Chamber and Field Studies demonstrate Differential Amb a 1 Contents in Common Ragweed Depending on CO₂ Levels

Although atmospheric carbon dioxide (CO₂) has no apparent direct effect on human health, it does have direct effects on plants. The present study evaluated the influence of increased CO₂ levels on the concentration of allergens from common ragweed pollen by setting up a chamber study to model future air conditions and a field study to evaluate current air conditions. For the chamber study, we established 20 ragweed plants in an open-top chamber under different CO₂ levels (380–400, 500–520, 600–620, and 1,000–1,100 parts per million [ppm]). For the field study, we established ragweed plants in rural (Pocheon, Gyeonggi-do; mean CO₂ 320±54.8 ppm) and urban (Gangnam, Seoul; mean CO₂ 440±78.5 ppm) locations. Seeds of the common ragweed (Ambrosia artemisiifolia) were obtained from Daejin University. The Amb a 1 protein content of pollen extracts was quantified using a double sandwich enzyme-linked immunosorbent assay. In our chamber study, the median concentration of Amb a 1 in pollen increased with increasing in CO₂ concentration (1.88 ng/µg in 380–400 ppm CO₂; 3.14 ng/µg in 500–520 ppm CO₂; 4.44 ng/µg in 600–620 ppm CO₂; and 5.36 ng/µg in 1,000–1,100 ppm CO₂). In our field study, we found no significantly different concentration of Amb a 1 between the pollen extracts at the Pocheon (mean±standard deviation, 1.63±0.3 ng/µg pollen in 320±54.8 ppm CO₂) and the Gangnam (2.04±0.7 ng/µg pollen in CO₂ in 440±78.5 ppm CO₂) locations, although the concentration of Amb a 1 was increased in the Gangnam than in the Pocheon locations. Our results suggest that future increases in CO₂ levels to more than 600 ppm will significantly elevate the Amb a 1 content in common ragweeds, although the current different CO₂ levels do not cause differences in the Amb a 1 content of ragweed pollen.

Evaluation of the association between pollen count and the outbreak of allergic disease

PURPOSE: This study focused on the evaluation of the relation between pollen concentration and the outbreak of allergic disease (symptom index), and this outcome would be necessary to upgrade risk grade for the pollen forecasting system. METHODS: Airborne particles carrying allergens, such as pollen, were collected daily at the Seoul and Guri area by using 7-day Burkard samplers for 6 years. A total of 596 Subjects were recruited from Hanyang University Seoul Hospital (n=144 for spring, n=139 for autumn), and Hanyang University Guri Hospital (n=157 for spring, n=156 for autumn). Symptom index was evaluated and recorded by phone calling to study subjects daily or asking questionnaire when they visit outpatient clinic every week. Statistical analysis of data was performed by using correlation coefficients and regression models with time series graph. RESULTS: Two peak seasons of pollen concentration were May and September in Korea. In skin prick tests, the sensitization rate to ragweed pollen was gradually increased in children. In the same period, sensitization rates to airborne pollen, especially oak, birch for spring, and Japanese hop for autumn were increased annually. There was a significantly relationship between symptom index of allergic patients and allergic pollen concentrations in this study. Especially symptom index was significantly correlated to the concentration of oak pollen of day 1 in spring and to the concentration of Japanese hop pollen of day 0 in autumn. CONCLUSION: Sensitization rates to pollens increased annually. There is a significant relationship between allergy symptom index and pollen concentration. There remains to confirm the Korean own risk grade of pollen allergy.