Formaldehyde Vapor Characteristics in Varied Decontamination Environments.

INTRODUCTION: This effort investigated formaldehyde vapor characteristics under various environmental conditions by the analyses of air samples collected over a time-course. This knowledge will help responders achieve desired formaldehyde exposure parameters for decontamination of affected spaces after a biological contamination incident. METHODS: Prescribed masses of paraformaldehyde and formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor. Adsorbent cartridges were used to collect air samples from the test chamber at predetermined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. In addition, material demand for the formaldehyde was evaluated by inclusion of arrays of Plexiglas panels in the test chamber to determine the impact of varied surface areas within the test chamber. Temperature was controlled with a circulating water bath connected to a radiator and fan inside the chamber. Relative humidity was controlled with humidity fixed-point salt solutions and water vapor generated from evaporated water. RESULTS: Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations in the ambient temperature trials (approximately 22°C). The addition of clear Plexiglas panels to increase the surface area of the test chamber interior resulted in appreciable decreases of formaldehyde air concentration when compared to an empty test chamber. CONCLUSION: This work has shown that environmental variables and surface-to-volume ratios in the decontaminated space may affect the availability of formaldehyde in the air and, therefore, may affect decontamination effectiveness.

Decontamination of Bacillus Spores with Formaldehyde Vapor under Varied Environmental Conditions.

Introduction: This study investigated formaldehyde decontamination efficacy against dried Bacillus spores on porous and non-porous test surfaces, under various environmental conditions. This knowledge will help responders determine effective formaldehyde exposure parameters to decontaminate affected spaces following a biological agent release. Methods: Prescribed masses of paraformaldehyde or formalin were sublimated or evaporated, respectively, to generate formaldehyde vapor within a bench-scale test chamber. Adsorbent cartridges were used to measure formaldehyde vapor concentrations in the chamber at pre-determined times. A validated method was used to extract the cartridges and analyze for formaldehyde via liquid chromatography. Spores of Bacillus globigii, Bacillus thuringiensis, and Bacillus anthracis were inoculated and dried onto porous bare pine wood and non-porous painted concrete material coupons. A series of tests was conducted where temperature, relative humidity, and formaldehyde concentration were varied, to determine treatment efficacy outside of conditions where this decontaminant is well-characterized (laboratory temperature and humidity and 12 mg/L theoretical formaldehyde vapor concentration) to predict decontamination efficacy in applications that may arise following a biological incident. Results: Low temperature trials (approximately 10°C) resulted in decreased formaldehyde air concentrations throughout the 48-hour time-course when compared with formaldehyde concentrations collected in the ambient temperature trials (approximately 22°C). Generally, decontamination efficacy on wood was lower for all three spore types compared with painted concrete. Also, higher recoveries resulted from painted concrete compared to wood, consistent with historical data on these materials. The highest decontamination efficacies were observed on the spores subjected to the longest exposures (48 hours) on both materials, with efficacies that gradually decreased with shorter exposures. Adsorption or absorption of the formaldehyde vapor may have been a factor, especially during the low temperature trials, resulting in less available formaldehyde in the air when measured. Conclusion: Environmental conditions affect formaldehyde concentrations in the air and thereby affect decontamination efficacy. Efficacy is also impacted by the material with which the contaminants are in contact.

Passive indoor air sampling for consumer product chemicals: a field evaluation study.

Innovative exposure measurement methods are needed for large environmental health studies, particularly for semivolatile organic compounds (SVOCs). Active air sampling methods are costly to implement, but passive air sampling presents a viable method. To expand and improve the use of passive air samplers (PAS) for indoor SVOC monitoring, we designed a unique, compact sampler using commercially available polyurethane foam (PUF) disks housed within durable, easy-to-setup, low-profile enclosures. We evaluated the new design using co-located active air samplers (AAS) and analyzed for SVOCs. Most of the targeted SVOCs found using active sampling (27 of 33) were also detected using passive sampling. We found good agreement (R2 = 0.88) between active and passive sampling methods for characterizing the relative abundance of each chemical, and the measured active sampler concentrations and passive sampler masses were significantly positively correlated for 14 of 21 chemicals, for which correlations could be estimated. We found that measurements of many SVOCs originating from consumer products and typically found in the gas-phase (log KOA < 10) can be reliably ranked-and thus appropriate for epidemiological studies-using this PAS design. These SVOCs include diethyl phthalate, AHTN, HHCB, tris(2-chloroethyl) phosphate, dibutyl phthalate, and tris(1-chloro-2-propyl) phosphate, as well as methyl paraben, benzophenone, and benzophenone-3, which have not previously been measured by passive sampling. This PAS can be used in epidemiological studies involving consumer product chemicals and complements other novel exposure tools.

Chemical exposures in recently renovated low-income housing: Influence of building materials and occupant activities.

Health disparities in low-income communities may be linked to residential exposures to chemicals infiltrating from the outdoors and characteristics of and sources in the home. Indoor sources comprise those introduced by the occupant as well as releases from building materials. To examine the impact of renovation on indoor pollutants levels and to classify chemicals by predominant indoor sources, we collected indoor air and surface wipes from newly renovated "green" low-income housing units in Boston before and after occupancy. We targeted nearly 100 semivolatile organic compounds (SVOCs) and volatile organic compounds (VOCs), including phthalates, flame retardants, fragrance chemicals, pesticides, antimicrobials, petroleum chemicals, chlorinated solvents, and formaldehyde, as well as particulate matter. All homes had indoor air concentrations that exceeded available risk-based screening levels for at least one chemical. We categorized chemicals as primarily influenced by the occupant or as having building-related sources. While building-related chemicals observed in this study may be specific to the particular housing development, occupant-related findings might be generalizable to similar communities. Among 58 detected chemicals, we distinguished 25 as primarily occupant-related, including fragrance chemicals 6-acetyl-1,1,2,4,4,7-hexamethyltetralin (AHTN) and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta[g]-2-benzopyran (HHCB). The pre- to post-occupancy patterns of the remaining chemicals suggested important contributions from building materials for some, including dibutyl phthalate and xylene, whereas others, such as diethyl phthalate and formaldehyde, appeared to have both building and occupant sources. Chemical classification by source informs multi-level exposure reduction strategies in low-income housing.