William Fisk
Indoor Environment Program
(510) 486-5910; (510) 486-6658 fax
Recently completed analyses suggest that improving buildings and indoor environments could reduce health-care costs and sick leave and increase worker performance, resulting in an estimated productivity gain of $30 to $150 billion annually.
The research literature provides strong evidence that characteristics of buildings and their indoor environments influence the prevalence of several adverse health effects. These include communicable respiratory disease (e.g., common colds and influenza), allergy and asthma symptoms, and acute sick building syndrome (SBS) symptoms such as headaches, and irritation of the eyes, nose, throat, and skin. For example, in six studies, the number of respiratory illnesses in building occupants varied by a factor of 1.2 to 2.0 as a function of building characteristics such as rate of ventilation with outside air, type of ventilation system, and occupant density (see table). Allergy and asthma symptoms are often a consequence of indoor exposure to allergens that may originate indoors or outdoors. Several methods can be employed to reduce allergen exposures. Changeable building factors such as ventilation rates, indoor pollutant concentrations, and quality of building cleaning can influence the frequency and severity of SBS symptoms. In addition to influencing health, research suggests that the indoor environment, especially temperature and lighting, can affect worker performance directly by a fraction of a percent to a few percent.
We estimated the costs of the building-influenced adverse health effects from statistical data and published papers. The annual (1993) health-care costs for acute respiratory infections are about $30 billion. These respiratory infections result in about $35 billion in annual sick leave plus restricted activity at work. The health-care costs and productivity decreases from allergies and asthma are about $13 billion per year. Productivity losses from SBS symptoms are quite uncertain but were estimated to be around 2 percent among office workers, costing an estimated $50 billion annually.
| Setting | Populations Compared | Health Outcome | Results |
| U.S. Army Barracks | Residents of modern (low-ventilation) vs. older barracks | Respiratory illness with fever | 50% higher incidence in modern barracks |
| Finnish Office | Workers with one or more roommates vs. no roommates | Common cold | 20% more colds with roommates |
| Antarctic Station | Residents of smaller vs. larger quarters | Respiratory illness | 100% more illness in smaller quarters |
| NY state schools | Fan-ventilated vs. window-ventilated classrooms | Respiratory illness, absence | 70% more illness, 18% more absence in fan-ventilated rooms |
| Gulf War troops | Troops housed vs. never housed in different types of buildings | Symptoms of respiratory illness | Significantly more symptoms in air-conditioned building |
| U.S. jail | > 7.5 m2 vs. < 7.5 m2 space per person and high vs. low CO2 | Pneumococcal disease | Significantly higher incidence if < 7.5 m2; 95% higher incidence in high-CO2 group |
The most difficult step in the analysis was to estimate the percentage decrease in adverse health effects and the percentage of direct improvements in productivity that could be obtained by improving indoor environments. These estimates were based in part on the strength of reported associations between health effects and indoor environmental factors. The estimates also reflected the degree to which it is practical to improve relevant indoor environmental conditions such as ventilation rate and pollutant concentrations. Based on these and other considerations, we estimated the potential decreases in adverse health effects from improvements in indoor environments to be 10 to 30 percent for infectious respiratory disease, and allergy and asthma symptoms and 20 to 50 percent for SBS symptoms. The potential direct increase in office workers' performance was estimated to range between 0.5 and 5 percent. For the U.S., the corresponding annual health-care savings plus productivity gains are $6 to $19 billion from reduced respiratory disease, $1 to $4 billion from reduced allergies and asthma, $10 to $20 billion from reduced SBS symptoms, and $12 to $125 billion from direct improvements in worker performance that are unrelated to health.
Because worker salaries exceed building energy, maintenance, and annualized construction costs by a large factor, the cost-effectiveness of improvements in indoor environments will be high even when the percentage improvements in health and productivity are small. The costs of increasing ventilation and improving air filtration in a large office building were estimated and then compared to the value of projected health and productivity benefits. The resulting benefit-to-cost ratios were very high, approximately 50 to 1 and 20 to 1 for increased ventilation and improved filtration respectively.
Very strong evidence that better indoor environments can cost-effectively increase health and productivity would justify changes in building codes and in company and institutional policies related to building design, operation, and maintenance. Available data are not sufficiently specific and compelling to motivate these actions. The existing evidence of potential productivity gains is, however, clearly enough to justify an expanded program of research. A research investment on the order of $10 million per year for five years would answer many of the key questions. The total cost of this multiyear program of research would be only 0.2 percent of the most conservative estimate of annual productivity gains from improved indoor environments.
--William Fisk and Arthur Rosenfeld
William Fisk
Indoor Environment Program
(510) 486-5910; (510) 486-6658 fax
This research is supported by the DOE's, Office of Building Technology, State and Community Programs.