Microbiological air sampling was performed in one fiberboard factory and two
chipboard factories located in south-eastern Poland. It was found that the
levels of bacteria, fungi, dust and bacterial endotoxin in the air of examined
facilities were high during initial stages of the production cycle (shredding of
waste wood, storing of chips) and then sharply decreased during further stages
of this cycle (forming and formatting of the boards). In the fiberboard factory,
the concentration of airborne microorganisms at the initial stages of production
cycle was 71.8-95.2 × 10³ cfu/m³ and dropped in further
stages to the level of 8.4-17.5 × 10³ cfu/m³. Fungi
(mostly Aspergillus fumigatus and Penicillium spp.) were prevailing
microorganisms in the air of the fiberboard factory, forming 46.0-87.3% of the
total airborne microflora. The concentrations of microorganisms in the air of
the chipboard factories were significantly lower compared to the fiberboard
factory (p < 0.05). During initial stages of production cycle they were
within the range of 12.9-101.5 × 10³ cfu/m³, while during
forming and formatting of boards within the range of 5.3-12.4 × 10³
cfu/m³. On average, the most common microorganisms in the air of the
chipboard factories were corynebacteria (mostly Arthrobacter spp. and
Corynebacterium spp.) which formed 24.4-64.6% of the total microflora. The
values of the respirable fraction of airborne microflora in the fiberboard and
chipboard factories varied within a fairly wide range and were between
20.5-91.1%. Altogether, 38 species or genera of bacteria and 16 species or
genera of fungi were identified in the air of examined factories, of which
respectively 14 and 9 species or genera were reported as having allergenic
and/or immunotoxic properties. The concentration of bacterial endotoxin in the
air of examined factories was greatest, similarly to the concentration of
microorganisms, during the initial stages of the production cycle: 103.1-1974.0
EU/m³ in the fiberboard factory, and 3.2-217.4 EU/m³ in
chipboard factories. In conclusion, the workers of fiberboard and chipboard
factories may be exposed during the initial stages of the production cycle
(shredding of waste wood, storing of chips) to high levels of airborne
microorganisms and endotoxin posing respiratory hazard.