An aerobiological study of pollen and mold of a stations and change of prevalence of allergic diseases in school-aged children for 7 years in Korea

Abstract

In a large number of allergic individuals, pollens and molds are important causative and triggering agents in respiratory allergy. It is essential to survey the pollen and mold around the patient`s environment for the diagnosis and treatment of airborne allergy. Recently allergic diseases were gradually increased since early 1990s in school aged childhood moreover the seasonal and regional variations of pollen and mold have been changed in Korea. The Korean peninsula is located in a Temperate Zone (the geographic position is 127-131º East longitude and 33-41º North latitude) and has four distinct seasons. In early March, the trees burst into leafy splendor to mark the beginning of spring. During the relatively hot and rainy summer season, the average temperature is 200C (680F). The monsoon rains usually begin at the end of June and last until late July. The coming of autumn in late September brings continental winds and clear, dry weather. December to February is cold and dry with occasional rain or snow. Airborne particles carrying allergens were collected daily from nationwide 8 stations (Seoul, Guri, Cheongju, Daegu, Kwangju, Busan, Kangneung, and Cheju) by using 7 days - Burkard sampler (Burkard Manufacturing Co Ltd, Hertfordshire, UK) for 7 year in South Korea (July 1, 1996 - June 30, 2003). They were counted and recorded along with the weather in South Korea. The Korean version of written questionnaire for allergic diseases such as asthma, allergic rhinitis, atopic dermatitis, food allergy, and allergic conjunctivitis following the guidelines suggested by ISAAC was developed. Total of 42,886 children in 1995 and 43,047 in 2000 were selected from 68 schools across the nation. The 12-month prevalence of wheeze in 2000 was decreased from 17.0% to 13.0% in 6-12 yr olds and from 9.5% to 4.9% in 13-15 yr olds respectively, when compared to the data of 1995 survey. However, the lifetime prevalence of asthma diagnosis depicted the increasing pictures of 7.7% to 9.1% in 6-12 yr olds and 2.7% to 5.3% in 13-15 yr olds, respectively. On the other hand, the lifetime and 12 month prevalence of rhinitis in 2000 survey was stationary from 12.2% to 12.4% in 6-12 yr olds, but increased in 1.0% to 13.7% in 12-15 yr olds, respectively, compared to the data of 1995 survey. Airborne pollen has two peak seasons that is May (1506 grains/m3/day) and September (857 grains/m3/day) in Korea. The peak season for mold (4936 spores/m3/day) was June. There was the tree pollen seasons from the middle of February to late July, then followed during the grasses and weed season from the middle of July to the end of October. Birch pollen appeared first, followed by alder, oak, and pine. Alder and birch are the common pollens in early spring. Ragweed was one of the most common pollen of autumn in Korea. In skin prick test, Mugwort was the most common positive, followed by ragweed mix, alder, birch, grasses mix among the pollen extracts in Korean school aged children. The seasonal variation of prevalence of allergic rhinitis was markedly increased during spring (April to June) and fall (September to November).But the prevalence of asthma in school aged childhood was not correlated to the seasonal variation of pollen and mold.