Phase 2 of the California Healthy Building Study: A Status Report

The primary goal of the California Healthy Building Study (CHBS) is to identify the major characteristics of buildings, ventilation systems, jobs, and indoor environmental quality that are associated with building-related sick-building health symptoms. The first phase of the CHBS was a cross sectional study of 12 office buildings located in the San Francisco Bay area. Health symptom and job data were collected via a questionnaire, buildings and ventilation systems were characterized, and regression models were used to assess associations between symptom prevalences and factors suspected to be associated with increased symptoms. This report summarizes research activities undertaken during Phase-2 of the CHBS and compiles currently available results. Phase 2 activities were limited to inspections and low cost measurements that yielded additional information that could be used in conjunction with the Phase-1 symptom data or provided valuable experience or information for future research. Because much of the Phase-2 effort was devoted to evaluation of measurement methodologies or collection of information that will be used in conjunction with the Phase-1 symptom data, this report is intended primarily for internal use by the CHBS research team. The Phase-2 study included the following components: (1) inspections of HVAC systems to identify and, in some cases, quantify potential sources of volatile organic compounds, fibers, and bioaerosols; (2) evaluation of a protocol for measuring the concentration of bioaerosols in the air exiting supply air diffusers; (3) interviews of building operators to assess practices related to HVAC inspection, cleaning, and disinfecting; (4) evaluation of a protocol for measuring the extent of microbiological contamination on floors and on upholstered chairs; (5) quantifying the amount of carpet within each study space in order to allow an improved assessment of associations with worker symptoms; (6) interviews of building operators to determine the quality of office cleaning and the nature of office pest-control practices; (7) measurement of the spatial and temporal variations in sound levels within study areas so that a protocol for sound-level measurements could be designed and used in a future study; and (8) measurement of percent lighting flicker in each study space so the association between percent flicker and symptoms could be evaluated. Regression modeling to evaluate associations between Phase-1 symptom prevalences and Phase-2 data is ongoing and is not described in this document.