Development and in-home testing of the Pretoddler Inhalable Particulate Environmental Robotic (PIPER Mk IV) sampler.
ABSTRACT 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 children's activity in a room, particularly when rugs or carpets are present.
Article: Allergen exposure in infancy and the development of sensitization, wheeze, and asthma at 4 years.[show abstract] [hide abstract]
ABSTRACT: The relationship between mite and pet allergen exposure in infancy and the subsequent development of sensitization and asthma is complex. We prospectively investigated the effect of allergen exposure at 3 months of age on the development of sensitization, wheeze, and physician-diagnosed asthma in the first 4 years of life in a birth cohort of children with and without an atopic mother. Children participated in the Prevention and Incidence of Asthma and Mite Allergy study. Allergen exposure at 3 months of age was determined from mattress dust samples. Specific IgE to inhalant allergens was measured at 4 years of age, and information about wheeze and physician-diagnosed asthma was collected with yearly questionnaires. Mite and cat allergen exposure in infancy were associated with an increased risk of specific sensitization to house dust mite and cat, respectively, at 4 years of age. There were borderline significant associations between cat allergen exposure and persistent wheeze in the total study population and between dog allergen exposure and persistent wheeze in children with a nonatopic mother. In children with an atopic mother, there was some indication of a positive association between mite allergen exposure and physician-diagnosed asthma. Early house dust mite and cat allergen exposure might lead to sensitization and, in case of cat allergen exposure, to persistent wheeze. Early mite and dog allergen exposure might lead to asthma and persistent wheeze, respectively, but only in subgroups defined by maternal atopy.Journal of Allergy and Clinical Immunology 06/2005; 115(5):946-52. · 11.00 Impact Factor
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ABSTRACT: Recent evidence implicates fine particulate matter (PM2.5), principally from vehicular exhaust, as a major cause of increased mortality and morbidity. However, there are limited data on the impact of PM2.5 on infant respiratory illnesses. We conducted a cohort study of 504 infants recruited at 4 months of age from primary health care units in southeastern Santiago, Chile. Project physicians followed infants through the first year of life via monthly check-ups and by appointments on demand. We obtained data for fine particulate matter, sulfur dioxide (SO2), and nitrogen dioxide (NO2) from the governmental monitoring network. The most frequent diagnosis during follow-up was wheezing bronchitis, occurring 19.5 times per 100 infants per month. After adjusting for sex, socioeconomic level, family history of asthma, minimum temperature, and number of older siblings, we found that an increase of 10 microg/m of PM2.5 24-hour average was related to a 5% increase (95% confidence interval 0-9%) in the risk for wheezing bronchitis (1-day lag). This association was present for different lags, with a maximum observed for a 9-day lag (9%; 6-12%). No consistent association was detected with NO2 or SO2 ambient levels. Lower socioeconomic status and having older siblings were also associated with the risk of wheezing bronchitis. The association of PM2.5 and wheezing bronchitis was stronger among infants with a family history of asthma than among infants without. Air pollution in the form of fine particulates, mostly from vehicular exhaust, may adversely affect infants' respiratory health with potential for chronic effects later in life.Epidemiology 12/2004; 15(6):702-8. · 5.57 Impact Factor
Article: Performance of Air-O-Cell, Burkard, and Button Samplers for total enumeration of airborne spores.[show abstract] [hide abstract]
ABSTRACT: Performance of three devices used for the total enumeration of airborne spores-the Air-O-Cell sampling cassette, the Burkard personal volumetric air sampler, and the Button Aerosol Sampler--was evaluated under controlled laboratory conditions. The first two are glass-slide impactors; the third collects spores on a filter. The samplers were challenged with 0.44-5.10 microm polystyrene latex particles and five microorganisms of 0.84-3.07 microm mean aerodynamic diameter: Streptomyces albus, Bacillus subtilis, Cladosporium cladosporioides, Penicillium brevicompactum, and Penicillium melinii. An optical particle counter measured the particle concentrations upstream and downstream of each sampler, and thus determined the physical collection efficiency of the three samplers. Collection efficiency of the Button Aerosol Sampler was close to 100% for the entire particle size range studied. The cut-off size of each impactor was 2.3-2.4 microm. Acridine orange (with epifluorescent microscopy) and lactophenol cotton blue (with bright light microscopy) staining techniques were used for the microscopic enumeration of spores. No significant difference in microscopic counts was found (at the 95% significance level) when using these two techniques with the Button Aerosol Sampler filters. When the lactophenol cotton blue staining was used to compare total microbial counts yielded by all three samplers, the Button Sampler showed significantly higher counts for the smaller size microorganisms (B. subtilis and C. cladosporioides). For the larger microorganisms (P. brevicompactum and P. melinii) all three samplers yielded similar results. Uniformity of particle deposition on the collection surface was highest for the Button Aerosol Sampler due to the design of its inlet. Thus, the filter collection method used with the Button Aerosol Sampler is suitable and can be advantageous for the enumeration of total airborne spores.AIHAJ - American Industrial Hygiene Association 61(6):855-64.