%0 Journal Article %J Atmospheric Science %D 1983 %T Testing of the Air Resources Laboratories Trajectory Model on Cases of Pollen Wet Deposition After Long-distance Transport from Known Source Regions %A Raynor, G. S. %A Hayes, J. V. %A Lewis, D. M. %K biology %X
A version of the Air Resources Laboratories Atmospheric Transport and Dispersion Model was tested to determine how well it could identify probable pathways and source regions of airborne pollens from non-local sources which were deposited in precipitation at Albany, New York. The model calculates either forward or backward trajectories from any selected location starting every 6-h during a chosen time period. Each trajectory is calculated using transport winds averaged over a selected vertical layer and is based on past upper air observations stored in the computer.
At Albany, New York, airborne pollens were sampled during both wet and dry weather. Samples were examined under a microscope and pollen grains identified and counted. In this study, only obviously fresh pollens of non-local origin are considered. These were obtained primarily in the winter and early spring months before local pollens of the same or similar species were released and include species whose ranges do not reach the north-eastern states. These cases document atmospheric transport from distant source regions and subsequent wet deposition.
Probable source regions were determined from ranges and flowering dates of the taxa collected. Backward trajectories from Albany were computed for nine precipitation events. In all cases, the trajectories passed through or very near previously identified source regions located to the south or south-west. Travel times ranged from 10 to over 50 h but were mostly from 18 to 42 h. Results demonstrate the utility of the model and the feasibility of locating source regions of materials transported over long distances.
%B Atmospheric Science %V 17 %P 213-220 %G eng %U http://www.sciencedirect.com/science/article/pii/0004698183900355 %R 10.1016/0004-6981(83)90035-5 %0 Journal Article %J Rhodora %D 1976 %T Dispersion of Fern Spores Into and Within A Forest %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %B Rhodora %V 78 %P 473487 %G eng %0 Journal Article %J Annals of Allergy %D 1976 %T Temporal Variability in Airborne Pollen Concentrations %A Raynor, G. S. %A Hayes, J. V. %A Ogden, E. C. %K biology %B Annals of Allergy %V 36 %P 386-396 %G eng %0 Journal Article %J Boundary-Layer Meteorology %D 1975 %T Particulate Dispersion from Sources within a Forest %A Raynor, G. S. %A Hayes, J. V. %A Ogden, E. C. %K biology %X

Particulate dispersion from sources within a 10- to 13-m tall pine forest was studied experimentally at Brookhaven National Laboratory using stained ragweed pollen and other tracers ranging from 14 to 58 Μm in size. Forty-seven continuous point source releases lasting from 22 to 55 min were made at heights from 1.75 to 14.0 m from locations having a long fetch through the forest. In most experiments, differently colored ragweed pollen were emitted simultaneously from three locations. In other tests, several particle types were released from a single point. The sampling network consisted of 119 rotoslide samplers at heights from 0.5 to 21.0 m at 57 positions within and at the edge of the forest. Deposition to the ground was sampled by greased microscope slides at each position. Meteorological measurements were taken in and near the forest.

Data were classified by particle characteristics, source height and meteorological parameters. Concentration patterns were illustrated on scale diagrams of the sampling grid. Changes in centerline and crosswind integrated concentrations, plume width and height, mass flux, deposition and deposition velocity were studied as a function of distance, particle size and wind speed. Results were compared to those obtained from similar releases over open terrain.

In the forest, vertical predominates over lateral dispersion and considerable interchange occurs through the canopy. Flow is channelled somewhat by vegetation density differences but is generally in the direction of the mean wind above the forest. No systematic turning of the wind with height was observed. Most particles are lost to the foliage rather than to the ground and large particles are lost more rapidly than smaller ones. Rate of change in mass flux is similar to that over open terrain and is greater with light than with stronger wind speeds.

%B Boundary-Layer Meteorology %V 9 %P 257-277 %G eng %U http://link.springer.com/article/10.1007/BF00230770 %R 10.1007/BF00230770 %0 Journal Article %J Journal of Allergy and Clinical Immunology %D 1975 %T Spatial Variability in Airborne Pollen Concentrations %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X
Tests were conducted to determine the relationship between airborne pollen concentrations and distance. Simultaneous samples were taken in 171 tests with sets of eight rotoslide samplers spaced from one to 486 M. apart in straight lines. Use of all possible pairs gave 28 separation distances. Tests were conducted over a 2-year period in urban and rural locations distant from major pollen sources during both tree and ragweed pollen seasons. Samples were taken at a height of 1.5 M. during 5-to 20-minute periods. Tests were grouped by pollen type, location, year, and direction of the wind relative to the line. Data were analyzed to evaluate variability without regard to sampler spacing and variability as a function of separation distance. The mean, standard deviation, coefficient of variation, ratio of maximum to the mean, and ratio of minimum to the mean were calculated for each test, each group of tests, and all cases. The average coefficient of variation is 0.21, the maximum over the mean, 1.39 and the minimum over the mean, 0.69. No relationship was found with experimental conditions. Samples taken at the minimum separation distance had a mean difference of 18 per cent. Differences between pairs of samples increased with distance in 10 of 13 groups. These results suggest that airborne pollens are not always well mixed in the lower atmosphere and that a sample becomes less representative with increasing distance from the sampling location.
%B Journal of Allergy and Clinical Immunology %V 55 %P 1975 %G eng %U http://www.sciencedirect.com/science/article/pii/0091674975900160 %0 Journal Article %J Agricultural Meteorology %D 1974 %T Enhancement of Particle Concentrations Downwind of Vegetative Barriers %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X
A series of experiments was conducted to study the effect of hedgerows on airborne pollen concentrations. Sampling of tree pollens and ragweed pollen from distant upwind sources was conducted with rotoslide samplers mounted at three heights and sixteen locations both upwind and downwind of a dense arbor-vitae hedge and a porous deciduous hedge. A pronounced concentration maximum was found in the cavity region downwind of each hedge.
%B Agricultural Meteorology %V 13 %P 181-188 %G eng %U http://www.sciencedirect.com/science/article/pii/0002157174900454 %R 10.1016/0002-1571(74)90045-4 %0 Journal Article %J Journal of Applied Meteorology %D 1974 %T Mesoscale Transport and Dispersion of Airborne Pollens %A Raynor, G. S. %A Hanes, J. V. %A Ogden, E. C. %K biology %X

Pollen transport and dispersion from generalized area sources was studied by 29 flights to distances of 100 km and heights of 3 km using an aircraft-mounted isokinetic sampler. Tree pollens and ragweed pollen served as tracers. Four types of flights were made to study various aspects of pollen transport: 1) ascents over a fixed location to investigate vertical distribution; 2) flights over a source-free area to document change of concentration with distance, 3) east-west flights along Long Island to study the influx of pollen from the mainland with westerly winds; and 4) vertical ascents and horizontal flights during sea breeze flows to determine their effect on pollen concentrations.

It was found that large quantities of pollen are transported in orderly fashion from their source regions but pollen often travels in large, discrete clouds. Pollen is transported to Long Island from the mainland in some quantity. Sea breeze flows greatly decrease low-level concentrations but pollen is carried aloft at the sea breeze front and recirculated in the return flow aloft. Vertical distribution is reasonably well related to lapse rate although secondary concentration peaks which often occur below elevated inversions cannot be explained by the data obtained.

%B Journal of Applied Meteorology %V 13 %P 87-95 %G eng %U http://journals.ametsoc.org/doi/abs/10.1175/1520-0450%281974%29013%3C0087:MTADOA%3E2.0.CO;2 %R http://dx.doi.org/10.1175/1520-0450(1974)013<0087:MTADOA>2.0.CO;2 %0 Journal Article %J Boundary-Layer Meteorology %D 1974 %T Particulate Dispersion Into and Within a Forest %A Raynor, G. S. %A Hayes, J. V. %A Ogden, E. C. %K biology %X

Particulate dispersion into and within a 10- to 13-m tall pine forest was studied experimentally at Brookhaven National Laboratory using stained ragweed pollen and other tracers ranging from 14 to 54 Μm in diam. Seventy-two continuous point source releases lasting 20 to 40 min were made at various distances from within the forest edge to 60 m upwind and at heights of 1.75 to 14.0 m. In most experiments, differently colored ragweed pollen was released simultaneously from three locations. Thirty-six longer tests were made using pollen from area sources of ragweed and three with pollen from distant sources. All tests were made during the day with steady winds and unstable lapse rates outside the forest. The sampling network consisted of 119 rotoslide samplers mounted at heights from 0.5 to 21.0 m at 57 positions extending 100 m into the forest. Deposition was sampled by greased microscope slides at each sampling position. Meteorological measurements were taken in and near the forest.

Data were classified by particle characteristics; by source type, distance and height; and by meteorological parameters. Isopleths were drawn on scale diagrams of the sampling grid to illustrate concentration patterns. Changes in centerline concentration, crosswind integrated concentration, mass flux, plume width, plume height, deposition, and deposition velocity were related to distance within the forest and other variables. Results were compared to those of similar releases over open terrain and those of previous forest dispersion studies elsewhere.

The plume approaching the forest is broadened both vertically and horizontally by increased turbulence at the forest edge and flows mainly into the trunk space and above the forest. Lateral spread is slow within the forest, but vertical spreading beyond the entrance region is greater than in the open. Particles become mixed uniformly below the canopy while appreciable interchange takes place through this layer. Concentration within the forest decreases at a faster rate than in the open, but change in total mass flux within and above the forest is not significantly different. Loss of material takes place by impaction near the forest edge and in the tree tops and by deposition within the forest. Most loss takes place to the foliage rather than the ground, and larger particles are lost faster than smaller ones.

%B Boundary-Layer Meteorology %V 7 %P 429-456 %G eng %U http://link.springer.com/article/10.1007/BF00568335 %R 10.1007/BF00568335 %0 Journal Article %J Agricultural Meteorology %D 1973 %T Dispersion of Pollens from Low-Level, Crosswind Line Sources %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X
Dispersion and deposition of pollens emitted naturally from 80-m long, crosswind, line sources of living plants and of pollens sprayed from a moving vehicle were studied in a set of 45 experiments at Brookhaven National Laboratory. Concentrations were measured by 276 wind-impaction samplers mounted in a square array which included four heights at each of 69 positions. Deposition was measured by greased microscope slides on the ground. Data are presented as functions of distance from the source, pollen type and release height for decrease in concentration, plume height, mass flux, deposition and deposition velocity. Results are compared with those from previous point and area source dispersion experiments. Values computed from a multi-point source, Gaussian-plume diffusion model gave reasonably good agreement with the experimental measurements.
%B Agricultural Meteorology %V 11 %P 177-195 %G eng %U http://www.sciencedirect.com/science/article/pii/0002157173900629 %R 10.1016/0002-1571(73)90062-9 %0 Journal Article %J Journal Allergy and Clinical Immunology %D 1973 %T Variation in Ragweed Pollen Concentration to a Height of 108 Meters %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X
Ragweed pollen concentrations were measured at 5 levels from 1.5 to 108 M. on a meteorology tower at Brookhaven National Laboratory. Samples were taken over an 11 year period using both the rotoslide and the slide-edge cylinder samplers. Vertical pollen profiles showed great variability from day to day but, when averaged over pollen seasons or longer periods, little systematic change in height was found. These results suggest that long-term patient exposure at upper levels of tall buildings would be similar to that at ground level in the absence of nearby pollen sources.
%B Journal Allergy and Clinical Immunology %V 51 %P 199-207 %G eng %U http://www.sciencedirect.com/science/article/pii/0091674973901395 %R 10.1016/0091-6749(73)90139-5 %0 Journal Article %J Agronomy Journal %D 1972 %T Dispersion and Deposition of Corn Pollen from Experimental Sources %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X

The atmospheric dispersion and subsequent deposition of corn (Zea mays L.) pollen emitted from plants in two 18-m diameter plots were studied in 39 tests at Brookhaven National Laboratory to compare the spread of this large pollen to that of smaller pollens studied previously. Concentrations were measured by wind-impaction samplers mounted at four heights (0.5 to 4.6 m) and at five distances from the source on 20-degree radii. Deposition was measured by greased microscope slides on the ground.

Data were analyzed in terms of current meteorological dispersion theory. Normalized centerline concentrations, crosswind integrated concentrations, plume widths and heights, and mass flux are presented as functions of distance and compared to similar data from ragweed (Ambrosia) and timothy (Phleum pratense) sources of comparable size. Normalized centerline and crosswind integrated deposition and velocity of deposition are also presented as functions of distance and are compared to ragweed and timothy pollen data. The study shows that corn pollen is not transported as far by the wind as smaller pollens, does not disperse as widely in either the horizontal or the vertical direction and settles to earth more quickly, much of it within the source itself.

The dispersion of corn pollen is influenced by its large size and rapid settling rate. At 60 m from the source in the downwind direction, concentrations average about 1% of those at 1 m. Width of the pollen plume at 60 m is less than that of smaller pollens under similar conditions. The rate of settling opposes the rate of upward dispersion so that the height of the pollen plume does not increase continuously with downwind distance. At 60 m from the source concentrations integrated in the crosswind direction average from 3 to 6% of those at 1 m. The total amount of pollen remaining airborne at 60 m is 5% of that at 1 m.

Total deposition within the source plot is greater than that outside. Deposition per unit area at 60 m downwind is only 0.2% of that near the source. Crosswind integrated deposition at 60 m varies from 0.5 to 0.8% of that at 1 m. The velocity of deposition at 32 m from the source averages about 33 cm/sec.

%B Agronomy Journal %V 64 %P 420-427 %G eng %U https://dl.sciencesocieties.org/publications/aj/abstracts/64/4/AJ0640040420 %R 10.2134/agronj1972.00021962006400040004x %0 Journal Article %J Agricultural Meterology %D 1972 %T Dispersion and Deposition of Timothy Pollen from Experimental Sources %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X
Dispersion and deposition of timothy pollen emitted naturally from circular area sources 18–37 m in diameter and artificially from point sources were studied in 64 tests at Brookhaven National Laboratory. Concentrations were measured by wind-impaction samplers mounted at four heights (0.5–4.6 m) and five or six distances from the source on 20° radii. Deposition was measured by greased microscope slides on the ground.
Data are analyzed in terms of current dispersion theory. Normalized centerline concentrations, crosswind integrated concentrations, plume widths and heights, mass flux and the size of areas having concentrations above selected values are presented as functions of distance and related to source size and meteorological variables. Deposition data are also related to distance and source size. Most deposition velocities ranged from 10 to 14 cm/sec but many values close to the source were much higher. Loss of airborne particles between sampling circles is compared to deposition over the same distances. Results are compared to previous dispersion and deposition experiments, including a large number of similar ragweed pollen tests, and to theory.
%B Agricultural Meterology %V 9 %P 347-366 %G eng %U http://www.sciencedirect.com/science/article/pii/0002157171900331 %R 10.1016/0002-1571(71)90033-1 %0 Journal Article %J Journal of Applied Meteorology %D 1970 %T Dispersion and Deposition of Ragweed Pollen from Experimental Sources %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X

Dispersion and deposition of ragweed pollen released naturally from circular area sources of four sizes (5–27 m in diameter) and artificially from point sources were studied at Brookhaven National Laboratory. Concentrations were measured by wind-impaction samplers mounted on 20° radii at four heights (0.5–4.6 in) and four or five distances from the sources to a maximum of 69 m. Deposition was measured by greased microscope slides on the ground. Differences in dispersion patterns between point and area sources are analyzed. Normalized centerline concentrations, cross-wind integrated concentrations, plume widths, plume heights and mass flux are presented as functions of distance and related to source size and meteorological variables. Deposition data are also related to distance and source size. Most deposition velocities ranged from 2–6 cm sec−1 but values close to area sources were much greater. Loss of airborne particles between sampling circles is compared to deposition over the same distances. Results are compared to those of previous dispersion and deposition studies and to theory.

%B Journal of Applied Meteorology %V 9 %P 885-895 %G eng %U http://journals.ametsoc.org/doi/abs/10.1175/1520-0450%281970%29009%3C0885:DADORP%3E2.0.CO%3B2 %R 10.1175/1520-0450(1970)009<0885:DADORP>2.0.CO;2 %0 Book %D 1970 %T Experimental Data on Dispersion of Timothy and Corn Pollen from Known Sources %A Raynor, G. S. %A Hayes, J. V. %A Ogden, E. C. %K biology %I Brookhaven National Laboratory %C New York %G eng %0 Journal Article %J Journal of Allergy %D 1968 %T Effect of a Local Source on Ragweed Pollen Concentrations from Background Sources %A Raynor, G. S. %A Ogden, E. C. %A Hayes, J. V. %K biology %X

Dispersion of pollen from local ragweed sources was studied to determine the effect of contributions from such sources upon the pollen concentrations originating in more distant areas. Since ragweed pollen is produced throughout a large region, concentrations measured at any given location represent contributions from many sources at various distances along the past trajectory of the air sampled. A local source may produce concentrations several orders of magnitude above this background in a small downwind region. These concentrations decrease with distance and at some point become insignificant in comparison to background concentrations. Five experimental plots of common ragweed (Ambrosia artemisiifolia) were grown at Brookhaven National Laboratory over a four-year period. Pollen concentrations were measured by arrays of samplers located in concentric rings at several distances from each source. These concentrations were studied in relation to background pollen. The maximum downwind concentration is related to source size. Distances necessary for concentrations to reach specified fractions of background and the areas covered by concentrations greater than specified multiples of background are related to source size, surrounding vegetation, and meteorological conditions. These data should provide guidance to allergists and public health officials in evaluating the importance of local sources.

%B Journal of Allergy %V 41 %P 217-225 %G eng %U http://www.jacionline.org/article/0021-8707%2868%2990044-0/abstract %R 10.1016/0021-8707(68)90044-0