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Title: Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities

Abstract

Chemical processes taking place in indoor environments can significantly alter the nature and concentrations of pollutants. Exposure to secondary contaminants generated in these reactions needs to be evaluated in association with many aspects of buildings to minimize their impact on occupant health and well-being. Focusing on indoor ozone chemistry, we describe alternatives for improving indoor air quality by controlling chemical changes related to building materials, ventilation systems, and occupant activities.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org.:
Environmental Energy Technologies Division
OSTI Identifier:
1010622
Report Number(s):
LBNL-60291
TRN: US201108%%501
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Conference
Resource Relation:
Conference: HB 2006 Conference, Lisbon, Portugal, June 4-8, 2006
Country of Publication:
United States
Language:
English
Subject:
54; AIR QUALITY; BUILDING MATERIALS; CHEMISTRY; FOCUSING; INDOORS; OCCUPANTS; OZONE; POLLUTANTS; VENTILATION SYSTEMS

Citation Formats

Morrison, G.C., Corsi, R.L., Destaillats, H., Nazaroff, W.W., and Wells, J.R. Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities. United States: N. p., 2006. Web.
Morrison, G.C., Corsi, R.L., Destaillats, H., Nazaroff, W.W., & Wells, J.R. Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities. United States.
Morrison, G.C., Corsi, R.L., Destaillats, H., Nazaroff, W.W., and Wells, J.R. Mon . "Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities". United States. doi:. https://www.osti.gov/servlets/purl/1010622.
@article{osti_1010622,
title = {Indoor Chemistry: Materials, Ventilation Systems, and Occupant Activities},
author = {Morrison, G.C. and Corsi, R.L. and Destaillats, H. and Nazaroff, W.W. and Wells, J.R.},
abstractNote = {Chemical processes taking place in indoor environments can significantly alter the nature and concentrations of pollutants. Exposure to secondary contaminants generated in these reactions needs to be evaluated in association with many aspects of buildings to minimize their impact on occupant health and well-being. Focusing on indoor ozone chemistry, we describe alternatives for improving indoor air quality by controlling chemical changes related to building materials, ventilation systems, and occupant activities.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2006},
month = {Mon May 01 00:00:00 EDT 2006}
}

Conference:
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  • The Washington State Ventilation and Indoor Air Quality Code (VIAQ) has required the installation of whole house ventilation systems in all new homes since July 1991. A variety of systems are allowed by the VIAQ. In May 1998, a survey was conducted to explore occupant interaction with the code mandated systems. The survey is part of a research project designed to explore the effectiveness of the VIAQ. This paper examines the data collected from a survey of 235 Washington State residents living in homes affected by the ventilation requirements. During a 10 minute telephone interview, respondents were asked about repairmore » records, alterations, inconveniences, and benefits of their whole house ventilation systems. The study reveals that people are concerned about indoor air quality, and believe fresh air is important for health. However, they do not operate their ventilation systems near as much as recommended (3.4 hours on average compared to 8 hours per day recommended) and when they adjust their systems, they adjust them to provide even less fresh air. Over 99% of the people surveyed believed the air in their homes was good or average. People who have problems with the systems, such as noise, drafts and/or energy waste, use their systems less than other people. While people who have code mandated ventilation systems are typically not aware of all the systems components, 64% of those with ventilation systems say they would install the same system again.« less
  • The functioning of an active sub-slab ventilation system (SVS) has been studied successfully with the help of a previously evaluated numerical model. The parameters explored are the permeability of the sub-slab and the gravel placed beneath it, the amplitude of applied pressure at the installation point of the system and the functioning method: depressurization or pressurization. The mechanisms contributing to the success of the two systems are identified. This numerical study shows that the presence of a layer of gravel beneath the sub-slab considerably improves the performance of the SVS. Considered separately from the extremely permeable sub-slabs, the depressurization systemsmore » perform better than the pressurization systems. 17 refs. [Francais] Le fonctionnement des Systemes de Ventilation active du Sol (SVS) a ete etudie a l`aide d`un outil numerique precedemment evalue avec succes. Les parametres explores sont les permeabilites du sol et du gravier place sous plancher bas, l`amplitude de la pression appliquee au point d`installation du systeme, et le mode de fonctionnement: Depressurisation ou Pressurisation. Les mecanismes contribuant au succes des deux systemes sont identifies. Cette etude numerique montre que la presence d`une couche de gravier sous plancher bas ameliore de facon considerable les performances des SVS. Mis a part le cas des sols extremement permeables, les systemes de Depressurisation ont de meilleures performances que les systemes de Pressurisation. 17 refs.« less
  • Through mass-balance modeling of various ventilation scenarios that might satisfy the ASHRAE 62.1 Indoor Air Quality (IAQ) Procedure, we estimate indoor concentrations of contaminants of concern (COCs) in California “big box” stores, compare estimates to available thresholds, and for selected scenarios estimate differences in energy consumption. Findings are intended to inform decisions on adding performance-based approaches to ventilation rate (VR) standards for commercial buildings. Using multi-zone mass-balance models and available contaminant source rates, we estimated concentrations of 34 COCs for multiple ventilation scenarios: VRmin (0.04 cfm/ft2 ), VRmax (0.24 cfm/ft2 ), and VRmid (0.14 cfm/ft2 ). We compared COC concentrationsmore » with available health, olfactory, and irritant thresholds. We estimated building energy consumption at different VRs using a previously developed EnergyPlus model. VRmax did control all contaminants adequately, but VRmin did not, and VRmid did so only marginally. Air cleaning and local ventilation near strong sources both showed promise. Higher VRs increased indoor concentrations of outdoor air pollutants. Lowering VRs in big box stores in California from VRmax to VRmid would reduce total energy use by an estimated 6.6% and energy costs by 2.5%. Reducing the required VRs in California’s big box stores could reduce energy use and costs, but poses challenges for health and comfort of occupants. Source removal, air cleaning, and local ventilation may be needed at reduced VRs, and even at current recommended VRs. Also, alternative ventilation strategies taking climate and season into account in ventilation schedules may provide greater energy cost savings than constant ventilation rates, while improving IAQ.« less
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  • This report considers the question of whether the California Energy Commission should incorporate the ASHRAE 62.1 ventilation standard into the Title 24 ventilation rate (VR) standards, thus allowing buildings to follow the Indoor Air Quality Procedure. This, in contrast to the current prescriptive standard, allows the option of using ventilation rate as one of several strategies, which might include source reduction and air cleaning, to meet specified targets of indoor air concentrations and occupant acceptability. The research findings reviewed in this report suggest that a revised approach to a ventilation standard for commercial buildings is necessary, because the current prescriptivemore » ASHRAE 62.1 Ventilation Rate Procedure (VRP) apparently does not provide occupants with either sufficiently acceptable or sufficiently healthprotective air quality. One possible solution would be a dramatic increase in the minimum ventilation rates (VRs) prescribed by a VRP. This solution, however, is not feasible for at least three reasons: the current need to reduce energy use rather than increase it further, the problem of polluted outdoor air in many cities, and the apparent limited ability of increasing VRs to reduce all indoor airborne contaminants of concern (per Hodgson (2003)). Any feasible solution is thus likely to include methods of pollutant reduction other than increased outdoor air ventilation; e.g., source reduction or air cleaning. The alternative 62.1 Indoor Air Quality Procedure (IAQP) offers multiple possible benefits in this direction over the VRP, but seems too limited by insufficient specifications and inadequate available data to provide adequate protection for occupants. Ventilation system designers rarely choose to use it, finding it too arbitrary and requiring use of much non-engineering judgment and information that is not readily available. This report suggests strategies to revise the current ASHRAE IAQP to reduce its current limitations. These strategies, however, would make it more complex and more prescriptive, and would require substantial research. One practical intermediate strategy to save energy would be an alternate VRP, allowing VRs lower than currently prescribed, as long as indoor VOC concentrations were no higher than with VRs prescribed under the current VRP. This kind of hybrid, with source reduction and use of air cleaning optional but permitted, could eventually evolve, as data, materials, and air-cleaning technology allowed gradual lowering of allowable concentrations, into a fully developed IAQP. Ultimately, it seems that VR standards must evolve to resemble the IAQP, especially in California, where buildings must achieve zero net energy use within 20 years.« less