Search

To describe the season of airborne pollen ofbirch and grass in the city of Nuuk, Greenland,pollen concentrations were measured dailythroughout the pollen seasons in 1997 to 1999.The study was part of a large epidemiologicalcross-sectional study of allergy and riskfactors for allergy in Greenlander Inuit livingin Greenland and Denmark.For the three years the mean birch pollenseason started around 8 June, lasted in average16 days and the mean annual total pollen countwas 46. The highest daily concentration of 23birch pollen pr. m3 was measured in 1999.The mean grass pollen season began around 22July, it lasted 53 days and the mean annualtotal pollen count was 81. The highest grasspollen number registered for one day reached 12in 1998. Several other types of pollen werealso measured, generally in smallconcentrations, but for Cyperaceae and Alderthe mean annual total pollen count were 43 and19 respectively. Though the measuredconcentrations are small, it is concluded thatairborne pollen occur in the arctic climate ofNuuk in potentially clinically relevantamounts.For the three years large variations wereobserved for the start, duration and amountsfor both birch and grass. Models forestimation of the starting date based onGrowing Degree Hours (GDHs) predicted the startof the birch and grass pollen with greataccuracy – within one day. Analysis of themeteorological conditions show that themeasured pollen in general originated from thearea around Nuuk, but there are indicationsthat pollen might have been long-transportedfrom Canada. [ABSTRACT FROM AUTHOR]

During the last two decades the climate inDenmark has become warmer and in climatescenarios (IPCC, 2001) it is foreseen that thetemperature will increase in the comingdecades. This predicted future increase intemperature will probably affect both theflowering of plants and the dispersion ofpollen in the air. In this study the alreadyobserved effects on the birch pollen season arestudied.Trend analyses of the birch pollen seasonfor two stations in Denmark more than 200 kmapart give similar results. In Copenhagen thereis a marked shift to an earlier season – itstarts about 14 days earlier in year 2000 thanin 1977, the peak-date is 17 days earlier andthe season-end is 9 days earlier. For Viborgthe trend to an earlier season is in generalthe same, but slightly smaller.During the same period there has also beena distinct rise in the annual-total amount ofbirch pollen, peak-values and days withconcentrations above zero.Rising mean temperatures during winter andspring can explain the calculated trends towardearlier pollen season. Models for estimation ofthe starting date based on Growing Degree Hours(GDH's) give very fine results with acorrelation coefficient around 0.90 and rmserror around 4.2 days.For annual-total there is a significantpositive correlation with the mean temperaturein the growing season the previous year. [ABSTRACT FROM AUTHOR]

The last decade progress in numerical weather prediction (NWP) modelling and studies of urban atmospheric processes for providing meteorological data for urban air pollution forecasting is analysed on examples of several European meteorological centres. Modern nested NWP models are utilising land-use databases down to 1 km resolution or finer, and are approaching the necessary horizontal and vertical resolution suitable for city scale. The recent scientific developments in the field of urban atmospheric physics and the growing availability of high-resolution urban surface characteristics data promise further improvements of the capability of NWP models for this aim. A strategy to improve NWP data for the urban air pollution forecasting is suggested. [ABSTRACT FROM AUTHOR]