People are exposed to pollutants present in indoor air, in dust, and on indoor surfaces. The Indoor Environment Group investigates how large these exposures are through measurements in sets of buildings and exposure modeling. The Group also investigates how exposures are affected by:
- the types of materials and products used in the building and in the building's furnishings and equipment;
- the rates and methods of ventilation;
- the patterns of indoor airflow;
- the use of various types of filtration systems for removing particles and gaseous pollutants;
- temperature and humidity,
- indoor chemical reactions, and
- occupant behaviors such as direct use of various sources of pollutants, cooking and operation of range hoods, and activities that re-suspend particles from surfaces.
The Indoor Environment Group also investigates how exposures to air pollutants and related features of buildings affect people's health and work and school performance. The Group performs epidemiologic studies in samples of buildings to determine how indoor environmental factors affect health symptoms, absence rates, and aspects of work performance. Changes, or interventions, are made in buildings to modify indoor environmental factors and exposure and health data are collected before and after the interventions. Statistical analyses indicate how the interventions affect health and absence. Some intervention studies are also performed using people in laboratory chambers with very tightly-controlled environmental conditions. Risk analysis is also used to estimate how exposures to various pollutants affects the risks of chronic adverse health effects and to identify the most important pollutants.
The Group also has a strong record of critical reviews and statistical meta-analyses of published data to determine how various factors affect health and work performance. Examples include meta analyses of how dampness and mold in homes influence adverse respiratory health effects and respiratory infections, an evaluation of how ventilation rates in offices influence prevalence rates of sick building symptoms, and critical reviews of how air conditioning and air cleaning affect health. When feasible, quantitative relationships between risk factors and health and performance outcomes are derived from statistical analyses of our published data and expressed as equations illustrated through curves on charts. Additionally, the Group estimates the economic costs of indoor environmental exposures and the costs and economic benefits of undertaking various measures to improve indoor environmental quality.