According to the EPA poor indoor air quality may create illness among workers, as well as a decrease in productivity. Even a well-maintained building can experience periods of poor air quality which could affect employees. There are measures you can take, both as an employee and as an office manager/tenant. For example, cleaning up water spills helps avoid the growth of mold/fungi.
The Video On Demand training, Indoor Air Quality, provides and understanding of the circumstances surrounding poor air quality. Employees learn how to recognize the signs of existing problems, while taking measure to prevent new issues.
The Indoor Air Quality website, from the EPA, provides specific information on hazards, as well as the effects they have on people.