ABSTRACT
INTRODUCTION Bioaerosols in indoor environments comprise a range of microscopic biological particles of animal, plant and microbial origin that can be inhaled and impinge on human health. Allergenic animal particulates include dander and dried saliva of pets, such as cats and dogs, and other furred animals; fragments of insects such as cockroaches, fleas and clothes moths; fragmented bodies and faeces of storage and house dust mites; and amoebae and other unicells belonging to the Protozoa. Plant particulates include unicellular algae and fragments of multicellular algal filaments; spores of lower plants such as mosses and ferns; and minute fragments and whole pollen grains of higher plants, which are discussed in Chapter 1.3. Although protozoans and unicellular algae are microorganisms, the most medically important microbial particulates in indoor air belong to neither of these groups, but are the cells and spores of fungi and bacteria, and viruses. In this chapter, the different categories of microorganism (including algae and protozoa) present in indoor air are described in general terms. Because of the diversity of forms, fungi are dealt with in more detail than the other categories. Where the health implications of individual groups are not dealt with in detail in later chapters, they are discussed briefly here.
