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Indoor environmental quality within an elementary school :
b measurements of Felis domesticus I, Dermatophagoides pteronyssinus, Dermatophagoides farinae I, and Blatella germanica in carpeting
h [electronic resource] /
by Jennifer Fowler.
[Tampa, Fla] :
University of South Florida,
Title from PDF of title page.
Document formatted into pages; contains 47 pages.
Thesis (M.S.P.H.)--University of South Florida, 2009.
Includes bibliographical references.
Text (Electronic thesis) in PDF format.
ABSTRACT: The United States Environmental Protection Agency acknowledges that indoor environments can impact the health of students and can affect concentration, attendance, and student performance (USEPA 2008). In a school year, children are required by the Florida Department of Education to be in school for a total of 180 days, which is 795 hours spent in a classroom (FLDOE 2008). In the elementary school setting, kindergarten classes typically spend a portion of the school day with floor-based activities. The American Lung Association (ALA) states that over 6.8 million children under the age of 18 are affected by asthma (ALA 2008). Allergic reactions and/or sensitization to allergens such as dust, animal dander, and cockroaches are among triggers associated with asthma cases. Literature suggests looking at the areas where individuals spend a considerable amount of time to identify potential exposure sources.Currently, many of these studies have been done regarding the home indoor environment; however, few specifically document the concentrations in carpeting in elementary schools and the exposure time associated with floor-based activities. The objective of this research was to quantify the concentrations of cat (Felis domesticus I), dust mite (Dermatophagoides pteronyssinus I, Dermatophagoides farinae I), and cockroach (Blatella germanica) allergens in carpeting in an elementary school kindergarten class and to document and quantify student group activities that are floor-based. One Florida elementary school classroom was identified as the study site. A total of eight reservoir dust samples were collected during the school year to be analyzed for Felis domesticus I, Dermatophagoides pteronyssinus I, Dermatophagoides farinae I, and Blatella germanica allergens. The sampling reservoir was the carpeting used for group floor-based activities by the school children.Dust samples from the carpet were analyzed by The Johns Hopkins University Reference Laboratory for Dermatology, Allergy, and Clinical Immunology (DACI). The sample collection methodology followed the "Dust Analysis Instructions for Use" provided by the DACI laboratory, along with the "nozzle sock" sampling media. Following discussions with the kindergarten teacher regarding curriculum and scheduled classroom activities, group floor activities were identified. The kindergarten class was observed periodically throughout a school year to document and quantify classroom activities that were floor-based. The information documented includes: occupancy of classroom, occupied floor area, occupant density, and time spent on carpeting.Felis domesticus I (Fel d I) measurements ranged from 2,206 10,558 ng of allergen/g of settled dust, Dermatophagoides pteronyssinus I (Der p I) measurements ranged from 3,408 86,704 ng/g and Dermatophagoides farinae I (Der f I) measurements ranged from 704 6,720 ng/g, and Blatella germanica (Bla g I) measurements were below detection limits. Based upon the DACI criteria, dust mite concentrations were moderate to high and cat concentrations were low to moderate. Kindergarten children spent approximately 38% of classroom time in floor-based activities.
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Advisor: Steve Mlynarek, Ph.D.
x Environmental and Occupational Health
t USF Electronic Theses and Dissertations.
Indoor Environmental Quality within an Elem entary School Classroom: Measurements of Felis domesticus I, Dermatophagoides pteronyssinus I Dermatophagoides farinae I, and Blatella germanica in Carpeting by Jennifer Fowler A thesis submitted in partial fulfillment of the requirements for the degree of Masters of Science in Public Health Department of Environmenta l and Occupational Health College of Public Health University of South Florida Major Professor: Steve Mlynarek, Ph.D. Member: Yehia Y. Hammad, Sc.D. Member: Yangxin Huang, Ph.D. Date of Approval: April 3, 2009 Keywords: kindergarten, indoor allergen s, dust mite, cat, cockroach Copyright 2009, Jennifer Fowler
Dedication This thesis is dedicated to my husband, Chris, my parents, Connie and Wayne, and my aunt, Jewel, with love. Your support every step of the way will always be appreciated and your belief in the importanc e of education has truly helped to push me to complete what I started.
Acknowledgments I would like to take this opportunity to thank my committee members Dr. Steve Mlynarek, Dr. Yehia Y. Hammad, and Dr Yangxin Huang for providing guidance through this process. I would al so like to thank all of the staff and professors in the Environmental and Occupational Health De partment for an exceptional Industrial Hygiene program that has provided me with a level of education far above any other program out there. I would like to thank the Johns Hopki ns University School of Medicine DACI Laboratory for helping me with my questions, literature suggestions, and for their outstanding service. Finally, I woul d like to thank the Ki ndergarten class that allowed me to come into their cl assroom for an entire school year.
i Table of Contents List of Tables ii List of Figures iii Abstract iv Introduction 1 Purpose 3 Literature Review 4 Background 4 Exposure 6 Health Effects 8 Related Studies 10 Methods 13 Study Design 13 Classroom Observation 14 Sampling Strategy 16 Sample Analysis 17 Results 19 Classroom Observation 19 Classroom Design and Classroom Maintenance 22 Analytical Results 25 Discussions and Conclusions 28 Discussions 29 Conclusions 32 Recommendations for Future Research 33 References 34 Appendices 36 Appendix A: Sample Information 37 Appendix B: DACI Laborator y Instructions for Use 38 Appendix C: Analytical Laboratory Results 40
ii List of Tables Table 1 Risk levels for asthma were developed from home studies and have been applied to school research 9 Table 2 Allergen Concentrations in Settled Dust Carpeting 10 Table 3 Classroom Observation 19 Table 4 Curriculum Agenda August, 2007 April, 2008 20 Table 5 Curriculum Agenda April, 2008 May, 2008 20 Table 6 Temperature and Relative Humidity within the Classroom 25 Table 7 Sample Results November, 2007 March, 2008 26 Table 8 Sample Results April, 2008 July, 2008 26 Table 9 Descriptive Summar y of Sample Results 26 Table 10 DACI Risk Range Characterization 27 Table 11 DACI Risk Range for Sample Results November, 2007 Â– March, 2008 27 Table 12 DACI Risk Range for Sample Results April, 2008 July, 2008 27
iii List of Figures Figure 1 Curriculum Agenda vs Observed Floor Time 22 Figure 2 Classroom Design 24
v Indoor Environmental Quality within an Elementary School Classroom: Measurements of Felis domesticus I, Dermatophagoides pteronyssinus I Dermatophagoides farinae I, and Blatella germanica in Carpeting Jennifer Fowler ABSTRACT The United States Environmental Protect ion Agency acknowledges that indoor environments can impact the health of stude nts and can affect concentration, attendance, and student performance (USEPA 2008). In a school year, children are required by the Florida Department of Educa tion to be in school for a total of 180 days, which is 795 hours spent in a classroom (FLDOE 2008). In the elementary school setting, kindergarten classes typically spend a por tion of the school day with floor-based activities. The American Lung Association (A LA) states that over 6.8 m illion children under the age of 18 are affected by asthma (ALA 2008). Allerg ic reactions and/or sensitization to allergens such as dust, animal dander, a nd cockroaches are among triggers associated with asthma cases. Literature suggests looki ng at the areas where individuals spend a considerable amount of time to identify potential exposure sources Currently, many of these studies have been done regarding the home indoor environment; however, few specifically document the concentrations in carpeting in elementary schools and the exposure time associated with floor-based activities. The objective of this research was to quantify the concentrations of cat ( Felis domesticus I), dust mite ( Dermatophagoides pteronyssinus I Dermatophagoides farinae
vi I ) and cockroach ( Blatella germanica) allergens in carpeting in an elementary school kindergarten class and to document and quantif y student group activit ies that are floorbased. One Florida elementary school classroom was identified as th e study site. A total of eight reservoir dust samples were collected during the school year to be analyzed for Felis domesticus I, Dermatophagoides pteronyssinus I Dermatophagoides farinae I, and Blatella germanica allergens. The sampling reservoir was the carpeting used for group floor-based activities by the school children. Du st samples from the carpet were analyzed by The Johns Hopkins University Referen ce Laboratory for Dermatology, Allergy, and Clinical Immunology (DACI). The sample collection methodology followed the Â“Dust Analysis Instructions for UseÂ” provided by the DACI laboratory, along with the Â“nozzle sockÂ” sampling media. Following discussions with the kindergarten teacher regarding curriculum and scheduled classroom activities, group floor activities were identified. The kindergarten class was observed periodically throughout a school year to document and quantify classroom activities that were floor-based. The information documented includes: occupancy of classroom, occupied floor area, occupant density, and time spent on carpeting. Felis domesticus I ( Fel d I) measurements ranged from 2,206 Â– 10,558 ng of allergen/g of settled dust, Dermatophagoides pteronyssinus I ( Der p I) measurements ranged from 3,408 Â– 86,704 ng/g and Dermatophagoides farinae I ( Der f I) measurements ranged from 704 Â– 6,720 ng/g, and Blatella germanica ( Bla g I) measurements were below detection limits.
vii Based upon the DACI criteria, dust mite concen trations were moderate to high and cat concentrations were low to moderate. Kinde rgarten children spent approximately 38% of classroom time in floor-based activities.
1 INTRODUCTION The management of immunoglobulin E (IgE)-mediated human allergic diseases, such as extrinsic asthma and rhinoconjunctivi tis, involves a combina tion of four potential approaches: allergen avoidance, symptomdirected pharmacotherapy, allergen specificdirected immunotherapy, or hyposensitizat ion and omalizumab (omalizumab is a monoclonal antibody used to reduce allerg ic hypersensitivity) (Hamilton, 2005). To facilitate avoidance of allergen exposure a nd document remediation actions in the allergic individualÂ’s personal and work or school environments, it is useful to document the actual level and location of the relevant allergens that can trigger symptoms. This is particularly important for areas where alle rgic individuals spend considerable time (Hamilton, 2005). Kindergarten children, ages 5 to 6 years old, spend 795 hours in a classroom. Allergy symptoms gradually intens ify as indoor allergens accumulate and/or the patientÂ’s allergic sensitivity increase s (Hamilton, 1992). Avoidance studies strongly suggest that continuing exposure plays a role in most cases of chronic asthma (PlattsMills et. al., 1995). The suggest ed dust reservoir sampling method for allergens is vacuum sampling (HUD, 2004) and to date this is the best index of exposure to allergens. This study quantified the concentrations of cat ( Felis domesticus I) ( Fel d I), dust mite ( Dermatophagoides pteronyssinus I Dermatophagoides farinae I ) ( Der p I, Der f I), and cockroach ( Blatella germanica) ( Bla g I) allergens in carpet ing and document and quantify classroom activities which are floor-based.
2 The elementary school and kindergarten class was chosen based on age of the school building, age of carpeting, and the wil lingness of the school administration and the teacher to participate. Prior to the start of the study, discussions with the kindergarten teacher identified curriculum and scheduled cl assroom activities that involved group floor time. This information provided the basis for estimating the exposure time of kindergarten children to allergens in the carpeting. The dust sampling area was determined by the location of th e group floor based activities. Strong documentation exist that asthma and allergies can be triggered and exacerbated by exposure to many environmenta l factors and sensitization to indoor allergens is a risk factor for the developmen t of asthma in childre n and adults (ATSDR, 2007). Few exposure data exist for school chil dren who are at greater risk based upon their scheduled classroom curri culum. This research prov ides needed information on student exposure time and concentration le vels of allergens wi thin carpeting, and information that furthers the knowledge of these topics.
3 Purpose The purpose of this research was to quantify the concentrations of Fel d I, Der p I, Der f I, and Bla g I allergens in carpeti ng, and to quantify floor based classroom activity time. The specific objectives of this research were: 1. To quantify and document the classroom activities which are floor-based; a. The location of group floor-based activities was determined. b. The group floor area was determined. c. The number of students during ea ch classroom observation was determined. d. The duration of time students spent in the group floor-based activities was determined. e. The activities students performed while in gr oups on the floor were documented. 2. To quantify the allergen exposures to the kindergarten students using the DACI lab method; a. The concentrations of Fel d I. b. The concentrations of Der p I. c. The concentrations of Der f I. d. The concentrations of Bla g I.
4 LITERATURE REVIEW Background Dust is a heterogeneous mixture compri sing a variety of i norganic and organic particles, metals, and fibers of different si zes (Elliott, Arbes Jr. et al. 2007). Common organic particles that may be found within dust include dust mites, cat allergen, and cockroach allergens. Dust mites Dermatophagoides pteronyssinus ( Der p I) and Dermatophagoides farinae ( Der f I) belong to phylum Arthropoda and subphylum Chilcerata (Macher, Ammann et al. 1999) D. farinae and D. pteronyssinus are found most frequently and are most widely distributed geographi cally (Macher, Ammann et al. 1999). A female D. farinae measures 425 m in length and weighs between 10 and 16 g, while the female D. pteronyssinus are only 300 to 350 m long (Macher, Ammann et al. 1999). Indoor dust mites are commonly found in areas, such as, carpeting, stuffed animals, and upholstered furniture. Mites reportedly produce up to 200 times their own weight in allergen-rich fecal pellets of a mean average diameter of 20 microns during their 2 to 3.5 month life span (Hamilton 2005). Literature revi ew suggests that there is a correlation between dust mite concentration, temperature, and relative humidity. Mite densities exhibit a seasonal cycle that para llels relative humidity changes, with the highest mite concentrations occurring duri ng periods of high relative humidity (Macher, Ammann et al. 1999). Experiments have shown that mites feed sparingly at relative humidity (RH) levels less than 70%, produc ing little fecal materi al and associated
5 allergen (Macher, Ammann et al. 1999) Mites consume 75% less food (with a corresponding reduction in fecal pellet pr oduction) at 75% RH than at 85% (Macher, Ammann et al. 1999). All mites gr adually dehydrate and die when held for more than 11 days at humidities below 50% (Macher, Ammann et al. 1999). Felis domesticus the domestic cat, has become the most common indoor pet in the United States as of 1989 (Hamilton, Chapman et al. 1992). All warm-blooded animals produce potential allergens in th eir dander, urine, feces, an d saliva (German and Harper 2002). The sublingual mucous salivary glands and hair root sebaceous glands of the cat produce a potent 38-kD allergen (Hamilton 2005) It adheres tenaciously to fibers in carpets and dust particle s from 2 to 10 microns in size that can be inhaled. The principal cat allergen, Fel d I is heat stable and thus steam cl eaning of carpets ha s no added benefit over regular vacuuming in removing cat alle rgen from the home (Hamilton, Chapman et al. 1992). Of the 50 varieties of cockroaches in the US, only 8 are considered important indoors species. Blatella germanica (Bla g I ) is considered the most cosmopolitan cockroach (Hamilton, Chapman et al. 1992). Co ckroaches can become abundant in any environment where sanitary practices ar e inadequate (Macher, Ammann et al. 1999). Bla g I is used as an indicator of the level of cockroach infestation (Hamilton, Chapman et al. 1992). The particles that carry cockroach allergen are relativ ely large (at least 10 m in size) and remain airborne for a short period of time after disturbance (German and Harper 2002).
6 Exposure Antigen exposures have increased due to people spending more time indoors and recent changes in homes and offices (e.g., higher mean indoor temperatures, reduced ventilation, laundering with cool wash dete rgents that may not remove allergens effectively, and widespread use of carpeti ng) (Macher, Ammann et al. 1999). The number of adult and children resident s, type of dwelling, age of home, duration of habitation, prior occupancy, and urban or rural locati on are some factors that may influence aeroallergen burden in the home. In general, a greater number of inhabitants will deposit higher levels of skin and food particles throughout the home (Hamilton, Chapman et al. 1992). Literature suggests the same application may be app lied to an elementary school setting. Cat allergens adhere to dust particles that range in size from 2 to 20 microns (Hamilton, Chapman et al. 1992). The commona lity of the domesticated cat in households throughout the United States and the si ze of dust particles th at the cat allergen adheres to allows for cross contamination between homes and schools. In the Abramson, et al. (2006) report cat allergen was identified despite the la ck of domestic cats in the school setting. However, it is unclear to the amount allergens which are brought from home by the students to the school (Trant er 2005). The common source of cockroach antigens is in settled dust while their common breeding grounds include kitchens, basements, and bathrooms. The antigenic product of cockroaches is f ecal particles, saliva, and dried body fragments. Pr oteins derived from cockroaches are associated with particles greater than 5 m diameter and beco me airborne only when a room is disturbed (Macher, Ammann et al. 1999). To facilitate avoidance of allergen exposure and document remediation actions in the allergic individualÂ’s personal and work or school
7 environments, it is useful to document the actu al level and location of relevant allergens that can trigger symptoms (Hamilton 2005). Several studies have documented a doseresponse relationship between cumulative expos ure to dust mite allergen and subsequent sensitization of exposed persons (Macher, Ammann et al. 1999). The case for a causal relationship would best be supported by evidence for a dose-response relationship between allergen exposure and symptoms (Pla tts-Mills, Sporik et al. 1995). Exposure to dust mite, cat, and cockroach allergens comes after carpeting becomes disturbed. However, the allergen concentration of dus t mite, cockroach, and cat in dust does not reflect the direct measurement of the allergen entering the lungs. At this time, there is no measurement to directly assess the total a llergen content enteri ng the lungs based upon range of allergen particle si ze. Although measurements of re servoir dust may be rather distant from an actual measur ement of allergen entering th e lungs, nonetheless, for mite and cockroach allergens are the best index of exposure that is available (Platts-Mills, Sporik et al. 1995). For cat allerg en it is clear that airborne allergen is carried on a wide range of particle sizes and th at the relationship between air borne levels and floor samples is extremely variable (Platts-Mills, Sporik et al. 1995). Avoida nce studies strongly suggest that continuing exposure plays a role in most cases of chronic asthma (PlattsMills, Sporik et al. 1995). This is strong evidence that continuing exposure plays an important role in symptoms (Platts-Mills, Sporik et al. 1995). However, an equally important concept is that the dose response fo r symptoms may not be comparable to the dose response for sensitization (P latts-Mills, Sporik et al. 1995).
8 Health Effects The immune response to inhaled cat ( Felis domesticus ), dust mite ( Der p I Der f I ) and cockroach ( Bla g I ) allergens yields many differe nt symptoms which include allergic rhinitis, extrinsic asthma, allergic sinusitis, atopic dermatitis, bronchial hyperactivity (BHR), and hypersensitivity pneumonitis. The bodyÂ’s response depends on the source material, host fact ors (e.g. genetic factors and pr ior exposure), and the duration and intensity of exposure (Macher, Ammann et al. 1999). There are two phases which are considered with regard to inhaled allergens. The first is sensitization, in which, time is required for the body to develop an immunologi cal sensitization (Macher, Ammann et al. 1999). The second is the production of chroni c bronchial inflammation (Platts-Mills, Sporik et al. 1995; Gold 2000). Experiments s uggest that continued allergen exposure is necessary to maintain inflammation which is the cause of BHR and is an important longterm cause of inflammation. For the first phase (i.e. sensitization) th ere is clear evidence for a dose-response relationship such that the high er the levels of alle rgen in the homes of a community, the larger the percent of child ren who will become sensitized. In contrast, the evidence for a dose-respons e relationship among se nsitized individuals is indirect and unlikely to be demonstrated by cross-sect ional studies of a population (Platts-Mills, Sporik et al. 1995). Sensitiz ation and high exposure to co ckroach allergen has been strongly associated with the risk of asthma in some studies (Tovey and Marks 1999). The measured concentrations can be compared with Â‘risk levelsÂ’, which are approximate indicator levels based on concentrations in homes that consistently correlated with asthma exacerbation or sensitization (Table 1) (Tranter 2005).
9 Table 1: Risk levels for asthma were de veloped from home studies and have been applied to school research Allergen Risk levels [1, 4, 6, 22] Alte rnatives levels of interest cited Dust mite ( Der p I Der f I) Sensitization (for atopic) >2,000 ng/g settled dust Symptoms >10,000 ng/g settled dust Â‘Increased levelÂ’ >25 ng/m2 area sampled Cat ( Fel d I) Sensitization >8,000 ng/g settled dust Â‘Moderate levelÂ’: 1,000Â–8,000 ng/g settled dust, >8,000 ng/m2 area sampled Dog ( Can f I) Sensitization >10,000 ng/g settled dust Â‘Moderate levelÂ’: 1,000Â–10,000 ng/g settled dust Cockroach ( Bla g I or II) Sensitization >2U/g (activity units of antigen per gram settled dust) Â‘Symptom thresholdÂ’>2, >8 U/g Â‘Sensitization thresholdÂ’>1, >5, >10 U/g Â‘Level of concernÂ’>1U/g Â‘Low thresholdÂ’>5,000 ng/g settled dust In a study where carpet allergen meas urements were recorded between two elementary schools the dust mite concentra tions ranged from non-detectable to 26 ng/g, cat allergens concentrations ranged from 710 ng/g to 1,710 ng/g, and cockroach 0.82 U/g to 9.00 U/g (Ramachandran, Adgate et al 2005). Limited literature exists on concentrations of allergens in carpets am ong elementary schools in the United States. Table 2 shows the review of ten to eighteen studies in the United States on indoor allergens in settled school dus t reported by D.C. Tranter.
10 Table 2: Allergen Concentra tions in settled dust carpeting Allergen Location School Concentration (ng/g) Dust mite ( Der p I Der f I) 17 studies Florida, USA, May-June Texas, USA, April-May North Carolina, USA, late spring 42-14,646 ng/g (arithmetic mean, Der p I 7,204 ng/g and Der f I 3,457 ng/g) 10-50,900 ng/g (median, 575 ng/g) 7,000 ng/g (geometric mean) Cat ( Fel d I) 18 studies United States, 34% cat ownership among households 8-6,000 ng/g (geometric mean 6,000 ng/g) Cockroach ( Bla g I or II) 10 studies North Carolina, USA Texas, USA 4,600 ng/g (geometric mean) 1.6Â–15.4 ng/g (median, 5.7 U/g) Related Studies Although studies identify that hard floors retain less allergen content and are recommended in avoidance studies, carpeti ng remains a common trend for homes, office, and school locations (Macher, Tsai et al. 2002 ; Causer, Lewis et al. 2004; Causer, Shorter et al. 2006). The popularity of carpeting seems to be because of the appearance, texture, insulating, and sound absorbing properties (Causer, Lewis et al. 2004). Additional literature suggests that the carpet construction, wear, and cleaning methods should be considered in the evaluation of allergen load ing content. In 2002 at the Indoor Air conference in Monterey, California the results of concentrations of Fel d I Der f I and Der p I allergens was reported for 93 of 100 U.S. office buildings. Samples were collected during the summer and winter months throughout the United States. Cat allergens we re found in almost all BASE buildings even though cats seldom enter offices (Macher Tsai et al. 2002). Dust mite allergens were detected in approximately half of th e samples (Macher, Tsai et al. 2002). Possible
11 sources of these alle rgens again are the occupants a nd their belongings (IOM 1993; IOM 2002) but also colonization of suitable habitats in offices, such as carpets and upholstered furniture that provide mites with food (prima rily human skin flakes), moisture, warmth, and protection (Macher, Tsai et al. 2002). Floor covering construction which may a ffect the how allergens are inhaled and which may provoke an allergic response depends on the type of disturbance, environmental conditions, the level of contamin ation, and the nature of the floor covering and where the allergen resides within it (C auser, Shorter et al. 2006). The most common carpeting construction in the world is reportedly synthe tic. Circumstantial evidence within the report suggests that a relationship between carpe t construction and allergen content exists (Causer, Shorter et al. 2006). From the Causer study (2006) it appears that the extent of the pile flattening that occurs after carpet wear differs between carpet types, but neither pile height, pile conformation, pi le density, nor yarn twist greatly influence how much Der p I collects within the carpet pile. Vacuuming has been studied extensivel y as an interventi on to improve hygiene and to decrease the frequency and severity of asthma, allergies, and other health outcomes (Corsi, Siegel et al 2008). However, dry vacuum cleaning one to two times per week may be sufficient to remove soil from carpeting it will not be regular enough to reduce the allergen load in carpet to the poi nt where a clinical improvement could be expected (Causer, Lewis et al. 2004). Causer (2004) found that the dust recovery rates were not proportional to allergen recovery ra tes, and that the ratio was influenced, to some extent, by the carpet c onstruction. Carpeting constructed of low pile height and density appeared to have less of an allergen content because dry vacuuming was able to
12 recover a more significant amount dust. In the Causer (2004) study, carpet cleaning methods were evaluated based upon no vac uuming, wet extraction, and dry extraction. Each extraction was performed separate ly. The study concluded that vacuuming procedures must be performed on a regular ba sis, and techniques employed to avoid the increased exposure to airborne allergen that occurs during vacuuming. In addition, while unworn carpets removed allergens through vac uuming the efficiency of removal with worn carpeting was considerably reduced.
13 METHODS Study Design This research project was a study of the concentrations of cat ( Felis domesticus I), dust mite ( Dermatophagoides pteronyssinus I and Dermatophagoides farinae I ) and cockroach ( Bla g I ) allergens in carpeting in an elem entary school kinderg arten class. The hypothesis of this research was that kinderg arten children increase their exposure to allergens as a result of the time spen t on floor-based school activities and the concentration levels of allergens in the carpe ting. This project was not designed to assess the allergic response in the students or teaching staff. While literature is available describing sampling techniques for reservoir dust, dust collection devices, performance of vacu um in collecting allergen samples in residential buildings, limited literature is availa ble for public school sett ings. At this time, there has been no standard developed for reservoir dust sampling. Therefore, the DACI Laboratory Dust Analysis Method was utilized for sampling technique, and sample duration. The kindergarten class and teaching staff di d not participate in any part of the research project. Therefore, the University of South Florida Institutional Review Board (IRB) waived further requirements. Only one kindergarten class was observed during this research and reservoir dust samples were obtained from the same classr oom throughout the duration of this project.
14 The limitations associated with this research include the ag e of the carpeting; custodial maintenance, building construction, and teachi ng curriculum, which va ries in all other kindergarten classrooms or publ ic schools. However, this data provides a foundation for further research and assessments. Classroom Observation In the elementary schools, kindergarten classes typically spend a portion of the school day with floor-based activities. Follo wing discussions regarding curriculum and scheduled classroom activities with the kinde rgarten teacher, group fl oor activities where identified. The kindergarten teacher provided a curriculum plan. Tables 4 and 5 detail the classroom curriculum. Student group floor-bas ed activities are conducted at the front of the classroom on the carpeting which is adjacent to the white board and the teacherÂ’s work desk and is a common area for people to walk through the classroom. In addition, there are several floor Â“centersÂ” for indi vidual student activities which are located throughout the classroom. The kindergarten class has a total of nineteen students enrolled. The kindergarten class was observe d throughout a school year to document and quantify classroom activities which are floor-based. The information documented includes; occupancy of classroom, occupied floor area, occupant density, and time spent on carpeting. The data compares the time spent in the group floor setting to the total time spent in the classroom during a school day. Students enter the classroom at 8:30 AM and place their belongings at the back of the classroom in open lockers. Students then return to the cla ssroom and go to the carpeted area designated for the group. Group fl oor time lasts for approximately fifteen to twenty minutes. During the morning floor time the student announcements, Pledge of
15 Allegiance, and attendance are conducted. The group floor based activities of the students includes standing, sitting in place, and jogging in place. Students return to their assigned desks until approximately 10:00 AM at which tim e they return to the group floor area for a group comprehension lesson that extends until approximately 10:15 AM. Students leave the group floor area for other classroom inst ruction until lunch at which time they leave the classroom through the exterior door and walk to the cafeteria. Students return to the classroom at 11:52 AM and return to their desks. Recess is scheduled from 12:10 PM until 12:30 PM. Following recess students return to the carpeted area for approximately thirty minutes. Specials classes, such as fine art and physical education, occur at the end of the school day. Student dism issal occurs at 2:45 PM. On the November 19, 2007 classroom observa tion of an adjoining classroom of third grade students assisted the kindergarten class in a special activity which involved sitting on the carpeted group area. The height of the students obser ved in the sitting position is approximately twenty-four inch es from of the ground. On December 14, 2007, students who completed their desk work early were permitted to go to the carpeted floor area to read and were observed to sit, st and, or lay down with th eir faces against the carpet. Group floor activities do not include assigned seating which allows students to sit in different locations within the designated group floor area. Prior to the start of the classroom activities at 9:49 AM on January 22, 2008 was observed to include eating snacks at their student desks. Following the 9:49 AM group floor activity students subsequently moved to different individual floor Â“centersÂ” and student desks for other classroom activities. The February 12, 2008 classroom observation involved special ValentineÂ’s Day activities fo r the group floor area and additional group floor time was
16 planned due to the school campus participa ting in the Florida Comprehensive Aptitude Test (FCAT). On February 19, 2008, the teacher was in meetings for the day which required a substitute teacher who spent an exte nded period of the class time on the floor in group activities. During the various cl assroom observations on March 25; April 30; May 15; and May 21, 2008 involve d students standing, sittin g, and walking in place within the designated group floor area. Although the curriculum agenda for the ki ndergarten class was identified by the teacher variations from this regularly occurred as a result of substitute teachers, special guest speakers, and special cl assroom activities, such as ValentineÂ’s Day and the FCAT. Therefore, the curriculum agenda was utiliz ed to identify the potential duration of exposure. Sampling Strategy The Johns Hopkins University Refere nce Laboratory for Dermatology, Allergy, and Clinical Immunology (DACI) recommends sc hool reservoir dust specimen collection site selection should target areas where large numbers of allergic workers or students congregate. The sample area was determined by the location of the group floor based activities. During a student group floor activit y the carpeted area was marked with Duct Tape which outlined the location of the stude nts. Subsequently, the area was measured and recorded. The area marked during the group floor activity remained in place throughout the duration of the re search project. Figure 2 diagrams the classroom design. Eight reservoir bulk dust samples were coll ected from the carpe ted floor utilizing a Â“nozzle sockÂ” sample media. The Â“nozzle sock,Â” provided by the DACI Laboratory, is a vacuum cleaner adapter that is inserted into the base of the vacuum hose portion of the
17 vacuum cleaner. The Â“nozzle sockÂ” is manufactured from a refined glass spun polyethylene fiber pulp media (Hamilton, Assess ment). The Â“nozzle sockÂ” was inserted into a Numatic International RSV 130 back pack vacuum cleaner, serial number 034413843, which is utilized by the custodial cleaning staff. The same RSV 130 back pack vacuum cleaner was utilized throughout the research project. In addition, three Numatic International low prof ile vacuum floor tools were purchased for the research project to ensure the reser voir dust samples collected obtai ned from the pre-designated sampling area did not have cross contaminati on of dust from other locations throughout the school. Following each sampling event, the low profile vacuum floor tools were cleaned utilizing microfiber cloths. The DACI Laboratory sampling protocol re quires vacuum samples be collected for a minimum of two minutes. Vacuum sample s were timed using a standard stop watch for the duration of two minutes. The enti re designated floor area was continuously vacuumed horizontally for one minute and vertically for one minute. Samples were collected following school dismissal. The Â“ nozzle sockÂ” was subsequently removed from the vacuum cleaner hose and placed into the plastic zip lock bag provided and mailed to the DACI Laboratory. Sample collection o ccurred monthly during the 2007-2008 school year, with the exception of December due to the shortened holiday month. Sample Analysis Sample analysis was performed by the DACI Laboratory. Upon receipt of the reservoir dust samples the DACI laboratory sieves crude dust through a 50-mesh metal sieve onto waxed laboratory weighing pape r to allow dust partic les smaller than 240 microns to pass through (Hamilton 2005). Following the sieving process the fine dust
18 particles are weighed on an anal ytical balance. Results are re ported in mass quantities of allergen per gram of dust. On e hundred milligrams of fine rese rvoir dust is extracted in 2 mL of filtered phosphate-buffered saline (P BS) containing protein, such as 1% bovine serum albumin (Hamilton 2005). Suspended samples are stored for approximately 12 to 16 hours and then centrifuged so that the solid may be collected and removed. The allergen extract is subsequently frozen at -20 C or lower. The DACI laboratory utilizes two-site im munoenzymatetric assays (IEMAs) to quantify Fel d I, Der p I, Der f I, and Bla g I allergens. Each allergen IEMA is initiated by adsorbing the allergen-specific captur e antibody on a plastic microtiter plate (Hamilton 2005). The interpolated levels of allergen are then corrected for the mass of the dust extracted, and final re sults are reported as g or U/g of fine dust (Hamilton 2005). The DACI laboratory calibrate s standards against various reference preparations. Based upon literature research and discu ssions with Johns Hopkins Asthma and Allergy Center the DACI Labor atory was chosen for vacuum sample analysis. The Housing and Urban Development (HUD) Of fice of Healthy Homes and Lead Hazard Control in 2004 provided HUDÂ’s Health Home s Initiative Grantees a Background and Justification for Vacuum Sampling Protocol for Allergen in Household Dust which summarizes the various vacuums and dust collec tion devices available for reservoir dust sampling.
19 RESULTS Classroom Observation Twelve classroom observations of group floor activities were performed from November 17, 2007 through May 21, 2008. Table 3 presents the student occupancy, date of classroom observation, tota l amount of time students spen t on the carpeted floor, and the activities the students perf ormed while in their groups. Table 3: Classroom Observation of Floor Based Group Activities Date Student Occupancy Start Time Stop Time Total Minutes Activities 11/19/07 18 8:59 AM 9:15 AM 16 sitting, standing, jogging in place 11/19/07 18 9:49 AM 10:03 AM 14 sitting, 3rd grade class participates 12/14/07 19 9:05 AM 9:35 AM 30 laying down on floor with face against carpet, sitting, standing in place 1/22/08 17 8:43 AM 9:13 AM 31 sitting, standing 1/22/08 17 9:49 AM 10:30 AM 38 sitting, standing, laying down on floor with face against carpet 2/12/08 18 12:14 PM 12:30 PM 16 sitting, standing, stomping in place 2/19/08 17 8:43 AM 9:46 AM 63 sitting, standing, walking in place 3/25/08 17 8:44 AM 9:24 AM 25 sitting, standing 4/30/08 18 8:41 AM 9:00 AM 19 sitting, standing 4/30/08 18 9:44 AM 9:52 AM 8 sitting, standing 5/15/08 18 12:40 PM 1:18 PM 38 sitting 5/21/08 17 8:36 AM 9:00 AM 24 sitting, standing, walking in place
20 Table 4 and 5 details the curriculum agenda The curriculum agenda was altered during the month of April, 2008. As a result, additiona l group floor time activiti es were initiated. Table 4: Curriculum Agenda August, 2007 April, 2008 Time Curriculum Plan Total Time (min) 8:30 8:40 AM Enter Classroom 10 8:40 9:15 AM Welcome/At tendance (Group Floor) 35 9:15 10:00 AM Student Desks 45 10:00 10:15 AM Group Floor 15 10:15 10:30 AM Centers Individual Floor Activities 15 10:30 11:00 AM Centers Individual Floor Activities 30 11:00 11:15 AM Student Desks 15 11:15 11:52 AM Out of Classroom (Lunch) 37 11:52 12:10 PM Student Desks 18 12:10 12:30 PM Out of Classroom (Recess) 20 12:30 1:15 PM Group Floor 45 1:15 2:00 PM Specials Out of Classroom 45 2:00 2:15 PM Student Desks 15 2:15 2:45 PM Student Desks 30 2:45 PM Dismissal Total Group Floor Time 95 Total Individual Floor Time 45 Total Carpet Time 140 Total Classroom Time 273 Table 5: Curriculum Agenda April, 2008 May, 2008 Time Curriculum Plan Total Time (min) 8:30 8:40 AM Welcome/Enter Classroom 10 8:40 9:00 AM Group Floor 20 9:00 9:10 AM Group Floor 10 9:10 9:25 AM Center Indi vidual Floor Activities 15 9:25 9:35 AM Student Desks 10 9:35 9:45 AM Group Floor 10 9:45 10:00 AM Center In dividual Floor Activities 15 10:00 10:10 AM Group Floor 10
21 Table 5 (Continued): Curriculum Agenda April, 2008 May, 2008 10:10 10:25 AM Center In dividual Floor Activities 15 10:25 10:35 AM Group Floor 10 10:35 10:50 AM Center In dividual Floor Activities 15 10:50 11:00 AM Group Floor 10 11:00 11:20 AM Student Desks 20 11:20 11:52 AM Out of Classroom (Lunch) 32 11:52 12:10 PM Group Floor 18 12:10 12:30 PM Out of Classroom (Recess) 20 12:30 1:15 PM Group Floor 15 1:15 1:55 PM Specials Out of Classroom 40 1:55 2:40 PM Student Desks 45 2:40 2:45 PM Student Desks 5 2:45 PM Dismissal Total Group Floor Time 103 Total Individual Floor Time 60 Total Carpet Time 163 Total Classroom Time 253 The total time students spent in group floor activities ranged from 95 to 103 minutes. The total time students spent within their classroom each day ranged from 253 and 273 minutes. The percentage of the st udents classroom time spent on the designated group floor area was 38% of their day. Figure 1 shows the actual observed time students spent in group floor activities compared to the curriculum agenda.
22 Figure 1: Curriculum Agenda vs Observed Floor Time Curriculum Time vs Observed Floor Time 0 10 20 30 40 50 60 708:40 9:15 AM10:00 10:15 AM12:10 12:30 PM12:30 1:15 PM1:15 2:00 PMSchool DayMinutes Floor Based Activities Observed Floor Activities 11/19/07 Observed Floor Activities 12/14/07 Observed Floor Activities 1/22/08 Observed Floor Activities 2/12/08 Observed Floor Activities 2/19/08 Observed Floor Activities 3/25/08 Observed Floor Activities 4/30/08 Observed Floor Activities 5/15/08 Observed Floor Activities 5/21/08 Classroom Design and Classroom Maintenance Figure 2 shows the interior lay-out of th e kindergarten classroom. The designated group floor area was 82 inches long and 97 inches wide. The group floor area was positioned at the front of the classroom adjacent to the exterior wall where the white board and teacher work desk were located. Samples were collected within the same location throughout the study. The st udent desks, individual Â“ centersÂ”, teacher desk, and bookshelves are carpeted. The back of the cl ass where the classroom sink and restroom are located is vinyl floor covering. The carpeting in the classroom is grey and
23 approximately 18 years old. The kindergart en class enters th e building through an exterior door. The building design includes four classrooms which are connected to a central pod area where the teacher planning room and workroom are located. Each classroom has an individual exterior door. The building is constructed of concrete masonry block units and a brick faade. The ceilings are Tectum Â™ and wood trusses. The heating, ventilation, and air-conditioning unit is controlled by the te achers with a single twist timer. The air handling system operates on a chilled wa ter system with plenum return. Custodial maintenance of the classroom included vacuuming nightly utilizing the Numatic International RSV 130 back pack vacuum cleaner. No further carpet maintenance was performed throughout the duration of this study. Dusting within classrooms only occurs on open horizontal surfaces where bookshelves, top of computers, filing cabinets, etc. are not clu ttered with personal aff ects, papers, or books. The frequency of classroom dusting depends on availabil ity among custodial staff.
24 Figure 2: Classroom Design (Not to Scale) Desk 82Â” Desk Entrance Group Floor Area 97Â” Desk Bookshelf Carpet Student Desk Desk Student Desk Student Student Bookshelf Play Desk Desk Kitchen Vinyl Floor Covering
25 Analytical Results Reservoir dust sampling was performed from November 30, 2007 through July 7, 2008. A total of eight samples were collect ed approximately every month, with the exception of December, 2007. Two weeks in December the school district is closed for winter break, therefore, sa mpling did not occur during this month. Temperature and relative humidity within the classroom range d from 70 F to 76 F and 38% to 56% during the school year. During the unoccupied mode of the classroom the temperature and relative humidity were 83F and 67%, respectively. Ta ble 6 provides a summary of temperature and relative humidity within the classroom during sampling events. Table 6: Temperature and Relative Humidity within the Classroom Sample Date Temperature (F) Relative Humidity (%) 11/30/07 72 52 01/14/08 70 49 02/12/08 71 53 03/07/08 73 54 04/14/08 76 38 05/05/08 73 54 06/03/08 72 56 07/07/08 83 67 Specific sampling results are located in Appendix A. Tables 7 and 8 provide a summary of sample results th roughout the duration of the study. Table 9 summarizes the sample results presented in Table 7 and 8.
26 Table 7: Sample Results November, 2007 March, 2008 Sample Date 11/30/07 01/14/08 02/12/08 03/07/08 Allergen ng/g ng/g ng/g ng/g Der p I 5239 16889 3408 4438 Der f I 2651 5951 704 1574 Fel d I 3924 7858 3086 2206 Bla g I <0.7 U/g <0.4 U/g <0.4 U/g <0.4 U/g Table 8: Sample Results April, 2008 July, 2008 Sample Date 04/14/08 05/05/08 06/03/08 07/07/08 Allergen ng/g ng/g ng/g ng/g Der p I 86704 30656 15232 26186 Der f I 6253 2718 2735 6720 Fel d I 4135 3856 10558 5797 Bla g I <0.4 U/g <0.4 U/g <0.4 U/g <0.4 U/g Table 9: Descriptive Summary of Sample Results Allergen Mean Median Standard De viation Maximum Minimum Der p I 23594 16061 27427 86704 3408 Der f I 3663 2727 2305 6720 704 Fel d I 5178 4030 2781 10558 2206 The sample location and total area sampled remained consistent throughout the study. The mean sampling time was 2 minutes 4 seconds. DACI laboratory recommends vacuuming for at least 2 minutes. The reservoi r dust analysis Â“Instr uctions for UseÂ” is located in Appendix B. The DACI laboratory ri sk range characterization for allergens is provided in Table 10.
27 Table 10: DACI Risk Range Allergen Low Medium High Der p I < 400 ng/g 400 Â– 2000 ng/g > 2000 ng/g Der f I < 400 ng/g 400 Â– 2000 ng/g >2000 ng/g Fel d I < 8000 ng/g 8000 Â– 80000 ng/g > 80000 ng/g Der f I results ranged from 704 ng/g on February 12, 2008 to 6,720 ng/g on July 7, 2008. Der p I results ranged from 3,408 ng/g on February 12, 2008 to 86,704 on April 14, 2008. Sample results for Fel d I ranged from 2,206 ng/g on March 7, 2008 to 10,558 ng/g on June 3, 2008. The risk range for cockroach alle rgen has currently been established and therefore the DACI laboratory considers any positive results to be significant. All Bla g I samples were below the detection limit thr oughout the study and therefore do not present a significant risk for sensitization or sy mptoms. Tables 11 and 12 provide the DACI laboratory risk range characterization of the reservoir dust sample results. Table 11: DACI Risk Range for Sample Results November, 2007 March, 2008 Sample Date 11/30/07 01/14/08 02/12/08 03/07/08 Allergen ng/g DACIng/g DACIng/g DACI ng/g DACI Der p I 5239 High 16889High 3408 High 4438 High Der f I 2651 High 5951 High 704 Moderate 1574 Moderate Fel d I 3924 Low 7858 Low 3086 Low 2206 Low Bla g I <0.7 U/g <0.4 U/g <0.4 U/g <0.4 U/g Table 12: DACI Risk Range for Sample Results April, 2008 July, 2008 Sample Date 04/14/08 05/05/08 06/03/08 07/07/08 Allergen ng/g DACI ng/g DACI ng/g DACI ng/g DACI Der p I 86704 High 30656 High 15232High 26186High Der f I 6253 High 2718 High 2735 High 6720 High Fel d I 4135 Low 3856 Low 10558Moderate 5797 Low Bla g I <0.4 U/g <0.4 U/g <0.4 U/g <0.4 U/g Laboratory analytical results are found in Appendix C.
28 DISCUSSION AND CONCLUSIONS The purpose of this research was to charac terize kindergarten childrenÂ’sÂ’ exposures to Fel d I, Der p I, Der f I, and Bla g I allergens in carpeting and to quantify classroom time spent on the floor. The literature rega rding the characteristics of the most commonly reported agents that are associated with allergic responses to carpeting are cat, dust mite, and cockroach antigens. The review indicated that there is strong evidence that continuous exposure to high ri sk levels of allergens plays a role in symptoms and sensitization. The review also indicated there is lit tle literature on the duration of exposure to allerg ens and the locations of expos ures within a classroom. This study sought to quantify the con centrations of cat, dust mite, and cockroach allergens in car peting and document and quan tify classroom activities which are floor-based. Over the course of a calendar school year the concentrations of cat, dust mite, and cockroach allergens were measured within reservoir dust samples. Additionally, classroom observa tions were performed to identify the location of group floor-based activities, the number of students, the duration of time students spent in the group floor-based activities, a nd the activities stude nts performed while in groups on the floor. The interior of the classroom and building design was described to put in relation to where the group floor based activities occurred compared to the rest of the classroom ac tivities and how custodial cleaning activities were performed throughout the school year This information is necessary to
29 understand the potential for rese rvoir dust accumulation and th e efficiency of allergen removal associated with the cleaning method. The research did have limitations The study design focused on one elementary school and one kindergarten clas sroom. Only the location of group floorbased activities was targeted to be sample d for reservoir dust sa mples, however, other floor activities did occur throughout the classr oom in individual cen ters. Actual time spent in group floor-based ac tivities varied from the sc heduled curriculum plan throughout the school year because of substitu te teachers with different curriculum plans, special holiday programs, such as ValentineÂ’s Day, FCAT, and other classroom presentations by outside school district personnel. Other vari ables include, the age of the school, school floor pl an, and age of carpeting. Discussion The analytical results of this study were consistent with ot her reported studies. Tranter (2005) reviewed forty-one papers on indoor allergens in settled school dust and reported the findings and significant factor s. The statistical data reported within the D.C. Tranter review included the ge ometric mean, arithmetic mean, and the median from the compilation of papers. The cat allergen concentrations were higher (2,206-10,558 ng/g) than the re ported other studies (8-6 ,000 ng/g). Tranter (2005) reported the geometric mean of cat allergen within the United States from eighteen school studies as 6,000 ng/g, while the arithm etic mean from Table 9 was 5,178 ng/g. Dust mites concentrations were simila r (704-86,704 ng/g) among the other reviewed studies by Tranter (42-50,900 ng/g). The arithm etic mean from a Florida school study for Der p I was three times lower than Table 9 results (23,594 ng/g), while the Tranter
30 (2005) literature reported an arithmetic mean for Der f I as 3,457 ng/g which was comparable to Table 9 results of 3,663 ng/ g. There were no measurable level of cockroach allergens in this study, however, the geometric mean reported from a North Carolina school was 4,600 ng/g. One aspect wh ich made the research presented here unique was the complete assessment of the classroom for an entire calendar school year. Another important aspect of this st udy was the quantification of exposure to the carpeting in a specific higher risk class. The group floor area measurements for Der p I and Der f I ranged from 704 ng/g to 86,704 ng/g. Dust mites are associated with seasonal changes. The sample results on January 14, 2008 and April 14, 2008 were 16,889 ng/g and 86,704 ng/g, respectively, were above the expected concentrations compared to the other surrounding monthÂ’s measurements A number of variables, such as the time of year samples were collected, temperature of the classroom, relative humidity of the classroom, and custodial maintenance of th e classroom, may have contributed to the wide range of concentrations of dust mites and inconsiste ncy of measurements each month. Low to moderate levels of Fel d I concentrations were measured within the classroom, 2,206-10,558 ng/g. Since there are no cats in the classroom the measurement levels are a dire ct result of transference by the occupants. The students of the classroom were not interviewed, so the number of pet owners is unknown. All Bla g I measurements were below detection limits of 0.4 U/g and 0.7 U/g. Although students were observed to eat in the classroom, sanitary practices within the classroom appeared to have been adequate.
31 Measurable concentration levels we re compared to the DACI laboratory criteria for potential risk exposures among at opic or sensitized i ndividuals from home studies. These values are also referred to as Â‘exposure risks,Â’ Â‘levels of concern,Â’ provisional standards,Â’ and Â‘symptom/sens itization levelsÂ’ (Tranter 2005). However, the DACI criteria provide a good benchmark for comparison of concentrations and risk. The total amount of time students spent daily in their classroom was between 253 and 273 minutes. Of this, 95 to 103 minu tes was spent in group floor based activities. The observations of the classroom group floor based activities revealed that the curriculum plan was more of a guide line and depending on the day, other school activities, and the time of year actual time spent on the floor varied. The total number of students enrolled in th e class was 19. During the group floor based activities, up to 19 students participated in curriculum activ ities, which ranged from sitting, standing, walking in place, jogging in place, and reading quietly on the floor. Depending on the activity, student participation provided differe nt levels of carpet disturbances which may allow for varying levels of allergens to become aerosolized. While, there is no direct method for analyzing the actual inhale d concentration of aeroallergens there is evidence that dose-re sponse relationships occur with higher levels of allergens present in settled dust reservoirs. The building heating, ventilation, and air conditioning system was manually controlled by the teachers, and on nice days, classroom doors would be left open. The building design also allowed for people to enter each classroom from an exterior door. The exterior entrance went directly on to the carpeting and in order to cross the
32 classroom, visitors, students, etc. had to cross through the group floor area of the carpeting. This allowed for moisture on shoes, dirt, and debris to be tracked into the room and into the carpeting. In addition, th e carpet was approximately 18 years old, which has resulted in the carpeting beco ming more compact over time and has more of a likelihood of higher accumulation of allergens. Conclusions Kindergarten children spent approximat ely 38% of their classroom day in floor based group activities. The students we re observed perfor ming activities during the time spent on the carpet, which resulted in varying levels of carpet disturbance. Classroom observations identified differen ces in the planned curriculum and actual time spent on the floor. Therefore, the planned curriculum timeline was used to provide the exposure durati on to allergens during the group floor activities. The conclusion can be drawn, however, that in a kindergarten classroom floor-based activities play an important role in the curriculum teaching for the children. The group floor area measurements in cluded moderate to high levels of Der p I and Der f I, low to moderate levels of Fel d I, and below detection limits of Bla g I Concentrations of the allergens meas ured ranged from 2,206 ng/g Â– 10,558 ng/g Felis domesticus I, 3,408 ng/g Â– 86,704 ng/g Dermatophagoides pteronyssinus I, 704 ng/g Â– 6,720 ng/g, Dermatophagoides farinae I, and below detection limits for Bla g I, respectively. The concentration measurem ents varied from month to month and therefore, were not consistent throughout the study. Based upon the DACI criteria for risk range, high allergen concentrations ( Der p I 86,704 ng/g and Fel d I 10,558 ng/g) were recorded in between m onths with concentrations of 3 to 19 times lower. The
33 analytical results suggest that there are signi ficant levels of allergens in the carpeting and many variables play an important ro le in the concentrations. Based upon the DACI laboratory criteria there is a moderate to high risk of incr eased sensitization or allergic symptoms as a result of the repeat ed and continued exposure to the carpeting. Recommendations for Future Research Based on the findings from this study, the following recommendations for future research are provided. These include: Expand the study and select more kinderg arten classrooms with different age carpeting to better characterize concentration levels. Conduct a cross-sectional ep idemiological study that us es surveys designed to measure current health problems of occ upants and reservoir dust sampling to assess exposure. Develop sampling protocol for airborne measurements for Der p 1, Der f 1, Fel d 1, and Bla g This will provide a better understanding of exposure risk and dose-response.
34 References Cited ALA (2008). "Childhood Asthma Over view." Retrieved December, 2008. Causer, S., R. D. Lewis, et al. (2004). "Influence of Wear Pile Height, and Cleaning Method on Removal of Mite Allergen from Carpet." Journal of Occupational and Environmental Hygiene 1 : 237-242. Causer, S., C. Shorter, et al. (2006). "Effect of Floorcove ring Construction on Content and Vertical Distribution of house Dust Mite Allergen, Der p 1." Journal of Occupational and Environmental Hygiene 3 : 161-168. Corsi, R. L., J. A. Siegel, et al. (2008). "P article Resuspension During the Use of Vacuum Cleaners on Residential Carpet." Journal of Occupational and Environmental Hygiene 5 (4): 232-238. Elliott, L., S. J. Arbes Jr., et al. (2007). "Dust Weight and Asthma Prevalence in the National Survey of Lead and Allergens in Housing (NSLAH)." Environmental Health Perspectives 115 (2): 215-220. FLDOE (2008). "Accountability, Research, and Measurement." Retrieved December, 2008. German, J. A. and M. B. Harper (2002). "E nvironmental Control of Allergic Diseases." American Family Physician 66 (3): 421-426. Gold, D. R. (2000). "Environmental Tobacco Smoke, Indoor Allergens, and Childhood Asthma." Environmental Health Perspectives 104 (4): 643-651. Hamilton, R. G. (2005). "Assessment of Indoor Allergen Exposure." Current Allergy and Asthma Reports 5 : 394-401. Hamilton, R. G., M. D. Chapman, et al. (1992) "House Dust Aeroallergen Measurements in Clinical Practice: A Guide to Allergen-F ree Home and Work Environments." Journal of Immunology and Allergy Practice 14 (3): 9-25. IOM (1993). Magnitude and dimensions of sensitization and disease cause by indoor allergens; Agents, sources, source controls, and diseases; Engineer ing control strategies Indoor Allergens, Washington D.C., Institute of Medicine.
35 IOM (2002). Indoor biologic exposures. In Clearing the Air: Asthma and Indoor Air Exposures, Washington D.C., Institute of Medicine. Macher, J., H. Ammann, et al. (1999). Bioaerosols Assessment and Control Cincinnati, American Conference of Govern mental Industrial Hygienist. Macher, J., F. Tsai, et al. (2002). Concentrations of cat and dust mite allergens in 93 U.S. office buildings Indoor Air Conference, Monterey, CA International Academy of Indoor Air Sciences. Platts-Mills, T. A. E., R. B. Sporik, et al. (1995). "Is there a do se-response relationship between exposure to indoor al lergens and symptoms of asth ma?" The Journal of Allergy and Clinical Immunology 96 (4): 435-439. Ramachandran, G., J. L. Adgate, et al. (2005). "Indoor Air Quality in Two Urban Elementary Schools Measurements of Ai rborne Fungi, Carpet Allergens, CO2, Temperature, and Relative Humidity." J ournal of Occupationa l and Environmental Hygiene 2 (553-566): 553. Tovey, E. and G. Marks (1999). "Methods and Effectiveness of Envi ronmental Control." Journal of Allergy a nd Clinical Immunology 103 (2 pt 1): 179-191. Tranter, D. C. (2005). "Indoor allergens in settled school dust: a review of findings and significant factors Clinical and Experimental Allergy 35 : 126-136. USEPA (2008). "Indoor Air Qualit y." Retrieved December, 2008.
37 Appendix A: Sample Information Location/Site Elementary School/Group Floor Area Method DACI Dust Analysis Equipment Numatic International Vacuum Cleaner, RSV 130, Serial #044613259 Sample ID R1623 R2172 R2602 R3005 Sample Date 11/30/07 01/ 14/08 02/12/08 03/07/08 Sample Time 2:45 PM 3:00 PM 2:45 PM 2:45 PM Classroom Occupancy 19 19 18 19 Sample Duration 2 mn 5 sec 2 mn 7 sec 1 mn 56 sec 2 mn 8 sec Location/Site Elementary School/Group Floor Area Method DACI Dust Analysis Equipment Numatic International Vacuum Cleaner, RSV 130, Serial #044613259 Sample ID R3419 R3735 R4011 R4446 Sample Date 04/14/08 05/ 05/08 06/03/08 07/07/08 Sample Time 3:24 PM 3:04 PM 1:30 PM 11:40 AM Classroom Occupancy 15 18 18 0 Sample Duration 2 mn 1 sec 2 mn 7 sec 2 mn 5 sec 2 mn 18 sec
38 Appendix B: DACI Laboratory Instruction for Use
39 Appendix B (Continued)
40 Appendix C: Analytical Laboratory Results
41 Appendix C (Continued)
42 Appendix C (Continued)
43 Appendix C (Continued)
44 Appendix C (Continued)
45 Appendix C (Continued)
46 Appendix C (Continued)
47 Appendix C (Continued)