Bioaerosols - Aerosols: Measurement, Dosimetry, and Health Effects - page 326

HPLC have been used to detect metabolic activity of fungi and actinomycetes on building mate-
rials in a test chamber. 227 Activity occurred at 90%-99% RH, and the main measurable VOCs
were 3-methyl-1-butanol, 1-pentanol, 1-hexanol, and 1-octen-3-ol. Ventilation system ilters colo-
nized with fungi have been found to release acetone, hexane, and organic compounds that uncolo-
nized ilters did not emit. 226 Selected VOCs have been monitored in cleaned, looded homes and an
unlooded residence as possible indicators of fungal metabolism. 403 Three alcohols and one ketone
were detected in signiicant concentrations in some looded homes (70-2700 ng/m 3 ), the most com-
mon being 3-methyl-1-butanol along with 2-octen-1-ol, 2-heptanone, and 1-octen-3-ol. However,
MVOC levels did not correlate with bacterial or fungal concentrations and could not be linked to
speciic sources or used to quantify microbial air concentration.
The sugar alcohol mannitol has been suggested as a suitable molecular tracer for basidiospores
and PM potassium for ascospores. 141 Mannitol concentration also has been used as a biotracer in a
global model simulation of PBAP from fungi (GEOS-Chem). 142 Proteins are characteristic of par-
ticles of biological origin and have been measured in indoor and outdoor air with a bicinchoninic
acid assay. 156,157 Algal toxins (e.g., brevitoxins from K. brevis ) have been measured with LC-MS. 134
12.6.4.6 Molecular Genetic Assays
Molecular genetic techniques have received increased attention as diagnostic tools in the study of
airborne microorganisms and can provide genus-, species-, or strain-speciic identiication. These
procedures allow precise detection and quantiication of speciic organisms or genes. PCR assays
amplify target nucleic acid sequences. Genus- and species-speciic nucleic acid probes have been
designed that can be used for microscopic visualization. 404 PCR-based methods have been used
to detect bacteria on contaminated surfaces, 405 L. pneumophila in ilter and impinger samples, 406
M. tuberculosis in air samples from patient isolation rooms, 407 the aerodynamic size range of
airborne mycobacteria associated with whirlpools, 408 and Penicillium roquefortii in a miniature
cyclone sampler. 409 Solid-phase PCR from iltered impinger samples was found to be more sensitive
than a cultivation-based method for aerosolized Escherichia coli . 410 Bacterial CpG DNA has been
analyzed using quantitative PCR speciic for bacterial ribosomal RNA. 411
Mold-speciic PCR (MQPCR) has been applied in various environments, including homes,
schools, and hospitals. 85,299,412-414 Assays have been developed for >130 fungal species, and the
method is based on the detection of pre-selected species groups. A panel of 36 indicator fungi has
been proposed for quantitative evaluation of mold burden in U.S. homes. 415 Other molecular genetic
methods such as cloning and sequencing or denaturing gradient gel electrophoresis (DGGE) have
been used as research tools to investigate dynamic changes in microbial community diversity. Such
methods have been employed to characterize microbial contaminants in MWFs, 416 track microor-
ganisms aerosolized from loodwater, 417 examine the diversity of indoor bacterial communities, 418
and compare microbial composition in indoor and outdoor environments. 419
12.7 CONCLUDING REMARKS
Particles of microbial, plant, and animal origin cover a wide range of sizes and deposit in all regions
of the human airways. Some of the respiratory effects of bioaerosol exposure are similar to reac-
tions to other inlammatory particles, but certain responses are unique, for example, infection as
a result of microbial multiplication after inhalation. The economic burden of bioaerosol-related
diseases in the community and workplaces is very great, but public health management of new and
reemergent infectious diseases requires national and international cooperation. Increased support
of research on the aerosol transmission of infectious agents, exposure measurement, engineering
controls, personal protection, and clean-up procedures is expected to beneit other areas of public
health preparedness as well.
Occupational risk assessment studies of bioaerosols have been limited by the lack of accepted
reference values for speciic agents other than those for which occupational exposure limits have