A recent study reveals important findings indicating that the climate impacts of newly formed particles in cities have been significantly underestimated.
Particles are vital for regulating the climate, affecting processes like cloud development and radiation balance. Previous research in urban settings has primarily concentrated on primary particles—those that come directly from sources such as vehicle exhaust and industrial emissions—while newly formed particles, which arise from atmospheric reactions, have not received adequate attention in terms of their climatic influence.
A recent publication in One Earth has highlighted that the climate consequences of new particles in urban settings have been largely overlooked.
“For a precise evaluation of the climate impacts of particles, thorough long-term vertical observations are essential,” states Academician Markku Kulmala from the Institute for Atmospheric and Earth System Research INAR at the University of Helsinki. This emphasizes the need for improved observational techniques that consider different altitudes to enhance our understanding of how aerosols behave in urban environments.
Increased particle formation at higher altitudes in cities
The research team used sophisticated measurement technology from a 325-meter meteorological tower in Beijing to study particle formation at various elevations above the city. Findings indicate that particle creation is more significant at higher altitudes, where increased sulfuric acid levels and relative humidity support the growth of particles. This is especially relevant in urban centers, where pollution and atmospheric conditions can vary greatly, which leads to different mechanisms for particle growth compared to rural regions.
“The increased formation of particles aloft indicates that while surface-level measurements are informative, they may miss the complete picture of particle behavior, especially in heavily populated cities,” comments Wei Du, a primary investigator in the study. This underscores the need to explore the air above city skylines to gain a better understanding of atmospheric dynamics in urban areas.
The climatic influence of new particles
When gaseous compounds associated with human activities are transported to the upper layers of the atmosphere, they stimulate the development of particles, allowing them to function effectively as cloud condensation nuclei (CCN), which are vital for cloud creation and local climate management. The study suggests that the role of new particles on CCN has been underestimated by about 20%. Therefore, grasping the vertical aspects of urban atmospheric dynamics is crucial for understanding how particulate matter affects climate.
The findings of this research are significant not only for scientific discourse but also for urban policy and planning.
“As cities increasingly confront air pollution and climate-related issues, understanding the vertical profiles of atmospheric processes can lead to more effective interventions to address their effects on both climate and public health,” Wei adds.
This study is a collaborative effort among researchers from the University of Helsinki, the Chinese Academy of Sciences, and several other partners.
“The Beijing 325 m Meteorological Tower serves as a unique research facility for atmospheric and climate science in megacities. We are excited to work together with international allies to tackle climate change,” comments Yele Sun, Professor at the Chinese Academy of Sciences.
