Marta Hernandez

Acute exposure to elevated PM2.5 generated by traffic and cardiopulmonary health effects in healthy older adults

There are evidences for exposure to vehicular emissions and adverse cardiopulmonary health effects. This study attempted to further explore these effects on elderly. This study monitored personal PM2.5 concentrations and ambulatory electrocardiograms continuously for 24 h on 1 working day in 3 separate weeks for 11 school crossing guards. Spirometry was also performed before and after the morning shift. The traffic at each work location was video recorded during one of the three morning shifts. The increases in the average personal PM2.5 concentrations (baseline PM2.5 was subtracted) of 1.2–87 and 1.1–98 μg/m3 were observed during the 1-h morning (ΔPM2.5-ave-m) and afternoon shift (ΔPM2.5-ave-a), respectively. Traffic count was not a significant predictor of the ΔPM2.5-ave-m (P=0.78). Mean heart rate variability (HRV), measured as 5-min standard deviation of normal-to-normal (SDNN) beats during the 10-min rest periods, decreased 18–26% (P<0.02) 15 min, 2 and 4 h after the morning shift, but changes in SDNN (ΔSDNN) were insignificant post-afternoon exposure (−0.3 to −7% with P>0.53). ΔSDNN were negatively associated with ΔPM2.5-ave-m, with the strongest association at 2 h after the morning shift (P<0.01) but insignificant 4 h after the morning exposure. The peak PM2.5 concentration (ΔPM2.5-peak, baseline PM2.5 was subtracted) was not a significant predictor for ΔSDNN, and no clear effect of PM2.5 exposure on heart rate was observed. There was no effect of PM exposure on lung function (P>0.16), either. In conclusion, acute exposure to the PM2.5 resulting from mobile sources can cause acute decline in HRV in healthy older adults, suggesting one of the biological mechanisms for the adverse cardiovascular health effects associated with traffic-related air pollution. Traffic count may not be an appropriate surrogate measure of acute personal exposure to vehicular emission in traffic congested areas.

Use of a robotic sampling platform to assess young children's exposure to indoor bioaerosols

UNLABELLED Indoor exposures to allergens, mold spores, and endotoxin have been suggested as etiological agents of asthma; therefore, accurate determination of those exposures, especially in young children (6-36 months), is important for understanding the development of asthma. Because use of personal sampling equipment in this population is difficult, and in children <1 year of age impossible, we developed a personal sampling surrogate: the Pretoddler Inhalable Particulate Environmental Robotic (PIPER) sampler to better estimate their exposures. During sampling, PIPER simulates the activity patterns, speed of motion, and the height of the breathing zones of young children, and mechanically resuspends the deposited dust just as a young child does during running and crawling. The concentrations of allergens, mold spores, and endotoxin measured by PIPER were compared to those measured using traditional stationary air sampling method in 75 homes in central New Jersey, United States. Endotoxin was detected in all homes with median concentrations of 1.0 and 0.55 EU/m(3) for PIPER and stationary sampler, respectively. The difference in median concentrations obtained using the two methods was statistically significant for homes with carpeted floors (P = 0.0001) in the heating season. For such homes, the average ratio of endotoxin concentration measured by PIPER to the stationary sampler was 2.96 (95% CI 2.29-3.63). Fungal spores were detected in all homes, with median fungal concentrations of 316 and 380 spores/m(3) for PIPER and stationary sampler, respectively. For fungi, the difference between the two sampling methods was not statistically significant. For both sampling methods, the total airborne mold levels were statistically significantly higher in the non-heating season than in the heating season. Allergens were detected in ~15% of investigated homes. The data indicate that the traditional stationary air-sampling methods may substantially underestimate personal exposures to endotoxin, especially due to resuspension of dust from carpeted floor surfaces. A personal sampling surrogate, such as PIPER, is a feasible approach to estimate personal exposures in young children. PIPER should be seriously considered as the sampling platform for future exposure studies in young children. PRACTICAL IMPLICATIONS This study investigated potential indoor bioaerosol exposure of young children using a Pretoddler Inhalable Particulate Environmental Robotic (PIPER) sampler platform. The results show that the traditional stationary air-sampling methods can substantially underestimate personal exposures to resuspended material, and that a personal sampling surrogate, such as PIPER, offers a feasible surrogate for measuring personal inhalation exposures of young children.

Development and in-home testing of the Pretoddler Inhalable Particulate Environmental Robotic (PIPER Mk IV) sampler.

Exposure and dose estimation are essential to understanding the etiology of environmentally linked childhood diseases. The behavior of resuspended particulate matter (PM) suggests that stationary measurements may underestimate household exposures in young children (ages 6-36 months). Because of the size and weight of the sampling equipment, use of personal samplers in this age group is either difficult or impossible. The Pretoddler Inhalable Particulate Environmental Robotic (PIPER Mk IV) sampler has been developed to provide a surrogate method to ascertain personal exposures to PM for this age group. As part of a study of childhood asthma, 55 homes in central New Jersey were tested. Simultaneous sampling for inhalable PM using stationary (110 cm height) and PIPER mobile sampler were carried out. In homes with bare floors (N=21), the absolute difference was 3.9 μg/m3 (SE=3.01; p=0.217) and relative difference (PIPER/Stationary) was 1.12 (linearized SE=0.11). On carpets (N=34), the absolute difference was 54.1 μg/m3 (SE=13.50; p=0.0003), and the relative difference was 2.30 (linearized SE=0.34). The results confirm the importance of understanding the personal dust cloud caused by childrens activity in a room, particularly when rugs or carpets are present.

Improved exposure characterization with robotic (PIPER) sampling and association with children’s respiratory symptoms, asthma and eczema

Particulate matter (PM) and its constituents are recognized risk factors for the development of respiratory symptoms and illness in children. Most measurements of exposure have relied upon stationary indoor monitors (SIMs), overlooking the role of resuspended PM. To improve exposure characterization to resuspended aerosol PM, a recently developed methodology has been employed. The goal of this study was to characterize the resuspendable fraction of house dust and early childhood exposures to PM and its constituents in the child’s home and compare conventional SIM and the Pre-toddler Inhalable Particulate Environmental Robotic (PIPER), an innovative mobile sampler. The study seeks to demonstrate that PIPER provides a more relevant estimate of exposure from inhalable particulate matter through improved correlation with respiratory symptoms in young children. Seventy-five households with children between 3 and 59 months of age were recruited from clinics in central New Jersey. Demographic information, and responses to a health questionnaire based upon that used by the International Study of Allergies and Asthma in Childhood (ISAAC), and household data were collected. Household exposures to inhalable PM (PM100) and endotoxin were determined with simultaneous SIM and mobile (PIPER) sampling. Univariate and multivariate analyses were carried out. History of wheeze (“recent” (<1 year) and “ever”), cough, asthma and eczema was evaluated. Multivariate analysis models included PM100 and endotoxin levels by tertiles of exposure. Risk of asthma for the highest tertile of PM100, as measured by PIPER (odds ratio=4.2; 95% confidence interval 0.7–24.0), was compared with measurements by SIM (odds ratio=0.7; 95% confidence interval 0.2–2.6). Measurements of PM and its constituents with PIPER are more strongly associated with asthma, eczema and wheeze compared with measurements using SIMs. Application of this methodology may provide useful insights into early childhood exposures related to the etiology of childhood illnesses associated with inhalation exposures.

Comparison of particulate matter exposure estimates in young children from personal sampling equipment and a robotic sampler.

Accurate characterization of particulate matter (PM) exposure in young children is difficult, because personal samplers are often too heavy, bulky or impractical to be used. The Pretoddler Inhalable Particulate Environmental Robotic (PIPER) sampler was developed to help address this problem. In this study, we measured inhalable PM exposures in 2-year-olds via a lightweight personal sampler worn in a small backpack and evaluated the use of a robotic sampler with an identical sampling train for estimating PM exposure in this age group. PM mass concentrations measured by the personal sampler ranged from 100 to almost 1,200 μg/m3, with a median value of 331 μg/m3. PM concentrations measured by PIPER were considerably lower, ranging from 14 to 513 μg/m3 with a median value of 56 μg/m3. Floor cleaning habits and activity patterns of the 2-year-olds varied widely by home; vigorous play and recent floor cleaning were most associated with higher personal exposure. Our findings highlight the need for additional characterization of children’s activity patterns and their effect on personal exposures.

Estimating infants’ and toddlers’ inhalation exposure to fragrance ingredients in baby personal care products

ABSTRACT Fragrance ingredients are commonly added to many personal care products to provide a pleasant scent, including those intended for babies. While fragrance chemicals have a long history of safe use, at sufficiently high concentrations some may act as respiratory irritants or sensitizers. Little data have been reported on the inhalation exposures to fragrance compounds to infants and toddlers during bathing and lotion applications. This study demonstrates an in vitro method for measuring breathing zone air concentrations of fragrances from bath products and lotions. It employed simulated infant bathing and lotion application events and a robot to mimic a toddler’s movement within a bathroom setting. The air concentrations in an infant’s breathing zone were between <1 and 5 μg/m3 for each of seven common fragrance ingredients, while that in the breathing zone of toddlers in the bathroom was ≤ 1μg/m3. The air concentrations from the bathing additive were linearly related to their Henry’s law constants and from the lotion inversely related to their octanol-air coefficients. The proposed approach can help refine risk estimates from inhalation exposure to fragrances used in baby products and guide future risk assessments of new products’ safety for their use in baby bath products.

A post-remediation assessment in Jersey City of the association of hexavalent chromium in house dust and urinary chromium in children

Although all chromite ore processing residue (COPR) sites near residential neighborhoods in Jersey City, New Jersey have undergone remediation, recent studies found widespread, but low levels of hexavalent chromium (Cr+6) in house dust both in Jersey City and in communities with no known sources of Cr+6. This study was designed as a follow-up to determine whether there is an association between current Cr+6 levels in house dust and urinary chromium concentrations in young children. Dust samples (N=369) were collected from 123 homes. The median Cr+6 concentration was 3.3 μg/g (mean±SD 5.2±7.5) and the median Cr+6 loading was 1.1 μg/m2 (1.9±3.1). These levels were not elevated compared with previously reported levels in background communities (median concentration=3.5 μg/g; median loading=2.8 μg/m2). Urinary chromium concentrations were measured in spot urine samples collected from 150 children, ages 3 months to 6 years. The median uncorrected urinary chromium concentration was 0.19 μg/l (0.22±0.16). Current urinary chromium concentrations were significantly lower than those previously reported before and during remediation (t-test; P<0.001). Urinary chromium concentrations were not significantly higher in homes with high (75th or 90th percentile) Cr+6 dust levels (concentration or loading) compared with other homes. Multiple linear regression was used to examine the relationship between Cr+6 levels (concentration and loading) in house dust and urinary chromium concentrations (uncorrected and specific gravity corrected). Contrary to pre-remediation studies, we did not find a positive association between Cr+6 levels in house dust and urinary chromium concentrations. The findings indicate that current Cr+6 levels in house dust are not positively associated with children’s chromium exposure as measured by urinary chromium, and the children’s exposure to Cr+6 in house dust is below the level that could be identified by urine sampling.