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Workshop 1: A Practical Approach to Aeroallergen Identification

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1 Workshop 1: A Practical Approach to Aeroallergen Identification
How to Set Up a Sampling Station Estelle Levetin, PhD

2 Learning Objectives and Disclosure Information
Upon completion of this workshop, participants should be able to: Set up a sampling station to collect airborne pollen and fungal spore Recognize the most common types of pollen found in the atmosphere Recognize the most common types of fungal spores found in the atmosphere No conflicts to disclose

3 Aerobiological Sampling
Sampling plan or objective Choosing samplers: Rotorod, Burkard Spore Trap, Lanzoni, Krammer-Collins, Allergenco Location One day head or 7 day head for Burkard Preparing the samples Slide Analysis and Identification Data Analysis

4 Sampling Objective Pollen only or both pollen and spores
Sampling frequency 7 days a week 5 days a week 3 days a week Time commitment

5 Rotorod Samplers

6 Rotorod Samplers Models most often used by allergists have retracting rods for intermittent operation Standard is 10% sampling time Head rotates at 2400 rpm Leading edge of rod coated with grease Pollen and spores impacted on greased surface Efficient for pollen and spores >10 mm

7 Rotorod Samplers

8 Older Model Rotorod Sampler

9 Rotorod Analysis Collector rods placed in a special adapter for microscopic examination Rods stained with Calberla’s pollen stain Entire surface of each rod counted unless pollen/spore load very high (then a subset of the surface is analyzed) Atmospheric concentrations determined

10 Rotorod Calculations C = N / V V = Rod area (m2) x D x p x RPM x t
C is concentration, N is the total number of pollen or spores counted on both rods, V is the volume of air sampled by the rods V = Rod area (m2) x D x p x RPM x t Rod area = width of rod (1.52 mm = m) x length of the rod (23 mm = 0.023m) x 2 (both rods), D is the diameter of the Rotorod head (8.5 cm = 0.085m), RPM is 2400, t is minutes sampled per day With a 5% sampling time (72 min) V = m3 Concentration = N/3.226 m3 With a 10% sampling time (144 min) V = m3 Concentration = N/6.452 m3

11 Hirst Spore Trap Burkard Spore Trap Lanzoni Spore Trap
Kramer-Collins Spore Trap Allergenco

12 Burkard Spore Trap

13 Lanzoni VPPS Sampler

14 Allergenco – Samplair MK-3

15 Advantages of Burkard Spore Trap
High efficiency down to less than 5 mm Allows for greater accuracy for small fungal spores Time discrimination Permits analysis for diurnal rhythms Permanent slides for future reference

16 Location Roof of a building - ideal 3 to 6 stories above ground (30 to 60 ft) Not close to overhanging vegetation Air flow not obstructed by nearby buildings or other structural features

17 Burkard 7-day sampler head
Standard is the 7-day sampling head Sampler drum mounted on 7-day clock Drum moves by orifice at 2 mm per hr Melenex tape mounted on drum and greased (Lubriseal, High Vacuum Grease, other) Air is brought in at 10 l/min and impacts on greased Melenex tape Drum changed each week

18 Seven Day Sampling Head

19 Processing the 7-day drum
Melenex tape removed from drum Tape cut into seven 24 hour segments each 48 mm long Segments mounted on microscope slides in 10% gelvatol (polyvinyl alcohol) and dried Glycerin-jelly mounting medium added and a 50 mm cover slip Mounting medium contains pollen stain - either basic fuchsin or phenosafarin

20 Melenex tape on cutting board

21 One-day sampling head Alternate head is the 24 hour head
Standard glass microscope slide is greased and placed on the head Alternatively Melenex tape can be fixed on the slide and greased Slide is changed daily, carrier realigned Mounting medium with stain and coverslip are added

22 24 hour sampling head

23 Outdoor air sample from Tulsa

24 Analysis Microscopy - 400X for pollen; 1000X for fungal spores
Different methods of microscopic analysis are used to obtain Average daily concentration - Single longitudinal traverse Hourly or bihourly concentrations which can then be averaged to obtain a daily average - 12 transverse traverses


26 Comparison of methods Single Longitudinal Traverse
Quicker Produces average daily concentration Good for routine monitoring 3 or 4 longitudinal traverses can increase accuracy 12 Transverse Traverses Takes longer Can determine diurnal rhythm of airborne allergens All traverses can be averaged to determine average daily concentration

27 Conversion to Concentrations
Microscope counts are entered into a database such as Excel Formulas added to convert counts into concentrations Information needed Field diameter of objective lens - Variable Flow rate (10 liters/minute) and exposure time (normally 24 hrs) for a total volume of air sampled of 14.4 m3

28 Calculating Concentrations for Single Longitudinal Traverse
C = Concentration - pollen grains/m3 N = number of pollen counted on traverse W = Width of entire sample - 14 mm F = field diameter of objective lens mm V = total volume of air sampled m3 C = N x W/F x 1/V C = N x 14mm/0.48mm x 1/14.4m3 C = N x 2.025

29 Example of an Excel Spreadsheet with 15 Days of Pollen Data

30 Identification AAAAI and ACAAI Aeroallergen courses
Other aerobiology courses Reference slides NAB/AAAAI Pollen Slide Library Reference slides from local specimens Consult a botanist at a local university Identification Manuals

31 Identification Manuals
Grant Smith Sampling and Identifying Allergenic Pollens and Molds, AAAAI, Milwaukee R.O. Kapp, How to Know Pollen and Spores - originally published in 1950s - new edition Richard Weber Pollen Identification Ann Allergy Asthma Immunol 80:141–7. Lewis WH, Vinay P, Zenger VE Airborne and Allergenic Pollen of North America. Johns Hopkins University Press, Baltimore, MD. Aeroallergen Photo Library, Steve Kagan,

32 Essential Reference Grant Smith’s Sampling and Identifying Allergenic Pollen and Molds

33 Sample Pages


35 How the data can be used Average daily concentrations can be graphed to look at the seasonal and yearly pollen levels Develop regional pollen calendar Data can be compared with patient symptoms, peak flow readings, office visits, emergency room visits Prepare for peak seasons - staffing, etc


37 Airborne Ambrosia pollen in Tulsa Fall 1999

38 Multiple Years of Data Data from several years can be averaged to produce a graph of the pollen season Smoothing techniques such as 5 day running mean can be used to generate a smoother curve and better estimate of the typical peak period

39 Airborne Ambrosia pollen in Tulsa: 20 year mean

40 Five day running mean of airborne Ambrosia pollen in Tulsa: 20 year mean
Peak on or about Sept 10

41 Conclusion Air sampling allows the allergist to get a first hand understanding of the local aeroallergens, their concentration, and season occurrence Several years of sampling will allow for the development of a pollen calendar which can benefit the physician and his or her patients

42 Additional references
Gregory, P. H The Microbiology of the Atmosphere, 2nd ed., Halstead Press, NY. Lacey, J and J. Venette Outdoor Air Sampling Techniques. in Bioaerosols Handbook, C.S. Cox and C.M.Wathes, ed., Lewis Publishers, Boca Raton, FL. Levetin E. and Horner WE. Fungal Aerobiology: Exposure and Measurement, in “Fungal Allergy and Pathogenicity”, ed by Brittenbach, Crameri, Lehrer. Krager, Basel. 2002; 81: Weber, R (ed) Immunology and Allergy Clinics of North America. Vol 23 (3) Aerobiology

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