Persistence of viable MS2 and Phi6 bacteriophages on carpet and dust.

Resuspension of dust from flooring is a major source of human exposure to microbial contaminants, but the persistence of viruses on dust and carpet and the contribution to human exposure are often unknown. The goal of this work is to determine viability of MS2 and Phi6 bacteriophages on cut carpet, looped carpet, and house dust both over time and after cleaning. Bacteriophages were nebulized onto carpet or dust in artificial saliva. Viability was measured at 0, 1, 2, 3, 4, 24, and 48 h and after cleaning by vacuum, steam, hot water extraction, and disinfection. MS2 bacteriophages showed slower viability decay rates in dust (-0.11 hr-1 ), cut carpet (-0.20 hr-1 ), and looped carpet (-0.09 hr-1 ) compared to Phi6 (-3.36 hr-1 , -1.57 hr-1 , and -0.20 hr-1 , respectively). Viable viral concentrations were reduced to below the detection limit for steam and disinfection for both MS2 and Phi6 (p < 0.05), while vacuuming and hot water extraction showed no significant changes in concentration from uncleaned carpet (p > 0.05). These results demonstrate that MS2 and Phi6 bacteriophages can remain viable in carpet and dust for several hours to days, and cleaning with heat and disinfectants may be more effective than standard vacuuming.

Resuspension of particles deposited by nano-enabled consumer sprays: The role of product type, flooring material, and resuspension force.

With the development of nanotechnology, an increasing number of nano-enabled consumer products are introduced into the market. The release, deposition, and resuspension of particles from such products could be an important contributor to indoor air pollution and adverse health effects. Our study tested the spray and resuspension of seven nano-enabled consumer products and investigated how flooring material and resuspension force affected the resuspension of particles from these products. Results show that resuspension rates can range from 10-4 to 5 × 10-1  h-1 , depending on the product, flooring material (e.g., carpet and vinyl), and resuspension force (e.g., a walking adult and a moving child; the latter was simulated by a robotic sampler). The resuspension rate from the carpet was statistically significantly higher than that from vinyl flooring, while the resuspension rate by the adult was statiscally significantly higher than that by the robot. In addition, the interaction of investigated factors also played a role in particle resuspension rate. For a subgroup of products based on copper (Cu), silver (Ag), and zinc (Zn) nanomaterials, the resuspension rate reached as high 5 × 10-1  h-1 , rates higher than those reported in existing studies with house dust or Arizona Road Dust.

Effects of fully or partially slatted flooring designs on the performance, welfare and carcass characteristics of broiler chickens.

1. The objective of this study was to evaluate the effects of fully (FSF) or partially (PSF) flooring designs on animal-based welfare indicators in a fast-growing broiler genotype. Growth performance and carcass characteristics were assessed.2. One-d-old male chicks were randomly assigned to three groups: fully slatted flooring (100% slatted floor), partially slatted flooring (50% litter floor and 50% slatted floor) and conventional floor pens with litter (control, 100% deep litter) with 5 replicates of 14 male chicks. The litter was rice hull, as is usual in practice.3. Measurements of live body weight, feed intake, feed conversion ratio, mortality and performance index were collected before depopulation at 42 d old. Welfare assessments were done by individual ante- and post-mortem carcass inspection during depopulation and after slaughter.4. Broiler live body weight (P < 0.03) and feed intake (P < 0.003) and ante-mortem welfare indicators (P < 0.001) were positively affected by FSF and PSF compared to the conventional deep litter system. Post-mortem lesion scores on wings and shoulder were similar in all floor types but there were significant differences for the lesions on breast (P < 0.003) and pygostyle (P < 0.05).5. In conclusion, FSF and PSF resulted in higher body weights, while reducing incidence of foot pad and hock joint deformations in live animals.

Quantifying the uncertainty in tribometer measurements on walkway surfaces.

Properly estimating and reporting the uncertainty of walkway surface friction is key to ensuring pedestrian safety. Here we quantified the amount and sources of uncertainty in friction measurements by having four users of four units of each of two walkway tribometer models (Slip-Test Mark IIIB, English XL) perform 12 measurements on four samples of four different surfaces that ranged from slippery to slip-resistant. We found that 51-82% of the total variance in the measurements was explained by the user, unit, sample and a user-unit interaction, which means that the variance a single user calculates from their own data does not capture most of the uncertainty in their measurements. Based on these data, the minimum uncertainty associated with the mean of a user's measurements is ±0.064 (Mark IIIB) and ±0.072 (XL) to be 95% confident that their mean captures a surface's available friction. Practitioner Summary: Walkway surface friction measurements are less accurate than they appear. Based on an experiment quantifying the amount and sources of uncertainty in surface friction measurements using two common tribometers, we quantified and report the minimum uncertainty that users can assign to their walkway surface friction measurements. Abbreviations: ANOVA: analysis of variance; ANSI: American National Standards Institute; CI: confidence interval; E: east; ILS: interlaboratory study; ISO: International Standards Organization; JCGM: joint committee for guides in metrology; N: north; S: south; SBR: styrene-butadiene rubber; SD: standard deviation; TR: test result; W: west.

Effect of rubber and concrete flooring on resting behavior, hock injuries, and milk production of primiparous Friesian crossbred dairy cows housed in a free-stall barn in Mid-Country, Sri Lanka.

The floor surface of the cubicle is a detrimental factor on cow comfort. The effects of two floor types, rubber and concrete, on dairy cow comfort and milk production were compared for a period of 13 weeks. Fourteen Friesian crossbred dairy cows with an average body weight of 425.67 ± 61.12 kg (mean ± SD), nose to tail body length of 2.07 ± 0.15 m, rump height of 1.29 ± 0.02 m, hook bone width of 0.48 ± 0.05 m, and body condition score (BCS) of 4.13 ± 0.44 were used, with seven cows per flooring treatment. The cows produced a mean of 15.93 ± 4.03 l/cow/day and a constant feeding plan was practiced. The swelling and wound severity of hocks diminished (P < 0.05) starting at the third and tenth weeks, respectively. Daily lying time/h (concrete: 9.67 ± 1.24, rubber: 10.60 ± 0.69, P = 0.046) and average duration of lying bouts/min increased (concrete: 58.16 ± 7.74, rubber: 65.66 ± 9.85, P = 0.050) starting from the twelfth week on rubber bedding. Prevalence of mastitis, lameness, and cow cleanliness remained unchanged on floor treatments. A progressive increase in daily milk production/l (concrete: 13.37 ± 1.46, rubber: 16.67 ± 2.24, P = 0.007) of cows in rubber bedding was observed at the fourth week of the experiment. Hence, the current study suggests that the use of softer bedding such as rubber mats could improve cow comfort and daily milk production of cows.

Safety considerations for forward falls.

OBJECTIVE: Forward falls are among the most frequent causes of upper extremity fractures. This study investigated the safety considerations to prevent wrist injuries during bimanual forward falls. METHODS: A biomechanical model was developed with two separated arms to facilitate investigation of asymmetrical contact and predict the impact force applied to each hand separately. To validate the developed model, a series of fall experiments were conducted in which one hand collided with a hard surface, while the other collided with a soft surface. RESULTS: The results show that the impact force applied to each hand is independent of the other. Using these results and our model, the safety aspects of human forward falls were analyzed with a view to preventing injuries. Specifically, we sought to determine the safe range of surface stiffness and damping to ensure that the occurrence of forward falls does not lead to trauma. CONCLUSION: The results of this study can be applied in the design of compliant flooring to ensure the safety of people in environments with potential fall hazards. From a robotics viewpoint, the results are applicable in the design of compliant flooring for shared workplaces, where robots collaborate with people and collisions between humans and robots may cause falls.

Systematic review of modifiable risk factors shows little evidential support for most current practices in Cryptosporidium management in bovine calves.

Cryptosporidiosis is common in young calves, causing diarrhoea, delayed growth, poor condition and excess mortality. No vaccine or cure exists, although symptomatic onset may be delayed with some chemoprophylactics. Other response and management strategies have focused on nutritional status, cleanliness and biosecurity. We undertook a systematic review of observational studies to identify risk or protective factors that could prevent Cryptosporidium parvum infection in calves. Included studies used multivariate analysis within cohort, cross-sectional or case-control designs, of risk factors among young calves, assessing C. parvum specifically. We tabulated data on characteristics and study quality and present narrative synthesis. Fourteen eligible studies were found; three of which were higher quality. The most consistent evidence suggested that risk of C. parvum infection increased when calves had more contact with other calves, were in larger herds or in organic production. Hard flooring reduced risk of infection and calves tended to have more cryptosporidiosis during warm and wet weather. While many other factors were not found to be associated with C. parvum infection, analyses were usually badly underpowered, due to clustering of management factors. Trials are needed to assess effects of manipulating calf contact, herd size, organic methods, hard flooring and temperature. Other factors need to be assessed in larger observational studies with improved disaggregation of potential risk factors.

Morphology and quantification of fungal growth in residential dust and carpets.

Mold growth indoors is associated with negative human health effects, and this growth is limited by moisture availability. Dust deposited in carpet is an important source of human exposure due to potential elevated resuspension compared to hard floors. However, we need an improved understanding of fungal growth in dust and carpet to better estimate human exposure. The goal of this study was to compare fungal growth quantity and morphology in residential carpet under different environmental conditions, including equilibrium relative humidity (ERH) (50%, 85%, 90%, 95%, 100%), carpet fiber material (nylon, olefin, wool) and presence/absence of dust. We analyzed incubated carpet and dust samples from three Ohio homes for total fungal DNA, fungal allergen Alt a 1, and fungal morphology. Dust presence and elevated ERH (≥85%) were the most important variables that increased fungal growth. Elevated ERH increased mean fungal DNA concentration (P < 0.0001), for instance by approximately 1000 times at 100% compared to 50% ERH after two weeks. Microscopy also revealed more fungal growth at higher ERH. Fungal concentrations were up to 100 times higher in samples containing house dust compared to no dust. For fiber type, olefin had the least total fungal growth, and nylon had the most total fungi and A. alternata growth in unaltered dust. Increased ERH conditions were associated with increased Alt a 1 allergen concentration. The results of this study demonstrate that ERH, presence/absence of house dust, and carpet fiber type influence fungal growth and allergen production in residential carpet, which has implications for human exposure.

Influencing factors on the foot health of captive Asian elephants (Elephas maximus) in European zoos.

Pathological lesions of feet occur frequently in captive elephant populations. To improve foot health, it is important to identify risk factors associated with such pathologies. Several previous studies have analyzed potentially influencing factors but were limited, for example, by small sample sizes. This study analyzed the relationship between 87 independent variables and the foot health score of 204 Asian elephants (Elephas maximus) in European zoos using bivariate correlation, multivariable regression models, and principal component analysis (PCA). Correlation and regression tests revealed significant results for 30 different variables, mainly with small effect sizes. Only three variables were significant in more than one test: sex, time spent indoors, and time spent on hard ground, with lower scores (i.e. less or less severe pathological lesions) in females, and when less time is spent indoors or on hard ground. Due to small effect sizes and differing results of the statistical tests, it is difficult to determine which risk factors are most important. Instead, a holistic consideration appears more appropriate. A biplot of the PCA shows that factors representing more advanced husbandry conditions (e.g. large areas, high proportions of sand flooring) were associated with each other and with decreased foot scores, whereas indicators of more limited conditions (e.g. high proportions of hard ground, much time spent indoors) were also associated with each other but increased the foot score. In conclusion, instead of resulting from just one or two factors, reduced foot health might be an indicator of a generally poorer husbandry system.

Soft and persistent-The influence of sand-flooring and calves on the resting behavior of a zoo-kept African elephant (Loxodonta africana) group.

Caring for all aspects of zoo elephants' well-being is considered a major challenge. Providing an appropriate flooring substrate to facilitate lying rest presents a meaningful part of a holistic management concept. Investigating the impact of a new sand flooring on the nocturnal resting behavior of a breeding group of seven African elephants living at one zoo revealed more total lying rest, longer bouts of lying rest and a reduced side preference in the adult females. With an average total daily lying rest of about 1.5-2.0 hrs, the investigated zoo elephants expressed longer lying rest compared to recently reported data from free-ranging individuals in Botswana. In addition, the presence of nursing calves in the observed elephant group seemed to impact the resting pattern of all group members, with around 60% of all lying bouts being discontinued after interruption by the youngsters. With respect to observed nursing during leaning rest, we encourage the installation of appropriate horizontal structures in breeding facilities to support leaning rest behavior of their female elephants. In doing so, zoos may improve rest quality of nursing females, and, in general, the welfare aspect of sleep for their elephants.

Emissions of DEHP-free PVC flooring.

Degrading 2-ethylhexyl-containing PVC floorings (eg DEHP-PVC floorings) and adhesives emit 2-ethylhexanol (2-EH) in the indoor air. The danger of flooring degradation comes from exposing occupants to harmful phthalates plasticisers (eg DEHP), but not from 2-EH as such. Since the EU banned the use of phthalates in sensitive applications, the market is shifting to use DEHP-free and alternative types of plasticisers in PVC products. However, data on emissions from DEHP-free PVC floorings are scarce. This study aimed at assessing the surface and bulk emissions of two DEHP-free PVC floorings over three years. The floorings were glued on the screed layer of concrete casts at 75%, 85%, and 95% RH. The volatile organic compounds (VOCs) were actively sampled using FLEC (surface emissions) and micro-chamber/thermal extractor (µ-CTE, bulk emissions) onto Tenax TA adsorbents and analyzed with TD-GC-MS. 2-EH, C9-alcohols, and total volatile organic compound (TVOC) emissions are reported. Emissions at 75% and 85% RH were similar. As expected, the highest emissions occurred at 95% RH. 2-EH emissions originated from the adhesive. Because the two DEHP-free floorings tested emitted C9-alcohols at all tested RH, it makes the detection of flooring degradation harder, particularly if the adhesive used does not emit 2-EH.

Impact on lung function among children exposed to home new surface materials: The seven Northeastern Cities Study in China.

We conducted a cross-sectional study to investigate the associations between recent home renovation exposure and lung function in children. We randomly recruited 7326 school children residing in 24 districts from seven cities in northeastern China. We collected information about home renovations from parents using a questionnaire and lung function measurements from children using spirometer recordings gathered by trained professionals and expressed as the forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), maximal mid-expiratory flow (MMEF), and peak expiratory flow (PEF). We identified higher odds of diminished lung function among these with home renovation in the previous 2 years compared to those without home renovation in the previous 2 years, for FVC (odds ratios [ORs] = 1.84 [95%CI: 1.58, 2.15]; FEV1: ORs = 2.82 [95%CI: 2.36, 3.36]; PEF: ORs = 1.51 [95%CI: 1.24, 1.83]; and MMEF: ORs = 1.90 [95%CI: 1.60, 2.24]). The associations were stronger among children exposed to new polyvinyl chloride (PVC) flooring compared to children exposed to other surface materials. Our results were consistent throughout the analysis of each type of renovation materials. In conclusion, recent home renovation exposure was associated with poor lung function among children. Strategies to protect home owners and their families from respiratory hazards during and after renovation are required.

PVC flooring at home and uptake of phthalates in pregnant women.

Phthalates are used as plasticizers in polyvinyl chloride (PVC) materials and it is known that phthalates may migrate into the surrounding environment and then become a source for human uptake. The aim of the study was to investigate whether residential PVC flooring was related to the urinary levels of phthalate metabolites determined in pregnant women. The data were from the Swedish SELMA study where sampling was conducted during the time period 2007-2010. Spot urine samples from 1674 women at the end of the first trimester were analyzed for 14 metabolites from seven phthalates and one phthalate alternative. Data on flooring material in the kitchen and the parents' bedrooms as well as potential confounders were collected by postal questionnaires at the same time as the urine samples were taken. Multiple regression modeling by least square geometric mean and weighted quantile sum regression was applied to log-transformed and creatinine-adjusted phthalate metabolite concentrations adjusted for potential confounders from questionnaire data. This study has found significantly higher urinary levels of the BBzP metabolite (MBzP) in pregnant women living in homes with PVC flooring as compared to homes with other flooring materials.

Kinetic effect of different ground conditions on the sole of the claws of standing and walking dairy cows.

For the first time, we analyzed the direct kinetic effects of concrete and rubber flooring on the soles of live dairy cows' claws while standing and walking. Ten adult dairy cows were equipped with foil-based pressure sensors (HoofSystem, Tekscan Inc., Boston, MA) under their left hind leg using a leather claw shoe. These sensors captured parameters of pressure distribution and vertical ground reaction forces while the cows walked on the 2 tested flooring types. The mean pressure was 15.1 to 21.1% lower on rubber flooring compared with concrete; mean pressure values (± standard deviation) were 36.32 ± 7.77 N/cm2 for static measures and 57.33 ± 11.77 N/cm2 for dynamic measures. We observed an even more obvious relief on rubber flooring in the maximum pressure loads, which were 30.1 to 32.7% lower on rubber flooring compared with concrete; mean pressure values (± standard deviation) were 98.79 ± 14.49 N/cm2 for static measures and 150.45 ± 20.87 N/cm2 for dynamic measures). The force-time curves of the dynamic measures essentially showed biphasic curve progression, with local peaks at 29 and 79% of the stance phase. However, we found considerable differences in curve progression between individuals and between the lateral and medial claws, which may be verified in further investigations with more animals. The study showed a noticeable reduction in mechanical load during standing and walking on rubber flooring compared with concrete.

Ten questions concerning the implications of carpet on indoor chemistry and microbiology.

Carpet and rugs currently represent about half of the United States flooring market and offer many benefits as a flooring type. How carpets influence our exposure to both microorganisms and chemicals in indoor environments has important health implications but is not well understood. The goal of this manuscript is to consolidate what is known about how carpet impacts indoor chemistry and microbiology, as well as to identify the important research gaps that remain. After describing the current use of carpet indoors, questions focus on five specific areas: 1) indoor chemistry, 2) indoor microbiology, 3) resuspension and exposure, 4) current practices and future needs, and 5) sustainability. Overall, it is clear that carpet can influence our exposures to particles and volatile compounds in the indoor environment by acting as a direct source, as a reservoir of environmental contaminants, and as a surface supporting chemical and biological transformations. However, the health implications of these processes are not well known, nor how cleaning practices could be optimized to minimize potential negative impacts. Current standards and recommendations focus largely on carpets as a primary source of chemicals and on limiting moisture that would support microbial growth. Future research should consider enhancing knowledge related to the impact of carpet in the indoor environment and how we might improve the design and maintenance of this common material to reduce our exposure to harmful contaminants while retaining the benefits to consumers.

Stepping behavior and muscle activity of dairy cattle standing on concrete or rubber flooring for 1 or 3 hours.

The type of flooring in dairy cattle systems influences cows' health and welfare. Although concrete is common, the use of more compressible flooring, such as rubber, is increasing. Cows prefer to stand and walk on rubber surfaces than on concrete; however, it is largely unknown how walking and standing for longer periods of time influence muscle activity and fatigue. Therefore, we used measures of behavior and muscle activity to investigate the potential benefits of providing a rubber flooring surface to dairy cattle. Sixteen lactating Holstein cows were forced to stand on either concrete or rubber flooring for 1 or 3 h in a 2 × 2 crossover design. Surface electromyograms (SEMG) and skin surface temperature were used to evaluate muscle activity, fatigue, and movement of muscle activity between the hind legs. Activity of 2 muscles, the bicep femoris and middle gluteal, was assessed during both static contractions, when cows transferred weight to each hind leg, before and after 1 and 3 h of standing, and dynamic contractions, associated with steps and with shifts in weight without steps. In addition, we evaluated stepping rate, time between each step, feeding behavior, skin surface temperature, and latency to lie down after standing. Standing duration influenced both the behavior and muscle activity of cows. Stepping rate increased with standing time for cows on both flooring types. Static muscle activity parameters of the bicep femoris muscle were higher after 3 h of standing for cows standing on both flooring types (2.3 and 3.6% increases in median amplitude and median power frequency, respectively) compared with the change after 1 h and compared with baseline values before the standing treatment. Flooring type influenced the behavior and muscle activity of the cows, particularly during the first hour of exposure; cows standing on rubber had a higher stepping rate, shorter interval between steps, and higher number of SEMG shifts (muscle activity shifts with or without visible steps) than cows on concrete. There was no difference in skin surface temperature, feeding behavior, or latency to lie down between the treatments. The results show that standing on a rubber flooring caused a different initial behavioral response compared with standing on concrete; however, possible reasons for these changes are unclear. Standing for 3 h resulted in an increase in stepping rate and in some muscle activity parameters; however, the results regarding muscle fatigue in relation to flooring type are inconclusive.

Potential Exposure and Cancer Risk from Formaldehyde Emissions from Installed Chinese Manufactured Laminate Flooring.

Lumber Liquidators (LL) Chinese-manufactured laminate flooring (CLF) has been installed in >400,000 U.S. homes over the last decade. To characterize potential associated formaldehyde exposures and cancer risks, chamber emissions data were collected from 399 new LL CLF, and from LL CLF installed in 899 homes in which measured aggregate indoor formaldehyde concentrations exceeded 100 µg/m3 from a total of 17,867 homes screened. Data from both sources were combined to characterize LL CLF flooring-associated formaldehyde emissions from new boards and installed boards. New flooring had an average (±SD) emission rate of 61.3 ± 52.1 µg/m2 -hour; >one-year installed boards had ∼threefold lower emission rates. Estimated emission rates for the 899 homes and corresponding data from questionnaires were used as inputs to a single-compartment, steady-state mass-balance model to estimate corresponding residence-specific TWA formaldehyde concentrations and potential resident exposures. Only ∼0.7% of those homes had estimated acute formaldehyde concentrations >100 µg/m3 immediately after LL CLF installation. The TWA daily formaldehyde inhalation exposure within the 899 homes was estimated to be 17 µg/day using California Proposition 65 default methods to extrapolate cancer risk (below the regulation "no significant risk level" of 40 µg/day). Using a U.S. Environmental Protection Agency linear cancer risk model, 50th and 95th percentile values of expected lifetime cancer risk for residents of these homes were estimated to be 0.33 and 1.2 per 100,000 exposed, respectively. Based on more recent data and verified nonlinear cancer risk assessment models, LL CLF formaldehyde emissions pose virtually no cancer risk to affected consumers.

Gait of dairy cows on floors with different slipperiness.

This study assessed the slip resistance of different types of solid flooring in cattle housing using a range of technical tests and gait analysis. Dynamic and static coefficient of friction, skid resistance, and abrasiveness were tested on concrete flooring with a smooth finish, a grooved pattern, or a tamped pattern, acid-resistant mastic asphalt, soft rubber mats, and a worn slatted concrete floor. Coefficients of friction and skid resistance were tested under clean and slurry-soiled conditions. Linear kinematic variables were assessed in 40 cows with trackway measurements after the cows passed over the floors in a straight walk. All gait variables were assessed as deviations from those obtained on the slatted concrete floor, which was used as a baseline. The coefficient of friction tests divided the floors into 3 categories: concrete flooring, which had a low coefficient of friction (0.29-0.41); mastic asphalt flooring, which had medium values (0.38-0.45); and rubber mats, which had high values (0.49-0.57). The highest abrasion (g/10 m) was on the asphalt flooring (4.48), and the concrete flooring with a tamped pattern had significantly higher abrasiveness (2.77) than the other concrete floors (1.26-1.60). Lowest values on the skid-resistance tests (dry/wet) were for smooth concrete (79/35) and mastic asphalt (65/47), especially with a slurry layer on the surface. Gait analysis mainly differentiated floors with higher friction and abrasion by longer strides and better tracking. Step asymmetry was lower on floors with high skid-resistance values. The most secure cow gait, in almost every aspect, was observed on soft rubber mats. Relationships between gait variables and physical floor characteristics ranged from average to weak (partial correlations 0.54-0.16). Thus, none of the physical characteristics alone was informative enough to characterize slip resistance. With reference to gait analysis, the abrasiveness of the hard surfaces was more informative than the coefficient of friction, but the effect of pattern was better detected by skid-resistance measurements. Consequently, several physical characteristics are needed to objectively describe the slip resistance of cattle floors. Soft rubber mats gave better tracking than hard, solid floors, even with a grooved surface or a tamped pattern.

Chamber bioaerosol study: human emissions of size-resolved fluorescent biological aerosol particles.

Humans are a prominent source of airborne biological particles in occupied indoor spaces, but few studies have quantified human bioaerosol emissions. The chamber investigation reported here employs a fluorescence-based technique to evaluate bioaerosols with high temporal and particle size resolution. In a 75-m(3) chamber, occupant emission rates of coarse (2.5-10 µm) fluorescent biological aerosol particles (FBAPs) under seated, simulated office-work conditions averaged 0.9 ± 0.3 million particles per person-h. Walking was associated with a 5-6× increase in the emission rate. During both walking and sitting, 60-70% or more of emissions originated from the floor. The increase in emissions during walking (vs. while sitting) was mainly attributable to release of particles from the floor; the associated increased vigor of upper body movements also contributed. Clothing, or its frictional interaction with human skin, was demonstrated to be a source of coarse particles, and especially of the highly fluorescent fraction. Emission rates of FBAPs previously reported for lecture classes were well bounded by the experimental results obtained in this chamber study. In both settings, the size distribution of occupant FBAP emissions had a dominant mode in the 3-5 µm diameter range.

An assessment of formaldehyde emissions from laminate flooring manufactured in China.

Formaldehyde emissions from two laminate flooring products, labeled as California Air Resources Board (CARB) compliant, were evaluated. Passive 24-hr samples (n = 79) and real-time measurements were collected following installation and removal of the products in two rooms of similar size. Mean formaldehyde concentrations following installation were 0.038 and 0.022 ppm for Products 1 and 2 respectively, and 7 days after flooring removal the concentrations returned to background pre-installation levels. Both products were also evaluated in a small chamber (ASTM D6007) using Deconstructive (de-laminated product) and Non-Deconstructive (intact product) methods. Deconstructive testing showed that Product 1 exceeded the applicable CARB emission standard by 4-fold, while Product 2 was equivalent to the standard. Non-Deconstructive measurements were far below the Deconstructive results and were used to predict 24-hr steady-state room air concentrations. Based on the products that we tested (one of which was found to not be compliant with the CARB standard), the airborne formaldehyde concentrations measured following installation in a real-world setting would not be expected to elicit adverse acute health effects.