POLLEN ALLERGY IN THE BILBAO AREA (EUROPEAN ATLANTIC SEABOARD CLIMATE) - POLLINATION FORECASTING METHODS

Forecasting pollination can help the allergist to establish the approp riate treatment and advice for patients. Based on previous studies, we have related the climate variables with the grass pollen counts in th e search for pollination predictors. By relating the meteorological da ta of the temperature recorded every 6 h and of the rainfall in hourly periods, together with the daily pollen counts obtained by the Hirst volumetric system, over a period of 3 years, we have tried to predict the start, duration and severity of the grass pollination, as well as the days of peak pollination. We have established a relationship by me ans of a polynomic regression originating from the mean cumulated temp erature higher than 9 degrees C [R(2) = 0.927 (P = 0.0001)], with the pollination season starting from 300 degrees C and the maximum peak at 356 degrees C, in the 3 years of the study. During the days of pollin ation, peaks higher than 50 grains/m(3) coincide with average daily te mperatures of 18.7 +/- 3 and lower than 50 grains/m(3) with temperatur es of 16.8 +/- 3 (significant to 95%). The duration of the pollination is influenced by the cumulated average temperatures (from 800 to 900 degrees C) and especially by precipitation at the start of and during pollination. In order to forecast grass pollination, the cumulated ave rage temperatures are useful, starting from a basal(9 degrees C), poll ination begins when this sum is greater than 300 degrees C, whereas wh en 800 degrees C is reached and depending on the rainfall during the s eason, pollination will end. The total severity of pollination seems t o depend on the rainfall prior (in the same year) to the start. During pollination, the days with an average temperature of 18.7 +/- 3 degre es C and an absence of rainfall between 4 and 12 h, will be the days w ith a presence of more than 50 grains/m(3). Thus, it is possible to fo recast and estimate risk factors in the long-term (by means of the rai nfall prior to pollination) and in the short-term (for the following d ay, if a weather forecast is available) so as to offer it to those mem bers of the population affected by pollinosis.