One key piece of information for analyzing and understanding air pollution is comprehensive data on particle density in the air that varies with height above ground level (known as the "vertical profile" by atmospheric scientists). This can be investigated using the atmospheric LiDAR technology, which the NARIT atmospheric science research team has designed and is currently developing.
LiDAR or Light Detection and Ranging is a technology that uses laser light in conjunction with a sensor to detect scattered light. It functions similarly to parking sensors; however LiDAR generally uses laser light sources, and the scattered light can provide information such as the distance between the tiny particles that the light is scattering.
The use of LiDAR in atmospheric science research is one method for studying air masses in our atmosphere. The atmospheric LiDAR developed by NARIT operates at a wavelength of 532 nanometers by pointing a laser light source into the sky and receiving the scattered light from airborne particles from the ground up to 10 kilometers above. This technology enables researchers to measure the level of particulate matter at all hours of the day and night.
Laser light scattered from aerosol particles in the air provides important information about the atmosphere in the planetary boundary layer (PBL). Different types and sizes of particles return different signals, providing information about the density of different types of particles at various heights, all the way to the top layer where pollution mixes with the atmosphere (mixing height), which plays an important role in the daily change of the PM2.5 index and is a factor in pollution release into the upper atmosphere. Knowing the distribution of dust particles, and where dust accumulates the greatest at what heights, is one of the key elements that can help us better understand the PM2.5 problem.
Although commercial LiDAR instruments are currently available, they are often costly and require extensive maintenance. Thus, NARIT designed and developed its own LiDAR for use in atmospheric science research. In addition to being able to provide the instruments that meet the specific demands of researchers at a reasonable cost, it also enhances the capabilities and potential of personnel in advanced technology and engineering, which is also aligned with the missions of NARIT.
NARIT's atmospheric LiDAR is now undergoing design, prototype manufacturing, and testing to assure optimal performance. This LiDAR instrument is one of the tools used by NARIT atmospheric science research team uses to investigate and better understand Thailand's pollution and PM2.5 problems.