Indoor Climate and Indoor Air Quality in Residential Buildings

In buildings which were built within the last 15 to 20 years, or which have been retrofitted, and which do notfeature a mechanical ventilation system, air changes between 0.01 h^?1 and 0.5 h^?1 were measured while windows were closed. In the bedrooms of such buildings, when doors and windows were closed, CO₂ concentrations of up to 4300 ppm were measured whereby the 1500 ppm limit was often exceeded. Simulation calculations and diverse measurements using different door positions with simultaneously closed windows have shown that with the door open more than 10 cm, and a minimal air exchange in the whole of an apartment of 0.1 h^?1, a CO₂ concentration of I500 ppm was not or was only insignifiantly exceeded even after 10 hours. Investigations in a dwelling fined with a mechanical ventilation system have shown that air quality and the indoor climate parameters were in an optimal range.     

窗户对自然通风房间室内空气品质的影响

通过计算机模拟,以找出夏热冬暖地区居住建筑为满足室内舒适性的最小开窗面积。     

Outdoor Air Contaminants and Indoor Air Quality under Transient Conditions

The indoor concentrations of contaminants originating from outdoor sources have been measured and calculated under transient conditions. The results show that contaminants that are supplied to an office building via the ventilation system can reach considerably high concentration levels. The indoor/outdoor concentration ratio and time lag are dependent on the air change rate. In buildings with low air change rates the indoor concentration variations are smoothed out compared to buildings with high air change rates. The results from the theoretical model are compared to the results from both laboratory and field measurements and the model is verified for well mixed conditions in a 20 m³ test chamber. The model can be used to simulate different control strategies for reduction of indoor contaminant concentrations related to outdoor sources. One such control strategy is based on reduction of the outdoor air change rate during periods with peak outdoor contaminant concentrations.     

Impact of Temperature and Humidity on the Perception of Indoor Air Quality

Abstract Sensory responses to clean air and air polluted by five building materials under different combinations of temperature and humidity in the ranges 18-28°C and 30-70%RH were studied in the laboratory. A specially designed test system was built and a set of experiments was designed to observe separately the impact of temperature and humidity on the perception of air quality/odour intensity, and on the emission of pollutants from the materials. This paper reports on the impact on perception. The odour intensity of air did not change significantly with temperature and humidity; however, a strong and significant impact of temperature and humidity on the perception of air quality was found. The air was perceived as less acceptable with increasing temperature and humidity. This impact decreased with an increasing level of air pollution. Significant linear correlations were found between acceptability and enthalpy of the air at all pollution levels tested, and a linear model was established to describe the dependence of perceived air quality on temperature and humidity at different pollution levels.     

Impact of Temperature and Humidity on Perception of Indoor Air Quality During Immediate and Longer Whole-Body Exposures

Abstract Acceptability of clean air and air polluted by building materials was studied in climate chambers with different levels of air temperature and humidity in the ranges 18–28°C and 30-70% relative humidity (RH). The acceptability of the air quality immediately after entering a chamber and during the following 20-min whole-body exposure was assessed by 36 untrained subjects who maintained thermal neutrality by modifying their clothing. The results confirm the significant decrement of the acceptability with increasing temperature and humidity, as shown in a previous study with facial exposures. The odour intensity was found to be independent of temperature and humidity. A linear relation between acceptability and enthalpy of air was again observed by this experiment. No significant difference was observed between the immediate acceptability and the acceptability during the following 20-min exposure, i.e., no adaptation took place. Both the immediate assessment of acceptability and the assessments during the 20-min exposure were independent of the air temperature and humidity to which the subjects were exposed before entering the chamber. The results further indicate that a notable decrement of the ventilation requirement may be achieved by maintaining a moderate enthalpy of air in spaces.     

European Indoor Air Quality Audit Project in 56 Office Buildings

Abstract A European project started at the end of 1992, in which, in addition to current methods, trained sensory panels were used to investigate office buildings all over Europe. The main aim of this EC-Audit was to develop assessment procedures and guidance on ventilation and source control, to help optimize energy use in buildings while assuring good indoor air quality. In each of nine countries, six or more office buildings were selected. Measurements were performed at five selected locations in each building. The buildings were studied while normally occupied and ventilated to identify the pollution sources in the spaces and to quantify the total pollution load caused by the occupants and their activities, as well as the ventilation systems. The investigation included physical and chemical measurements, assessment of the perceived air quality in the spaces by a trained sensory panel, and measurement of the outdoor air supply to the spaces. A questionnaire for evaluating retrospective and immediate symptoms and perceptions was given to the occupants of the buildings. The building characteristics were described by use of a check-list. The annual energy consumption of the buildings and the weather conditions were registered. This paper presents results and conclusions of the audit in 56 buildings in Europe. However, the analysis and discussions of the results are a summary of the work done, and are focused mainly on comparison between sensory assessments and the other measurements performed. Furthermore, this paper brings the results of the study based on a two-factor analysis. A paper dealing with results on a multifactorial analysis is in preparation.     

在空调设计中提高空气品质的方法探讨

室内空气品质的研究,已成为现代空气调节技术中的一个重要研究课题,本文通过论述空调设计对室内空气品质的影响,指出为了提高室内空气品质,空调设计应该主要从4个方面来改善,即温度和湿度、新风、气流组织和系统形式。     

Indoor Air Quality: Exploring Policy Options to Reduce Human Exposures

Deciding between the different policy approaches available for reducing human exposures to indoor pollutants is an exceptionally complex task. These options can range from waiting until more definitive information is available to enacting regulatory standards, with many variations in between. This paper presents some of the factors policy-makers must consider in establishing indoor air quality policies, and the role researchers should play in ensuring that indoor air policies are based on the best available scientific information.     

氡与室内空气环境

氡是一种放射性气体,在室内空气中广泛存在,并对人体造成极大伤害,因此倍受人们关注。本文主要介绍室内空气中氡的特性,来源,健康影响和防治措施。     

Relationships Between Ventilation and Indoor Air Quality: A Review

Abstract Adjustment of ventilation rates in buildings is widely practised, both to provide good air quality on a proactive basis and to mitigate air quality problems associated with occupant complaints. However, both cross-sectional and experimental epidemiological studies have reported mixed results and have for the most part failed to establish definitive relationships between ventilation rates and symptom prevalence or dissatisfaction with air quality. The difficulties involved in establishing such relationships may be due to a variety of confounding factors which include limitations in study design and interaction effects; difficulties in controlling ventilation rates in experimental studies; inadequate mixing of supply air in occupied spaces; high source strengths for some contaminants; dynamic interactions between sources and ventilation rates that result in increased contaminant emissions; contaminant dose-response sensory effects which are log-linear; potential contaminant generation within ventilation systems themselves; and multifactorial genesis of sick building symptoms. There is limited evidence to suggest that ventilation rate increases up to 10 L/s person may be effective in reducing symptom prevalence and occupant dissatisfaction with air quality and that higher ventilation rates are not effective. Because of complex relationships between ventilation rates, contaminant levels, and building-related health complaints/dissatisfaction with air quality, the use of ventilation as a mitigation measure for air quality problems should be tempered with an understanding of factors which may limit its effectiveness.     

室内有机化学污染防治研究现状及存在问题

指出了室内有机化学污染防治的重要性,分析了近年来国内外关于室内有机化学污染防治的研究现状,根据其中存在的问题,针对污染防治的三种方式(源头治理、改善空间传输和空气净化)提出了一些近期值得讨论和研究的问题,旨在引起相关领域研究者的共同关注,加大这些方面的研究力度,以提供解决我国室内化学污染问题的有力技术支持。     

Indoor Air Quality Investigations at Five Classrooms

Abstract Five classrooms, air-conditioned or naturally ventilated, at five different schools were chosen for comparison of indoor and outdoor air quality. Temperature, relative humidity (RH), carbon dioxide (CO₂), sulphur dioxide (SO₂), nitric oxide (NO), nitrogen dioxide (NO₂), particulate matter with diameter less than 10 mm (PM₁₀), formaldehyde (HCHO), and total bacteria counts were monitored at indoor and outdoor locations simultaneously. Respirable particulate matter was found to be the worst among parameters measured in this study. The indoor and outdoor average PM₁₀ concentrations exceeded the Hong Kong standards, and the maximum indoor PM₁₀ level was even at 472 μ;g/m³. Air cleaners could be used in classrooms to reduce the high PM₁₀ concentration. Indoor CO₂ concentrations often exceeded 1,000 μl/l indicating inadequate ventilation. Lowering the occupancy and increasing breaks between classes could alleviate the high CO₂ concentrations. Though the maximum indoor CO₂ level reached 5,900 μl/l during class at one of the sites, CO₂ concentrations were still at levels that pose no health threats.     

The Influence of Office Furniture,Workstation Layouts,Diffuser Types and Location on Indoor Air Quality and Thermal Comfort Conditions at Workstations

Abstract Many factors affect the airflow patterns, contaminant removal efficiency and the indoor air quality at individual workstations in office buildings. The effects of office furniture design and workstation layouts on ventilation performance, contaminant removal efficiency and thermal comfort conditions at workstations were studied. The range of furniture configurations and environmental parameters investigated included: 1) partition heights, 2) partition gap size, 3) diffuser types, 4) supply air diffuser location relative to the workstation, 5) return air grill location relative to the workstation, 6) heat source locations, 7) presence of furniture, 8) supply air temperatures, 9) adjacent workstations, 10) contaminant source locations, 11) supply air flow rates, and 12) outdoor air flow rates. The tracer gas technique was used to study experimentally the relative impact of these parameters on the air distribution and ventilation performance, as well as contaminant removal efficiency. Thermal environmental parameters such as air velocity and temperature were monitored at several locations to characterize the impact of these parameters on the thermal comfort conditions. The results showed that the outdoor air flow rate had a significant influence on the mean age of air. The air distributions at all the workstations were good even when the supply air flow rate was relatively low (i.e 5 L/s). At the same time, most of the parameters tested had a significant influence on contaminant removal efficiency when there was a contaminant source present somewhere in the office.     

Principles for Evaluation of Health and Comfort Hazards Caused by Indoor Air Pollution*

Abstract Consensus on simplified procedures for evaluating health consequences of occupational and outdoor exposures has existed for many years and there is no reason why a similar consensus cannot be made for normal indoor environments. A discussion of such a procedure and its limitations is the purpose of this paper. The exposure measurements should be presented to the toxicologist in the form of a list of identified compounds, concentrations of each compound reported as lifetime-integrated absorbed dose, average concentration (e.g. 24 h), peak exposures (e.g. 10–30 s), and peak exposure frequency (e.g. 90% fractile). In that perspective some of the main recommendations of this paper are that a list of compounds expected to be relevant to indoor air and the required sensitivity of the analytical procedures for these compounds must be established. These chemicals must be identified and quantified in an analysis of indoor air. Generally the investigators should pay the same interest in accurate measurements of exposure and of effects, and sampling should be made within one sampling period from measurements of health effects. The compounds of relevance to indoor air should be grouped according to the relevant toxicological principles for their evaluation. Those for which acceptable data and evaluation principles exist or can be estimated are placed on a positive list. In addition, a sub-list should be established of the remaining relevant compounds which for one or more reasons cannot be dealt with in the proposed evaluation scheme, and a consensus must be reached on the maximal acceptable fraction of compounds that cannot be toxicologically evaluated (toxicologically unknown). Finally, guidelines for evaluation of the exposures must be established including guideline values for the relevant compounds as well as procedures for sensory evaluations.     

大型商业中心室内空气品质分析及措施探讨

通过对两家采用空调系统的大型综合性商业中心的空气品质进行监测，取得大量的数据，分析了室内空气污染物浓度的影响因素，并提出了改善室内空气品质的措施。     

Indoor Climate and the Performance of Ventilation in Finnish Residences

The purpose of the study was to gather information about the actual ventilation and indoor air quality and to evaluate the differences between houses and apartments with different ventilation systems. A sample of 242 dwellings in the Helsinki metropolitan area was studied over periods of no weeks during the 1988-1989 heating season. The mean air-exchange rates had a high variation (average 0.52 l/h, range 0.07-1.55 l/h). The ASHRAE minimum value of 0.35 l/h was not achieved in 28% of the dwellings. The air-exchange rates were significantly her in the houses than in the apartments (averages 0.45/0.64 l/h, p < 0.001); in the natural ventilation systems they, were slightly her than in the mechanical systems. The average temperature in the bedrooms was approximately 22 °C (range 18–27 °C), slightly but significantly higher in the apartment than in the houses. The average dust depositions were higher in the balanced ventilation systems than in the other systems. The median radon concentration was 82 Bq/m³ (range 5-866 Bq/m³); the Finnish target value of 200 Bq/m³ was exceeded in 17% of the houses but in none of the apartment. The measurements indicate that the indoor air quality in Finnish dwellings is not always satisfactory with reference to human health and comfort.     

Indoor Air Quality Investigation on Commercial Aircraft

Abstract Sixteen flights had been investigated for indoor air quality (IAQ) on Cathay Pacific aircraft from June 1996 to August 1997. In general, the air quality on Cathay Pacific aircraft was within relevant air quality standards because the average age of aircraft was less than 2 years. Carbon dioxide (CO₂) levels on all flights measured were below the Federal Aviation Administration (FAA) standard (30,000 ppm). The CO₂ level was substantially higher during boarding and de-boarding than cruise due to low fresh air supply. Humidity on the aircraft was low, especially for long-haul flights. Minimum humidity during cruise was below the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) minimum humidity standard (20%). The average temperature was within a comfortable temperature range of 23±2°C. The vertical temperature profile on aircraft was uniform and below the International Standard Organization (ISO) standard. Carbon monoxide levels were below the FAA standard (50 ppm). Trace amount of ozone detected ranged from undetectable to 90 ppb, which was below the FAA standard. Particulate level was low for most non-smoking flights, but peaks were observed during boarding and de-boarding. The average particulate level in smoking flights (138 (ig/m3) was higher than non-smoking flights (7.6 μg/m³). The impact on IAQ by switching from low-mode to high-mode ventilation showed a reduction in CO₂ levels, temperature, and relative humidity.     

室内空气品质及其主要影响因素

介绍了人们对室内空气品质的认识和评价现状，并着重分析综述了影响室内空气品质的因素。     

空调房间3种侧送风方式下室内气流组织的数值模拟与分析

采用雷诺时均的Navier-Stokes方程与标准κ-ε双方程模型,对常用的3种侧送风方式下的办公建筑进行数值模拟,对室内空气的速度场、温度场以及空气龄进行分析,认为送回风同侧的通风方式优于送回风对侧的通风方式,可获得较高的室内空气品质。     

Indoor air quality in Portuguese schools: levels and sources of pollutants

Indoor air quality (IAQ) parameters in 73 primary classrooms in Porto were examined for the purpose of assessing levels of volatile organic compounds (VOCs), aldehydes, particulate matter, ventilation rates and bioaerosols within and between schools, and potential sources. Levels of VOCs, aldehydes, PM_2.5, PM₁₀, bacteria and fungi, carbon dioxide (CO₂), carbon monoxide, temperature and relative humidity were measured indoors and outdoors and a walkthrough survey was performed concurrently. Ventilation rates were derived from CO₂ and occupancy data. Concentrations of CO₂ exceeding 1000 ppm were often encountered, indicating poor ventilation. Most VOCs had low concentrations (median of individual species <5 μg/m³) and were below the respective WHO guidelines. Concentrations of particulate matter and culturable bacteria were frequently higher than guidelines/reference values. The variability of VOCs, aldehydes, bioaerosol concentrations, and CO₂ levels between schools exceeded the variability within schools. These findings indicate that IAQ problems may persist in classrooms where pollutant sources exist and classrooms are poorly ventilated; source control strategies (related to building location, occupant behavior, maintenance/cleaning activities) are deemed to be the most reliable for the prevention of adverse health consequences in children in schools.