Pollen Severely Affects the Atmosphere

- Remote investigation using laser identified the distribution of pollen in the atmosphere for the first time in the world.
- Pollen goes up 2km high in the middle of the day and influences the temperature by diffusing the light.

 

 

 

 

 

 

□ The people’s health is threatened by fine dust-induced air pollution. A Korean research team has identified for the first time in the world that pollen could severely affect atmosphere environments and climate change, using a laser-based remote investigation device LIDAR (LIght Detection And Range). This study is expected to serve as foundations for identifying the effects of pollen on global warming and for highly accurate pollen forecasts.

❍ This study has been jointly conducted by a research team led by GIST (Gwangju Institute of Science and Technology) President and Professor Young Joon Kim and Professor Detlef Müller at the University of Hertfordshire in the UK, and Dr. Young Min Noh, a research professor at GIST, was nominated as the first author. The study was funded by the Meteorological Technology Development Project of the Korea Meteorological Administration and the Basic Research Support Project of the Korea Research Foundation. The results of this study* were published in Atmospheric Chemistry and Physics and Atmospheric Environment, renowned journals in the field of atmospheric environment, and last month online science news service ‘EurekAlert’ covered this project both in English and German.

* (Titles of the papers: Investigation of the diurnal pattern of the vertical distribution of pollen in the lower troposphere using LIDAR; and Influence of biogenic pollen on optical properties of atmospheric aerosols observed by lidar over Gwangju, South Korea)

□ (Background) Pollen diffused into the atmosphere is known as a major cause of allergy reactions. As climate change has contributed the increase of the amount of pollen and its toxicity, it is expected that pollen will have increasingly more influence on the people’s health. For this reason, many recent studies have focused on pollen and its diffusion and distribution into the atmosphere.

❍ Against this backdrop, the joint research team noticed that pollen naturally released from plants are clearly differentiated from other fine dusts in size and shape (Figure 1) and for the first time in Korea introduced LIDAR, a laser-based advanced remote investigation device designed to continuously detect fine dusts real time, to the observation and detection of pollen in the atmosphere.

□ (Results) Using LIDAR, the team has demonstrated that in urban areas pollen is mostly distributed between the ground and 1.5 – 2.0 km high in the lower troposphere. They also demonstrated that pollen is detected near the ground in the morning but is diffused to the highest elevation by noon (Figure 2). The laser device LIDAR for the first time revealed that pollen is distributed up to 2 km from the ground.

❍ The research team also recognized that other fine dusts are generally round-shaped but pollen has various geometric forms and calculated the light extinction coefficient of pollen for the first time in the world based on optical division between pollen and other fine dusts.

- A light extinction coefficient is a variable to calculate optical depth that is an indicator of optical turbidity of the air. The study demonstrated that the calculated light extinction coefficient of pollen can be used to calculate pollen’s optical depth. Based on this calculation, they showed that the contribution of pollen optical depth to total aerosol optical depth was 2 – 30% (Figure 3). These results are expected to serve as foundations to quantitatively investigate the influence on pollen on atmospheric temperature changes on the Earth.

□ (Significance) Though spatially limited to a certain area in Korea (Gwangju), this study has produced the first set of continuous, real time data on the distribution and diffusion of pollen in the atmosphere. It expected that the results of this study would serve as foundations for highly accurate pollen forecasts, which reaches its peak in every April to May, thereby significantly contributing to the people’s health.

- The study also showed that pollen could influence optical environment changes in the atmosphere for the first time in the world. This would underpin the hypothesis that high concentration pollen generated in forest areas in the Northern Hemisphere (for example; Alaska, Canada, Scandinavia, and Siberia) may influence temperature changes of the entire planet.