410 Energy Project Financing: Resources and Strategies for Success
Ozone is brought into buildings with outdoor air. Certain types of
office equipment, such as photocopy machines and laser printers, can
also be a source of indoor ozone. Ozone causes pulmonary inflammation
and other pulmonary health effects. Ozone is removed from indoor air
by reaction with indoor surfaces; thus indoor ozone concentrations are
usually lower than outdoor concentrations. If indoor sources of ozone
are limited, increasing the ventilation rate, while decreasing concentra-
tions of indoor-generated pollutants, will usually increase the indoor
ozone concentration.
In addition to the direct effects of ozone on health, ozone can react
chemically with VOCs in the indoor air or with surface materials. These
reactions may produce VOCs that may be a source of chemical irritation
(Weschler and Schields 1997).
Moisture is not a pollutant but it has a strong influence on indoor
environmental quality. Water vapor is generated indoors due to human
metabolism and human activities involving water use, as well as due to
unvented combustion activities and by humidifiers. Moist soil may be a
source of moisture in indoor air and in the flooring materials that contact
the soil. The implications of high humidity for human health are complex
and still a subject of debate (Baughman and Arens 1996, Arens and Baugh-
man 1996). In some situations, high relative humidities may contribute to
growth of fungi and bacteria that can adversely affect health.
Condensation of water on cool indoor surfaces (e.g., windows)
may damage materials and promote the growth of microorganisms.
Water leaks, such as roof and plumbing leaks, and exposure of building
materials to rain or snow during building construction are a frequent
source of material damage and growth of microorganisms. There is
quite strong evidence that moisture problems in buildings lead to ad-
verse respiratory health effects such as a higher prevalence of asthma
or lower-respiratory-tract symptoms (e.g., Brunekreef 1992, Dales et al.
1991, Spengler et al. 1993; Smedje et al. 1996, Division of Respiratory
Disease Studies 1984). There are many case studies of moisture-related
microbiological problems in commercial buildings. The presence of
humidifiers in commercial building HVAC systems has been associated
with an increase in various respiratory health symptoms.
Particles are present in outdoor air and are also generated indoors
from a large number of sources (Owen et al. 1992) including tobacco
smoking and other combustion processes. Some particles and fibers may
be generated by indoor equipment (e.g. copy machines and printers).