validation of the Laboratory Air Handling Unit System (LAHU)—Part I: Winter Operation

The laboratory air handling unit (LAHU) system for laboratory buildings has been developed and optimized. Theoretical study has concluded that the LAHU with optimal outside air control and optimal heat recovery control significantly reduces thermal energy use, saves pump power consumption and improves office indoor air quality. This paper presents validation experiments of the LAHU energy performance for the winter operation in a large university research building including detailed experimental methodology, procedures and experimental energy savings results. The experiments establish that the LAHU can reduce annual heating energy consumption by over 30% and can reduce heat recovery pump power by over 50%peryear for this typical laboratory building. The experimental validation of the LAHU for the summer operation will be reported in a followup paper.

Characteristics of emissions of air pollutants from mosquito coils and candles burning in a large environmental chamber

The objective of this study was to characterize the emissions of air pollutants from mosquito coils and candles burning in a large environmental test chamber. The target pollutants included particulate matters (PM 10, PM 2.5), carbon monoxide (CO), nitrogen oxides (NO x ), methane (CH 4), non-methane hydrocarbons (NMHC), volatile organic compounds (VOCs) and carbonyl compounds. The average PM 10 concentrations for all tested mosquito coils exceeded Excellent and Good Classes objectives specified by Indoor Air Quality Objectives for Office Buildings and Public Places (IAQO) [ HKEPD, 2003. Guidance Notes for the Management of Indoor Air Quality in Offices and Public Places. Indoor Air Quality Management Group, The Government of the Hong Kong Special Administrative Region]. The emission factors (mg g −1 mosquito coil) of mosquito coils combustion were: PM 2.5, 20.3–47.8; PM 10, 15.9–50.8; CO, 74.6–89.1; NO, 0.1–0.5; NO 2, n.d.–0.1; NO x , 0.1–0.5; CH 4, n.d.–4.7; NMHC, 0.1–5.7. Formaldehyde and acetaldehyde were the most abundant carbonyls species in the coil smoke. The average concentrations of formaldehyde and benzene of all tested mosquito coils exceeded Good Class of IAQO. Nitrogen oxides were the most abundant gas pollutants relating to candle burning among all target air pollutants. The candle made of gel (CAN 4) would emit more air pollutants than the paraffin candles (CAN 1, 2 and 3) and beeswax candle (CAN 5). Among five candles tested, CAN 5, the one made of beeswax, generated relatively smaller amount of air pollutants. It was noted that the concentrations of most VOCs from candles combustion were below the detection limit.

Review of the Objective Pollutant Levels in the IAQ Certification Scheme

The Indoor Air Quality (IAO) Certification Scheme is one of the major components of the IAQ Management Programme proposed by the Hong Kong SAR Government. The Scheme incorporates the Guidance Notes (GN) on the Management of Indoor Air Quality in Offices and Public Places. The draft GN issued in November 1999 has been under scrutiny and Subject to trial implementation. The IAQ objectives stated in the GN define indoor concentration standards for 9 major air contaminants on a health-related basis, as well as requirements for 3 physical indoor environmental parameters. This paper critically reviews the rationales for the IAQ criteria based on the standards adopted in other countries and recommended by several international organisations. It is concluded that a number Of Level-2 criteria should be revised to a certain extent in order to maintain an appropriate level of protection for the general public. It is argued that there exists a misconception of a-hour averages for both respirable suspended particulate...

Experimental study of indoor air quality, energy saving and analysis of ventilation norms in climatised areas

Currents trends in indoor air quality involve prevention as well as the need for specific legislation (norms) to protect people’s health and to achieve greater levels of comfort. It is currently one of the most important areas of study [5,6,10]. The existence of different indoor air quality norms and standards depending on the country involved has made it difficult to determine when these standards really ensure low levels of indoor pollutants. The requirements of the future European ventilation norm (prENV 1752) make a detailed study on the energy implications of the problem essential. This work represents an original study in this field, where the results obtained from a series of practical indoor air quality and ventilation measurements are explored. These results have been obtained using photoacoustic spectroscopy (PAS) and the trace gas (sulphur hexafluoride) technique in a series of Spanish office buildings with varying climatisation systems. The results obtained in ventilation flows as well as an analysis for comparison purposes with data on Spanish, American (ASHRAE 62R) and European norms (prENV 1752) are presented. The conclusions which may be drawn are also offered. Finally, the work shows a ventilation flow which achieves high environmental indoor air quality in offices while at the same time offering compatibility with high energy saving.

Where are we in understanding the effects of where we are?

This paper briefly reviews research studies of interest to environmental ergonomists. It includes some recent work on the health effects of office lighting, especially the effects of daylighting, fluorescent lighting and full-spectrum lighting. It also covers studies of indoor air quality in offices, especially investigations of localized air filtration and the sick building syndrome. It argues the value of a systematic, ergonomics approach to designing the built environment.