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Evaluation of sampling methods for toxicological testing of indoor air particulate matter.

ABSTRACT: There is a need for toxicity tests capable of recognizing indoor environments with compromised air quality, especially in the context of moisture damage. One of the key issues is sampling, which should both provide meaningful material for analyses and fulfill requirements imposed by practitioners using toxicity tests for health risk assessment. We aimed to evaluate different existing methods of sampling indoor particulate matter (PM) to develop a suitable sampling strategy for a toxicological assay. During three sampling campaigns in moisture-damaged and non-damaged school buildings, we evaluated one passive and three active sampling methods: the Settled Dust Box (SDB), the Button Aerosol Sampler, the Harvard Impactor and the National Institute for Occupational Safety and Health (NIOSH) Bioaerosol Cyclone Sampler. Mouse RAW264.7 macrophages were exposed to particle suspensions and cell metabolic activity (CMA), production of nitric oxide (NO) and tumor necrosis factor (TNF?) were determined after 24?h of exposure. The repeatability of the toxicological analyses was very good for all tested sampler types. Variability within the schools was found to be high especially between different classrooms in the moisture-damaged school. Passively collected settled dust and PM collected actively with the NIOSH Sampler (Stage 1) caused a clear response in exposed cells. The results suggested the higher relative immunotoxicological activity of dust from the moisture-damaged school. The NIOSH Sampler is a promising candidate for the collection of size-fractionated PM to be used in toxicity testing. The applicability of such sampling strategy in grading moisture damage severity in buildings needs to be developed further in a larger cohort of buildings.

SUBMITTER: Tirkkonen J

PROVIDER: S-EPMC5015124 | biostudies-literature | 2016 Sep

REPOSITORIES: biostudies-literature

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Evaluation of sampling methods for toxicological testing of indoor air particulate matter.

Tirkkonen Jenni J Täubel Martin M Hirvonen Maija-Riitta MR Leppänen Hanna H Lindsley William G WG Chen Bean T BT Hyvärinen Anne A Huttunen Kati K

Inhalation toxicology 20160901 11

There is a need for toxicity tests capable of recognizing indoor environments with compromised air quality, especially in the context of moisture damage. One of the key issues is sampling, which should both provide meaningful material for analyses and fulfill requirements imposed by practitioners using toxicity tests for health risk assessment. We aimed to evaluate different existing methods of sampling indoor particulate matter (PM) to develop a suitable sampling strategy for a toxicological as ...[more]

PMID: 27569522

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Project description:Background - Multiple health effects are associated with moisture damage in buildings. Studies explaining these associations and cell-level mechanisms behind the observed health effects are urgently called for. Objectives - Alongside general toxicological markers, we focused on characterizing gene expression in human airway epithelium after exposure to indoor air particulate matter (PM) sampled from houses with and without moisture damage. Methods - We performed detailed technical building inspections in 25 residential houses and categorized them based on the detection of moisture damages and the probability of occupant exposure. PM sampling was complemented by microbiological and volatile organic compound assessment. We exposed airway constructs to three doses (1:16, 1:8, 1:4) of PM from moisture-damaged (index) and non-moisture-damaged (reference) houses. The RNA of exposed constructs was sequenced targeting toxicology -related genes. We did groupwise comparisons between index and reference houses and pairwise comparisons in matched index/reference houses. We analyzed general toxicological markers and imaged the constructs with electron microscopy. Results - In pairwise comparison, several genes were differentially expressed. Genes related to multiple toxicological pathways were highlighted, while none of the genes was consistently expressed in all the comparisons. In groupwise comparison, CYP1A1 was statistically significantly over-expressed in index houses at all doses (dose 1:16 log2FC = 0.007, padj = 0.03; dose 1:8 log2FC = 0.077, padj = 0.018; dose 1:4 log2FC = 0.270, padj = 0.002) and NFKB1 at the highest dose 1:4 (log2FC = 0.124, padj = 0.029). General toxicological markers did not separate the index/reference houses. Discussion - The exposure to PM from index houses activates toxicology -related genes in airway constructs. While differential expression was not consistent among all the index/reference pairs, possibly due to compositional differences of bioactive particles, our study highlights CYP1A1 and NFKB1 as potential targets in moisture damage -associated cellular responses.

Project description:People generally spend more time indoors than outdoors resulting in a higher proportion of exposure to particulate matter (PM) occurring indoors. Consequently, indoor PM levels, in contrast to outdoor PM levels, may have a stronger relationship with lung function. To test this hypothesis, indoor and outdoor PM2.5 and fungal spore data were simultaneously collected from the homes of forty-four asthmatic children aged 10-16?years. An optical absorption technique was utilized on the collected PM2.5 mass to obtain concentrations of black carbon (BC) and ultraviolet light absorbing particulate matter, (UVPM; a marker of light absorbing PM2.5 emitted from smoldering organics). Enrolled children completed spirometry after environmental measurements were made. Given the high correlation between PM2.5, BC, and UVPM, principal component analysis was used to obtain uncorrelated summaries of the measured PM. Separate linear mixed-effect models were developed to estimate the association between principal components of the PM variables and spirometry values, as well as the uncorrelated original PM variables and spirometry values. A one-unit increase in the first principal component variable representing indoor PM (predominantly composed of UVPM and PM2.5) was associated with 4.1% decrease (99% CI?=?-6.9, -1.4) in FEV1/FVC ratio. 11.3??g/m3 increase in indoor UVPM was associated with 6.4% and 14.7% decrease (99% CI?=?-10.4, -2.4 and 99% CI?=?-26.3, -2.9, respectively) in percent predicted FEV1/FVC ratio and FEF25-75 respectively. Additionally, 17.7??g/m3 increase in indoor PM2.5 was associated with 6.1% and 12.9% decrease (99% CI?=?-10.2, -1.9 and 99% CI?=?-24.9, -1.0, respectively) in percent predicted FEV1/FVC ratio and FEF25-75, respectively. Outdoor PM, indoor BC, and indoor fungal spores were not significantly associated with lung function. The results indicate that indoor PM is more strongly associated with lung function in children with asthma as compared with outdoor PM.

Project description:ObjectivesMethicillin-resistant Staphylococcus aureus (MRSA) is an increasing public and occupational health concern. As transmission of MRSA can occur via contact with fomites, it is crucial to have sensitive methods for sampling of bacteria. The overall aim of this study was to obtain knowledge about methods and strategies for quantitative sampling Staphylococcus species on surfaces.MethodsThe study was designed as a comparative sampling experiment with different samplers [dipslide (two agar types), swabs (three brands, used wet and dry, and elution from swabs or plate diluted)] on smooth stainless steel surfaces spiked with MRSA and methicillin-sensitive S. aureus (MSSA). Furthermore, bacteria sampled from indoor surfaces with frequent or infrequent contact with hands were quantified and identified using matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry (MS).ResultsPre-moistened swabs in combination with dilution plating and dipslides were more sensitive than dry swabs. For recovery of MRSA and MSSA from surfaces with eSwabs, at least 0.3-100 CFU MRSA cm-2 and 5.3-8.6 CFU MSSA cm-2 should be present. The sensitivities of pre-moistened eSwabs were approximately 10-fold higher than those of dipslides and pre-moistened viscose and cotton swabs. The variation in concentrations of Staphylococcus species in replicate sampling of adjacent squares on indoor surfaces was higher for surfaces frequently touched by hands than for surfaces infrequently touched. In total 16 different Staphylococcus species were identified, and S. aureus was found only in 2 of 66 surface samples. A considerable overlap was found between species in replicate sampling within an environment and between the air and surfaces within an environment.ConclusionsPre-moistened eSwabs in combination with dilution plating were found to be the best method for surface sampling of MSSA and MRSA. The method can be used for assessing the risk of exposure and transmission of MRSA from environmental surfaces. To obtain a reliable measure of concentrations and the presence of Staphylococccus species a higher number of samples should be taken from surfaces with hand contact than from surfaces dominated by sedimented bacteria.

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Evaluation of sampling methods for toxicological testing of indoor air particulate matter.

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Evaluation of sampling methods for toxicological testing of indoor air particulate matter.

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