Variabilities in aerosolizing activities and airborne fungal concentrations in a bakery

Fungal spores: a critical review of the toxicological and epidemiological evidence as a basis for occupational exposure limit setting

Fungal spores are ubiquitous in the environment. However, exposure levels in workplaces where mouldy materials are handled are much higher than in common indoor and outdoor environments. Spores of all tested species induced inflammation in experimental studies. The response to mycotoxin-producing and pathogenic species was much stronger. In animal studies, nonallergic responses dominated after a single dose. Allergic responses also occurred, especially to mycotoxin-producing and pathogenic species, and after repeated exposures. Inhalation of a single spore dose by subjects with sick building syndrome indicated no observed effect levels of 4 x 10(3) Trichoderma harzianum spores/m(3) and 8 x 10(3) Penicillium chrysogenum spores/m(3) for lung function, respiratory symptoms, and inflammatory cells in the blood. In asthmatic patients allergic to Penicillium sp. or Alternaria alternata, lowest observed effect levels (LOELs) for reduced airway conductance were 1 x 10(4) and 2 x 10(4) spores/m(3), respectively. In epidemiological studies of highly exposed working populations lung function decline, respiratory symptoms and airway inflammation began to appear at exposure levels of 10(5) spores/m(3). Thus, human challenge and epidemiological studies support fairly consistent LOELs of approximately 10(5) spores/m(3) for diverse fungal species in nonsensitised populations. Mycotoxin-producing and pathogenic species have to be detected specifically, however, because of their higher toxicity.

Temporal variation of airborne fungi concentrations and related factors in subway stations in Seoul, Korea

This study was performed to assess the levels of fungi concentration in subway stations in Seoul, Korea, and to investigate factors contributing to these concentrations. Ninety air samples were collected hourly over the course of a day from five different subway stations. In addition, five settled dust samples and 12 stagnant water samples were collected to investigate these as potential sources of fungi contamination. The number of passengers and frequency of passing trains were also determined during the sampling periods, as they were considered potential factors influencing the airborne fungi concentrations at a given time during the day. The airborne fungi concentrations, as a function of time, were log-normally distributed. The airborne fungi concentrations measured during the morning and evening commute hours (during which the number of passengers and frequency of passing trains was highest) were significantly higher than those measured during non-commute hours. High concentrations of fungi were found in the settled dust samples, suggesting that the settled dust may have been the main source of airborne fungi concentration. The air movement generated mainly by passengers and additionally by trains might have played a role in suspending the fungi from the settled dust. It was also found that stagnant water might be a potential source of airborne fungi.

An update on pollen and fungal spore aerobiology

Changes in climate are altering pollen distribution. Predictive modeling can be used to forecast long- and short-term changes in pollen concentrations. Increasing evidence confirms the presence of pollen allergens on small, respirable particles in the air, explaining the occurrence of pollen-season increases in asthma. Like pollens, aboveground indoor fungal aerosols primarily reflect outdoor concentrations. Basement spore concentrations might be higher and reflective of local sources. Fungal presence in the indoor or outdoor air can be monitored on an area basis or with personal monitors. The samples can be analyzed by means of microscopy, culture, DNA probes, HPLC, or immunodetection. Total fungal biomass can be estimated on the basis of measurements of ergosterol or glucan in environmental samples. Unfortunately, there are no generally accepted standards for interpretation of fungal levels in indoor or outdoor air. At present, the best approach to indoor fungal control is moisture control in the indoor environment. This will essentially prevent fungal growth, except from extraordinary events.