Two surveys of commercial transportation environments were conducted. In the spring of 1994, environmental conditions on a variety of aircraft over 22 domestic routes were monitored. In 1996, an expanded survey of 27 travel segments was performed on Boeing 777 aircraft, interstate trains, interstate buses, short-distance commuter trains, and subways. A wide variety of environmental measurements were performed including standard Indoor Air Quality (IAQ) parameters of temperature, relative humidity and carbon dioxide (CO2). Aircraft cabin air pressure was continuously measured. Contaminants including carbon monoxide, particles, and volatile organic compounds (VOC) were monitored or sampled. Surface dust was collected using modified hand vacuums, sifted and the fine particles analyzed for fungi, bacteria, endotoxin and cat and dust mite allergens. Reasonable correlation between CO2 levels and passenger loads was observed for travel segments with variable passenger loads, such as trains and subways, which is consistent with fixed volume ventilation. CO2 levels were stable for the cruise portion of flight segments, but were significantly higher during preflight and post-flight periods, suggesting lower ventilation at times of increased passenger activity. No significant differences in total fungal concentrations were noted between any transportation modes measured in 1997 or between concentrations in transportation environments and those from living room samples collected during early spring in Boston. Cat allergen was detected in most dust samples with the highest dust mite concentrations recovered from a train. Particle concentrations were highest in subways and generally higher on all ground transportation environments than on aircraft. VOC s associated with mobile sources were higher for ground transportation than for aircraft as were many other VOCs. Exceptions were acetone and ethyl alcohol, which were higher on aircraft.
The suitability of viable and non-viable volumetric collectors as prevalence indicators for potentially allergenic airborne fungi was studied during 124 paired exposures of the Burkard (Hirst) spore trap and a modified, wind-oriented Andersen sampler. Overall, viable recoveries of several Cladosporium form species varied directly with microscopic spore counts (p less than or equal to 0.0001). However, as spore levels rose, culture plate data progressively underestimated prevailing concentrations (recoveries falling below 5% at levels above 500 spores/M3). Viable collections yielded low estimates of prevalence (20-40%) even at modest Cladosporium levels (less than 100 spores/M3) and substantially understated the abundance and regularity in air of several additional taxa. Spores typical of Penicillium and Aspergillus form species were not sought in spore trap deposits. Careful examination of these failed to reveal typical arthrospores or Fusarium macrospores despite substantial recoveries of corresponding growth in culture. Correlations in the occurrence patterns of arthrospore-forming and non-sporulating colonies with those of Coprinus and 'other basidiospores' (excluding Ganoderma) were noted.
The possible role of fungi as allergic contaminants in book collections has been investigated in eleven University of Michigan Libraries. Air in the stacks of each of the eleven libraries was sampled on three occasions (2 or 4--10 minute samples on each occasion) with Andersen Volumetric viable particle samplers. Books were handled during sampling in half the samples each day. In addition on each sampling day a location in the same building away from book storage and an outdoor location were sampled. Library spore levels were generally low. Outdoor levels consistently exceeded indoor levels. Air conditioned (AC) libraries had lower spore levels and indoor/outdoor ratios than conventionally ventilated (CV) libraries. Handling books during sampling increased spore counts in all libraries, but strikingly in CV libraries. Fungus taxa recovered were similar to those encountered in domestic interiors and outside locations in our area. The overall low spore levels and lack of a distinctive library mycoflora suggest that other sources should be sought for library-based respiratory symptoms.
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