5 Militia Drive Lexington MA 02421 Phone 781 860 9177 Fax 781 860 9178 E mail info neep orgWeb www neep org Commercial Building Indoor Air Quality An Introduction to the Problem November 1999 Prepared By Hal Levinl Building Ecology Research Group 2548 Empire Grades Santa Cruz CA 95060 9748 Phone 831 425 3946 Fax 831 426 6522 E mail hlevin cruzio com Abstract This paper provides a background on the issue of indoor air quality It includes a discussion of the financial technical legal insurance and health related aspects of unacceptable indoor air quality IAQ It discusses the roles of ventilation system performance pollutant sources and human responses in determining acceptable indoor air quality as they relate to comfort health and chronic illness Finally it discusses some issues confronting those who seek to formulate and implement policies to improve IAQ Introduction More than 3 3 billion square feet of new commercial buildings were constructed from 1988 to 1998 A 170 increase in commercial building stock is anticipated by the year 2030 That stock is expected to have a lifetime of 50 to 100 years All these buildings must provide an acceptable indoor environment to support the productivity and well being of the work force Building codes play a role in supporting the welfare of the community They protect life health and safety and also protect the investments made by bankers insurance companies businesses and individuals Finally building codes promote economic development by protecting the value of the built environment Building codes are one tool that policy makers can use to address the financial legal insurance and health related aspects of unacceptable indoor air quality The process of designing constructing starting up controlling and maintaining building systems is very complex If done properly the final product operates efficiently at reasonable cost delivering comfort safety and a healthy environment If any part of this process breaks down the product fails to deliver the benefits The health related and lost worker productivity costs from office environments amount to tens of billions of dollars per year for U S businesses Levin 1994 See Appendix C with calculations of costs for office workers Additional energy costs of 22 to 45 billion Davis 1999 are incurred annually to operate buildings due to these broken systems One key to managing the complex process of designing and efficiently operating buildings in the future lies in the ability to manage information deliver it to the proper audience and use it effectively for building design and operation Building codes and other building regulations can play a constructive role in this process and effectively promote building ventilation performance that will efficiently and economically achieve good indoor air quality Background The American Society of Heating Refrigerating and Air conditioning Engineers ASHRAE defines acceptable indoor air quality as air in which there are no known contaminants at harmful concentrations as determined by cognizant authorities and with which a substantial majority 80 or more of the people exposed do not express dissatisfaction ASHRAE Standard 62 1999 The notion that a substantial majority of the occupants do not express dissatisfaction comes directly from a tradition of thermal comfort research and ASHRAE s thermal comfort Standard 55 Ordinarily some fraction of building occupants or laboratory study subjects would like the air warmer or colder Studies show that it is virtually impossible to have less than about 7 deDear and Brager 1998 of the occupants express dissatisfaction with the thermal environment and in most cases it is more than 12 op cit As a practical goal then a maximum number of occupants expressing dissatisfaction with the thermal environment is set at 20 or stated in the Northeast Energy Efficiency Partnerships Inc Page 1 positive form no less than 80 of the occupants should be satisfied with the thermal environment The optimum thermal environment is considered to be one in which half of the occupants request a warmer environment and half request a cooler environment Historically heating ventilating and air conditioning systems were designed for thermal environmental control Air quality was usually incidental but if not it was addressed simply by injecting some amount of outdoor air into the ventilation supply The goal was to do this at the least first cost and the least operating cost The amount of outdoor air required was always determined on the basis of odor studies or control of carbon dioxide CO2 concentrations The earliest standards specified that CO2 concentrations should not exceed certain minimum levels Since those early standards a rather wide range of ventilation standards has been adopted see Appendix B Ultimately the amount of outdoor air required depends on numerous factors including the quality of the outdoor air the type and strength of sources of contaminants inside the building the occupant activities and the susceptibility of the occupant population The indoor air quality problems that draw our attention today began emerging in Europe and North America soon after the energy crisis precipitated by the Arab oil embargo of 1973 Recognition of these problems led to understanding that ventilation systems must address pollution loads as well as thermal loads Gradually more and more practitioners have agreed on the need for outdoor air to dilute indoor air contaminants and the need for both control of pollution sources and removal of point source pollution by direct exhaust to the outdoors Impacts of Unacceptable Indoor Air Quality Good or acceptable IAQ depends strongly on who must accept it There are significant differences among the needs and perspectives of building owners building occupants and public health organizations Some of these are shown in Table 1 Table 1 Three Perspectives on Acceptable IAQ Building Owners US Environmental Protection EPA Public Health Perspective Building Occupants No complaints no tenant requirements for ventilation no tenant polluting activities Minimizes exposure to toxics irritants no adverse health effects no comfort complaints Clean dry well ventilated thermally comfortable no unfamiliar or objectionable odors Unacceptable IAQ has been found to affect occupant health leading to illness and even death Airborne infectious agents such as the bacteria Tuberculosis and Legionnaire s Disease cause infection as the result of inhaling
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