Bioaerosols - Aerosols: Measurement, Dosimetry, and Health Effects - page 286

12.6 Environmental Measurement and Analytical Techniques.................................................... 317
12.6.1 Exposure Assessment ............................................................................................... 317
12.6.2 Bioaerosol Measurement .......................................................................................... 317
12.6.3 Bioaerosol Samplers ................................................................................................. 317
12.6.3.1 Inertial Sampling ....................................................................................... 317
12.6.3.2 Filtration..................................................................................................... 322
12.6.3.3 Electrostatic Precipitation .......................................................................... 322
12.6.3.4 Future Directions in Bioaerosol Sampling ................................................ 323
12.6.4 Sample Analysis ....................................................................................................... 323
12.6.4.1 Microscopy ................................................................................................ 323
12.6.4.2 Cultivation-Based Methods for Viruses, Bacteria, and Fungi ................... 324
12.6.4.3 Biological Assays ....................................................................................... 324
12.6.4.4 Immunoassays............................................................................................ 325
12.6.4.5 Chemical Assays........................................................................................ 325
12.6.4.6 Molecular Genetic Assays ......................................................................... 326
12.7 Concluding Remarks ............................................................................................................ 326
References...................................................................................................................................... 327
12.1 INTRODUCTION
Bioaerosols are those airborne particles that originated from living organisms (e.g., bacteria, pro-
tists, plants, fungi, and animals) or that depend on living organisms (e.g., viruses). Bioaerosols
may consist of entire microscopic structures, for example, viruses, intact bacterial cells and spores,
protozoa and their cysts, fungal cells and spores, and plant pollen grains and spores. Cell fragments
may be present in indoor and outdoor air and are also considered bioaerosols, for example, airborne
particles of decayed microbial, plant, and animal matter; wood and grain dusts; the droppings and
dried body parts of arthropods; and particles of larger animal skin, saliva, feces, and urine. The
term biological agent refers to any substance of biological origin that is capable of producing an
effect on humans, for example, infectious agents, bacterial DNA, peptidoglycans, endotoxin, exo-
toxins, mycotoxins, and (1 → 3)-β-d-glucans and allergens from bacteria, pollen, fungi, dust mites,
cockroaches, and so forth. Bioaerosols may elicit responses similar to those caused by nonbiogenic
particles (e.g., a hypersensitivity, irritant, or inlammatory response) as well as unique reactions
(e.g., infectious diseases and toxicoses). The respiratory tract responds to injury, including that
caused by biological agents, in a limited number of ways, for example, rhinosinusitis, pharyngi-
tis, laryngitis, upper airway obstruction, alveolitis, pulmonary edema, asthma, chronic obstructive
pulmonary disease (COPD), bronchitis, and pulmonary infection. 1 Bioaerosols occur as airborne
particles in a size range of ∼0.02-100 μm; thus, different cells, spores, pollen grains, and biological
fragments may deposit in all regions of the human airways. Smaller bioaerosols remain airborne
for longer periods and travel further distances, which makes it possible for one person in a shared
space to expose a large number of individuals to an infectious agent. Microorganisms, plants, and
animals are important components of surface waters and soil. Although not particulate in form,
plants and animals release gases and vapors, for example, oxygen, carbon dioxide, methane, and
water. Emissions from microorganisms (microbial volatile organic compounds [MVOCs]) account
for the earthy smell that follows a rain shower or comes from freshly turned garden soil. The distinc-
tive lavors of certain foods and beverages as well as the less pleasant aromas of decay, body odor,
and moldy buildings are also volatile microbial metabolites. The complex interactions of MVOCs
and bioaerosols with other airborne particles are seldom studied but are likely important for a com-
prehensive understanding of the effects of biological agents on human health and comfort. While it
is impossible to cover this broad topic in great depth in a single chapter, we discuss health effects,
dosimetry, and bioaerosol measurement with illustrations and examples from the vast literature on
the subject.