Jean Emberlin

Air Pollution Pollens, and Daily Admissions for Asthma in London 1987-92

BACKGROUND A study was undertaken to investigate the relationship between daily hospital admissions for asthma and air pollution in London in 1987–92 and the possible confounding and modifying effects of airborne pollen. METHODS For all ages together and the age groups 0–14, 15–64 and 65+ years, Poisson regression was used to estimate the relative risk of daily asthma admissions associated with changes in ozone, sulphur dioxide, nitrogen dioxide and particles (black smoke), controlling for time trends, seasonal factors, calendar effects, influenza epidemics, temperature, humidity, and autocorrelation. Independent effects of individual pollutants and interactions with aeroallergens were explored using two pollutant models and models including pollen counts (grass, oak and birch). RESULTS In all-year analyses ozone was significantly associated with admissions in the 15–64 age group (10 ppb eight hour ozone, 3.93% increase), nitrogen dioxide in the 0–14 and 65+ age groups (10 ppb 24 hour nitrogen dioxide, 1.25% and 2.96%, respectively), sulphur dioxide in the 0–14 age group (10 μg/m3 24 hour sulphur dioxide, 1.64%), and black smoke in the 65+ age group (10 μg/m3 black smoke, 5.60%). Significant seasonal differences were observed for ozone in the 0–14 and 15–64 age groups, and in the 0–14 age group there were negative associations with ozone in the cool season. In general, cumulative lags of up to three days tended to show stronger and more significant effects than single day lags. In two-pollutant models these associations were most robust for ozone and least for nitrogen dioxide. There was no evidence that the associations with air pollutants were due to confounding by any of the pollens, and little evidence of an interaction between pollens and pollution except for synergism of sulphur dioxide and grass pollen in children (p<0.01). CONCLUSIONS Ozone, sulphur dioxide, nitrogen dioxide, and particles were all found to have significant associations with daily hospital admissions for asthma, but there was a lack of consistency across the age groups in the specific pollutant. These associations were not explained by confounding by airborne pollens nor was there convincing evidence that the effects of air pollutants and airborne pollens interact in causing hospital admissions for asthma.

Atmospheric birch (Betula) pollen in Europe: Trends and fluctuations in annual quantities and the starting dates of the seasons

Abstract Long term observations of atmospheric pollen offer the possibility of studying patterns in fluctuations in the airborne pollen presence. In this study, birch pollen measured at five monitoring stations in Europe with records of 18 to 30 years, have been analysed comparatively on three aspects: trends and fluctuations of annual sums of daily concentrations, and starting dates of airborne presence. The results show weakly rising trends at all five stations. The observed fluctuations in airborne birch pollen quantities are suggestive of synchronous, alternatingly cyclic rhythms, beit with a-synchronous aberrant years and phase shifts. For the starting dates of the birch pollen season the air temperature during the preceding 4 decades-of-days are of decisive importance.

The trend to earlier birch pollen seasons in the U.K.: A biotic response to changes in weather conditions?

Records of the start of Birch pollen seasons monitored at three sites in the UK for periods of up to forty two years indicate a recent trend for the pollen seasons to begin earlier. This trend shows a close relationship to an increase in cumulative temperatures in the months of January, February and March recorded near each of the sites during the study period.

Quantitative trends in annual totals of five common airborne pollen types (Betula, Quercus, Poaceae, Urtica, and Artemisia), at five pollen-monitoring stations in western Europe

The existence of long-term (20–33 years) trendsin the annual totals of daily airborne pollenconcentrations of five common and/or allergenicwind pollinating taxa was evaluated at fivepollen-monitoring stations in western Europe:Delmenhorst (D), Helmond (NL), Brussels (B),Leiden (NL), and Derby (UK). At all stations,identical or comparable volumetric traps wereused to sample pollen from the air. For grasspollen no increasing or decreasing trends werefound at any station. Trends for birch pollenand oak pollen are increasing, but notsignificant at the stations with the higherannual totals (Delmenhorst and Helmond),probably due to strong year-to-yearfluctuations. At all five stations significantincreasing trends for stinging nettle pollenwere observed. Trends for mugwort pollen aresignificant at all stations, but in differentdirections. Longer periods of observations areneeded to arrive to more definitive conclusionsabout trends in airborne pollenconcentrations.

Thunderstorm-related asthma--the epidemic of 24/25 June 1994.

Background A large epidemic of asthma occurred following a thunderstorm in southern and central England on 24/25 June 1994. A collaborative study group was formed.

A Comparative Analysis of Daily Variations in the Gramineae Pollen Counts at Córdoba, Spain and London, UK

Abstract The features of five grass pollen seasons from two areas of contrasting climate were investigated and the relative importance of the variables controlling daily variations were determined. The records from London, UK (temperate maritime climate) and Cordoba, Spain (mediterranean climate) were analysed in relation to meteorological factors. The length of the seasons differs a great deal between the two locations and from year to year. However the total cumulative catches and the number of days with counts over 50 grains metre-3 are similar for the two locations. Regression analysis of standardised daily average pollen counts shows clearly that for London, maximum and average temperatures are the most important factors influencing daily variation. In the case of Cordoba this relationship holds true for the period from the start of the season until the peak count, but after this the relationship becomes negative. Hours of sunshine and humidity are also important. The negative effect of increased hum...

The Effects of Patterns in Climate and Pollen Abundance on Allergy

Recent climatic trends in Europe have been examined in the context of longer term variations and vegetation zonation. The most recent computer models of future climatic changes resulting from increasing carbon dioxide emissions are discussed in relation to the possible impacts that the predicted climatic shifts may have on the distribution and abundance of the main allergenic pollen types. The probable repercussions of these changes on the patterns and incidences of seasonal allergic rhinitis are considered. This study focuses on pollen from Betula, the Poaceae, Ambrosia, Parietaria and Olea, but also examines the implications of climatic change for other aeroallergens, including those from various crops such as Brassica species (oil‐seed rape) and Helianthemum (sunflowers). In the case of natural distributions, the response of the plants to climatic changes are viewed in relation to the potential migration rates of the species. For agricultural crops, shifts in the location of productive areas involve agricultural economics both at the national and European community levels. In addition to broad regional impacts, this study examines the influence of increasing ultraviolet radiation on pollen production over various areas of Europe, and considers the effect of changing airflow trajectories on the long‐range transport of pollen with pollution from central and northern Europe into Scandinavia.

PCR to predict risk of airborne disease

Plant, animal and human diseases spread by microscopic airborne particles have had major economic and social impacts during history. Special air-sampling devices have been used to collect such particles since the 19th century but it has often been impossible to identify them accurately. Exciting new opportunities to combine air sampling with quantitative PCR to identify and count these particles are reviewed, using crop pathogen examples. These methods can be used to predict the risk of unexpected outbreaks of airborne diseases by identifying increases in pathogen inoculum or genetic changes in pathogen populations that render control ineffective. The predictions can provide guidance to policymakers, health professionals or the agricultural industry for the development of strategies to minimise the risk of severe pandemics.

Pollen counts in relation to the prevalence of allergic rhinoconjunctivitis, asthma and atopic eczema in the International Study of Asthma and Allergies in Childhood (ISAAC)

Background Although pollens are major allergens associated with allergic rhinoconjunctivitis and asthma, there is little information about the relative prevalence of these conditions in populations with different pollen exposures.

Diurnal variation of pollen concentration in the air of north-central london

Abstract Pollen concentrations recorded during three years sampling in north-central London have shown distinctive diurnal variations. This paper identifies these patterns for three pollen taxa and attempts to account for the variations observed. The diurnal variations identified are interpreted in relation to meteorological conditions, pollen source area and phenological patterns of pollen release. A hypothesis of pollen dispersal to the sampling site is suggested.