Does the increase in ambient CO2 concentration elevate allergy risks posed by oak pollen?

Abstract

Oak pollen is a major respiratory allergen in Korea, and the distribution of oak trees is expected to increase by ecological succession and climate change. One of the drivers of climate change is increasing CO, which is also known to amplify the allergy risk of weed pollen by inducing elevated allergenic protein content. However, the impact of CO concentration on tree pollen is not clearly understood due to the experimental difficulties in carrying out extended CO treatment. To study the response of pollen production of sawtooth oak trees (Quercus acutissima) to elevated levels of ambient CO, three open-top chambers at the National Institute of Forest Science in Suwon, Korea were utilized with daytime (8 am-6 pm) CO concentrations of ambient (× 1.0, ~ 400 ppm), × 1.4 (~ 560 ppm), and × 1.8 (~ 720 ppm) treatments. Each chamber had three sawtooth oak trees planted in September 2009. One or two trees per chamber matured to bloom in 2016. Five to six catkins were selected per tree and polyethylene bags were attached to collect pollen grains. The total number of catkins per tree was counted and the number and weight of pollen grains per catkin were measured. Oak allergen-Que a 1 (Allergon Co., Uppsala, Sweden)-was extracted and purified to make an ELISA kit by which the antigen levels in the pollen samples were quantified. Total pollen counts per tree of the × 1.4 and × 1.8 treatments showed significant increase of 353 and 1299%, respectively, from the × 1.0 treatment (p < 0.001). Allergenic protein contents at the × 1.4 and × 1.8 treatments also showed significant increase of 12 and 11%, respectively (p = 0.011). The × 1.8 treatment induced significant difference from the × 1.0 treatment in terms of pollen production and allergenic protein content, whereas the × 1.4 treatment showed mixed significance. In summary, the oak trees under the elevated CO levels, which are expected in the changing climate, produced significantly higher amount of pollen and allergenic protein than under the present air conditions.

Increased sensitization rates to tree pollens in allergic children and adolescents and a change in the pollen season in the metropolitan area of Seoul, Korea

“…Second, climate change could increase both the level of allergenic pollens, and, in turn, allergic symptoms that are dependent on the exposure level, and the duration of the pollen season 2,3 . Finally, the CO 2 concentration, together with warmer temperatures, also increases pollen concentrations, but it might also alter the allergenicity or allergen concentration of the pollen and therefore symptom severity 11,12 …”

“…In an experimental study, warming and increases in the CO 2 level were shown to increase pollen production 9,10 . Other studies similarly reported that an elevated CO 2 concentration resulted in both early pollen production by trees and greater seasonal pollen production 11,12 . In addition, weather patterns influence the movement and dispersion of aeroallergens in the atmosphere through the action of wind and rainfall, and depending on the atmospheric stability.…”

Increased sensitization rate to tree pollen of allergic children and altered pollen season in Seoul metropolitan area, Korea

“…And increased CO 2 might alter the allergenicity, or allergen concentration of the pollen, and symptom severity. 11,12 The pollen season was expanded and the concentration of pollens and sensitization rate to pollens were increased from year to year in the present study. Sensitization to allergens is an important step in the development of allergic diseases.…”

“…9,10 Elevated CO 2 concentrations resulted in early pollen production from trees and greater seasonal pollen production. 11,12 In addition, weather patterns influence the movement and dispersion of all aeroallergens in the atmosphere through the action of winds, rainfall and depending on the atmospheric stability.…”

An Overview of Rising CO2and Climatic Change on Aeroallergens and Allergic Diseases

“… 30 Research with sawtooth oak trees ( Quercus acutissima ) at projected elevated CO 2 concentrations of 560 and 720 ppm indicated substantial and significant increases in pollen production per tree as well as increases in allergenic protein concentration. 31 …”