Biological contaminants —illness syndromes; bacteria; viruses; and exposures to insect, mite, and animal allergens - Indoor Environmental Quality - page 151

Table 5.2 Major Infectious Diseases

Associated with Viral Aerosols
Disease Virus type

Influenza Orthomyxovirus

Cold Coronavirus

Measles Paramyxovirus

Rubella Togavirus

Chicken pox Herpes virus

Respiratory infection Adenovirus

transmitted through air are summarized in Table 5.2 . The airborne nature of
the transmission of flu, cold, and respiratory infection viruses explains the
high attack rates of these diseases, particularly in high-population-density
environments such as schools and office buildings.
Viruses mutate readily. Therefore, new virulent forms of cold and flu
viruses appear, and permanent immunity does not occur as a consequence
of a single infection. Primary risk factors are susceptible hosts; the presence
of an infected individual with an active case of the disease; the proximity of
potential hosts and an infectious aerosol source; and, in many buildings,
inadequate ventilation.

III. Settled organic dust

Settled floor and other surface dust has been implicated as a potential causal
factor for sick building-type symptoms (SBS) by European investigators. The
component of surface dusts that appears to be closely associated with SBS
is described as macromolecular organic dust (MOD). This dust appears to
be immunogenic, consisting of proteins, DNA, and other large molecules of
biological origin. Modified human serum albumin appears to comprise the
major portion of MOD.
Settled dust is an apparent source of volatile organic and semivolatile
organic compounds (VOCs and SVOCs), including aldehydes (C

-C ) and

2 11

carboxylic acids. Microbial decomposition of lipids or synthesis has

been suggested as the origin of microbial VOC (MVOC) emissions from
settled dust. Significant associations between surface dust MVOC emissions
and symptoms of mucous membrane irritation and difficulty concentrating
have been reported ( Table 5.3 ) . A strong correlation between compounds
emitted from MOD and mucous membrane symptoms among occupants of
office buildings has also been reported.

de nova

IV. Mites

Exposure to house dust mite allergens has been reported to be the major
cause of chronic allergic rhinitis, asthma, and atopic dermatitis in North
America and Europe. The prevalence of mite sensitization among asthmatic