Assessment of Children’s Potential Exposure to Bioburden in Indoor Environments

Abstract

The exposure to particles and bioaerosols has been associated with the increase in health effects in children. The objective of this study was to assess the indoor exposure to bioburden in the indoor microenvironments more frequented by children. Air particulate matter (PM) and settled dust were sampled in 33 dwellings and four schools with a medium volume sampler and with a passive method using electrostatic dust collectors (EDC), respectively. Settled dust collected by EDC was analyzed by culture-based methods (including azole resistance profile) and using qPCR. Results showed that the PM2.5 and PM10 concentrations in classrooms (31.15 μg/m3 and 57.83 μg/m3, respectively) were higher than in homes (15.26 μg/m3 and 18.95 μg/m3, respectively) and highly exceeded the limit values established by the Portuguese legislation for indoor air quality. The fungal species most commonly found in bedrooms was Penicillium sp. (91.79%), whereas, in living rooms, it was Rhizopus sp. (37.95%). Aspergillus sections with toxigenic potential were found in bedrooms and living rooms and were able to grow on VOR. Although not correlated with PM, EDC provided information regarding the bioburden. Future studies, applying EDC coupled with PM assessment, should be implemented to allow for a long-term integrated sample of organic dust.

Bacterial Contamination in Health Care Centers: Differences between Urban and Rural Settings

“…The importance of applying different sampling methods allowing a more complete characterization of the exposure has already been mentioned in other studies [74][75][76], emphasizing the temporal variation as a factor to obtain a more accurate risk assessment. Thus, although there is a legal reference in Portugal on the assessment of IAQ through the use of air sampling as stand-alone method, passive methods (surface swabs, electrostatic dust cloth, vacuum settled dust and filters for HVAC systems) were also applied in this study, in order to assure a higher accuracy in the assessment of IAQ.…”

Settleable Dust and Bioburden in Portuguese Dwellings

“…The use of the passive sampling methods in this study allowed the simultaneous collection of settleable dust, for extended periods, in several homes with wide spatial coverage and without disturbing daily life [ 43 ]. A single EDC analysis is equivalent to the sum of several air-impaction measurements, with much shorter sample collection duration, permitting a more consistent estimation of exposure [ 44 ].…”

“…Sampling in parallel, and in duplicate, of settleable dust, whose sedimentation rates were gravimetrically determined according to an international standard, allowed a more accurate estimation of exposure levels inside the dwellings [ 43 ] and, together with the dwellings’ characteristics, can give indications about possible risks and assist in taking remedial measures.…”

Loading Rates of Dust and Bioburden in Dwellings in an Inland City of Southern Europe

“…The most prevalent fungal genera found in this indoor environment are Cladosporium, Penicillium, Alternaria and Aspergillus [1,2]. In fact, in Portuguese dwellings, located in the districts of Lisbon and Aveiro, Penicillium and Aspergillus have been also reported as the dominant fungi [3,4]. Lately, exposure to fungal contamination has gained increasing importance, since correlations with respiratory diseases and atopic dermatitis have been often observed [5][6][7].…”

“…Indeed, active air sampling is limited by short sampling periods (minutes to hours), representing only a snapshot of bioburden exposure [18]. Electrostatic dust collectors (EDCs) constitute a simple and cost-effective passive sampling method able to characterize bioburden present in settleable dust [3,4,[19][20][21][22][23]. Given their simplicity, low cost, independence from noisy pumps and power supply, possibility of allowing simultaneous sampling in multiple locations, and ability to provide indications of exposure over longer time frames, passive samplers are regarded as a good alternative in indoor air quality and exposure assessment studies [24,25].…”