indoor air quality

The well-mixing assumptions, uniform distributions of air temperatures and contaminant concentrations and neglect of air momentum effects in a zone, used in multizone airflow network models could cause errors in some cases. Through dimensional analysis of the published data from the literature, this study has found correlation between the errors and mixing levels. Our study concluded that the assumption of uniform air temperatures is not appropriate if the  vertical non-dimensional temperature gradient is higher than 0.03.

Calculating contaminant concentrations in or the required ventilation for a space has been a difficult and confusing part in the application of the IAQ Procedure of ANSI/ASHRAE Standard 62.1-2004; Ventilation for Acceptable Indoor Air Quality. Appendix D of ASRAE Standard 62 presents one method for performing these calculations, but it is limited to the steady-state analysis of a single zone. More recently, two software tools have been developed by the United States National Institute of Standards and Technology (NIST) to facilitate these calculations and to include transient effects.

Scientific studies have linked particulate matter with a series of significant health problems. In ventilation systems, indoor particle concentration and dust load on air duct surfaces are two concerns for human health. PROBE-PM (Predicting code for building environment-particulate matter transport simulation), a code to simulate the particle transport in the whole ventilation system is developed.

A new concept, the spatial flow influence factor (SFIF), put forward by us in our previous paper, provides a new insight into the airflow structure. In this paper, several typical illustrative examples are presented to show: (1) how to optimally arrange the chemical pollutant sources and the occupied regions for a given indoor airflow; (2) how to optimize the position of adsorption materials. From the examples,  it is seen that the concept is powerful in the control of indoor air gas pollutants.

In this study, the characteristics of the movement of chemical compounds in the concealed spaces and indoor spaces in houses were investigated using building cut models and a simulation program Fresh2006. The equivalent leakage areas in the concealed spaces were measured using cut models of wooden structures: a common wooden structure, an improved wooden structure and a wooden (2 inch x 4 inch) stud structure.

Traffic–related pollutant has been recognized as an air pollution hot spot due to its large emission rate and great health impacts for the exposed population. In the present investigation, a computational fluid dynamics technique is used to evaluate the effect of traffic pollutions on indoor air quality of a naturally ventilated building. The transport of street-level nonreactive pollutants emitted from motor vehicles into the indoor environment is simulated using the RNG k-ε model of the turbulent flows and the pollutant transport equations.

Building indoor environment quality (IEQ) has received growing attentions lately because of the extended time people spend indoors and the increasing reports of health problems related to poor indoor environments. Recent alarms to potential terrorist attacks with airborne chemical and biological agents (CBA) have further highlighted the research needs on building vulnerability and protection.

As strategies for improving building envelope and HVAC equipment efficiencies are increasingly required to reduce building energy use, a greater percentage of energy loss will occur through building envelope leakage. Although the energy impacts of unintended infiltration on a building's energy use can be significant, current energy simulation software and design methods are generally not able to accurately account for envelope infiltration and the impacts of improved airtightness.

Owing to the growing concern about indoor air quality (IAQ) globally in hospitals, especially after the recent outbreak of diseases like severe acute respiratory syndrome (SARS), Swine Flu (H1N1) and other airborne infections such as Tuberculosis, the quest for energy efficient ventilation system is growing. To provide acceptable indoor air quality that is capable of removing indoor air contaminants in hospital wards, sustainable ventilation strategy is required.

The indoor environment and occupants’ health of approximately 5,000 residential buildings were investigated by a questionnaire covering entire Japan. The purpose of this survey is to clarify the association between indoor air pollution and adverse health effect, and to study effective ways of keeping indoor air clear with ventilation systems in house. Questionnaires were distributed to 7,812 occupants living in a house with a mechanical ventilation system across 47 Prefectures in Japan on February 2012 using internet survey web site.