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INDOOR AIR QUALITY Introduction During the past decade, public concern about indoor air quality (IAQ and the "sick building syndrome" (SBS) has increased dramatically. The concern has been prompted by a variety of factors, ranging from reports of illness apparently caused by IAQ problems in individual buildings to the actions of single-issue pressure groups. Anti-smoking organizations, in particular, have sought to use IAQ/SBS issues to have smoking banned or severely restricted in public places as well as in offices. In fact, research has shown that tobacco smoke is rarely the major contributor to either poor indoor air quality or the sick building syndrome. When smoke is accumulating indoors, other substances -- including substances that cannot be seen or smelled -- are accumulating as well. In most cases, the cause is an inadequate or inadequately maintained ventilation system. Experience has shown that improved ventilation, proper filtration of the air being brought indoors and attention to system hygiene will solve even the most persistent indoor air quality problems. Environmental Tobacco Smoke and Indoor Air Quality : A variety of studies from around the world, conducted in many different settings, have confirmed that tobacco smoke in the air -- often referred to as environmental tobacco smoke (ETS) -- is typically a minor contributor to indoor air quality problems. The most pertinent research has been of three types: 1. area monitoring studies 2. personal monitoring studies 3. full building diagnostic studies l. Area monitoring studies. Such studies are conducted using stationary or fixed site monitoring equipment. Area monitoring studies have shown that the overwhelming majority of the small particles found in indoor air typically come from sources unrelated to smoking. Area studies focusing on nicotine have shown that a non-smoker, working in an office where smoking is permitted, is not likely to be exposed to the nicotine equivalent of more than about five cigarettes in an entire year. Indoor Air Quality March, 96 Page I

Area studies also have confirmed that smoking contributes very few substances to the indoor air that would not be there in any event from sources unrelated to smoking. The alternative sources include office equipment, furniture, carpeting, draperies, wall coverings and office cleaning supplies, to name only a few. 2. Personal monitoring studies. Personal monitoring studies, which require the study subjects to wear small measuring devices, have been conducted to obtain additional information on exposure by individuals. Such studies have shown that the exposures of individuals to various constituents of ETS are often below the limit of detection for the most sophisticated measuring equipment, even in workplaces in which smoking is permitted without restriction. • 3. Full building diagnostic studies. Complete building studies have been undertaken for general research purposes as well as to permit investigators to diagnose the causes of problems reported in specific buildings (i.e., so called "sick buildings"). Such studies have shown that the actual causes of the poor indoor air quality found in buildings that have been classified as "sick buildings" seldom relate to smoking or ETS. Most sick building problems (i.e., more than 90%) tend to be caused instead by inadequate ventilation and other related problems that, both alone and in combination, permit substances to accumulate in the air from all sources. Such studies also have shown that improving ventilation in buildings will reduce the level of virtually all substances found indoors and will help to eliminate sick building syndrome problems. 40 The Role of Ventilation in Improving IAQ The quality of the air indoors can be affected adversely by a wide range of substances and activities, some originating or occurring indoors and others traceable to the outside air. It also is clear that the symptoms of the sick building syndrome, such as sore eyes, a dry throat, nose irritation, fatigue, coughing, etc., have become increasingly common among office workers in many countries. The term "sick building syndrome" is relatively new. The underlying problems are, to a large extent, a function of two developments: • the energy crisis of the 1970s, which caused many building owners and operators to reduce the ventilation rate in existing buildings • the continued construction of tightly sealed buildings, coupled with failure to make provision for or actually to provide an adequate amount of ventilation Indoor Air Quality March, 96 Page 2

In many buildings, both old and new, air quality is further compromised by inadequate filtration. Poor filtration essentially means that any contaminants in the outside air -- whether from motor vehicles, factories or other sources -- will find their way indoors in largely undiluted form. In addition, poor filtration can lead over time to an accumulation of substantial quantities of dirt inside a building's air supply ducts. Combined with moisture, the dirt can act as a breeding ground for bacteria and fungi, in the building's ventilation system. Because ETS is the most visible component of the indoor air, many people attribute their discomfort or health problems to other people's smoking. The coincidence of smoking and an outbreak of symptoms is simply assumed to be causally related. The mere posting of a no-smoking sign will do little to improve indoor air quality ~ in the circumstances described above. In fact, one recent study of 3,155 office workers in 18 air conditioned offices concluded that smoking policies had no effect on the incidence of sick building syndrome complaints or symptoms. Benefits of Adequate Ventilation Many employers, building owners and building managers are reluctant to invest in improved indoor air quality because they fear increased energy and other costs. Experience has shown, however, that the costs associated with installing and maintaining improved ventilation or filtration are remarkably modest. In most cases, the costs will be more than offset by reduced absenteeism and improved productivity. . Although poor indoor air quality does not account for all absenteeism due to respiratory problems, it clearly plays a significant role. For example, a four year study of American army recruits conducted by the Walter Reed Army Hospital revealed that trainees housed in modern, energy efficient but poorly ventilated ~ barracks were approximately 50% more likely to contract a respiratory infection than were trainees housed in older, less tightly sealed buildings. Conclusions ETS is rarely the major cause of poor indoor air quality or the sick building syndrome. Most such symptoms stem from poorly maintained or inadequate ventilation and filtration systems. In the vast majority of cases, operating building ventilation systems in accordance with applicable standards is sufficient to deal with smoking as well as the other indoor air components that can accumulate in the absence of inadequate ventilation. The costs of improved ventilation and system hygiene typically are more than offset by the benefits of reduced absenteeism and improved productivity. Indoor Air Quality March, 96 Page 3