East Asia is getting greener—and that transformation may be changing the air millions of people breathe. A new study from Pusan National University has found that climate-driven shifts in vegetation can substantially alter emissions of plant-derived gases, changing the atmospheric chemistry behind ground-level ozone and fine particulate pollution. The findings suggest that air-quality models relying on vegetation maps from more than two decades ago may be missing a crucial part of the region’s pollution story.
Plants are not passive components of the climate system. Forests, grasslands, crops, and other vegetation release biogenic volatile organic compounds, or BVOCs, into the atmosphere. Among the most important are isoprene and monoterpenes, highly reactive gases that can interact with sunlight, nitrogen oxides, and other atmospheric chemicals. These reactions can produce ozone near the ground and contribute to biogenic secondary organic aerosols, microscopic particles that can penetrate deep into the lungs.
The researchers were particularly concerned that many atmospheric chemistry models still use vegetation information from 2003 to estimate these natural emissions. East Asia has undergone major ecological changes since then, driven by warming temperatures, altered rainfall, land-use change, urban expansion, forest development, and shifting agricultural patterns. When the vegetation map does not reflect current conditions, the emissions calculated by the model may also be out of date, potentially distorting forecasts of air pollution and assessments of climate-related environmental risk.
To test the effect, the team used the WRF-Chem atmospheric chemistry model together with the MEGAN biogenic emissions model. They replaced the default 2003 vegetation dataset with satellite-derived observations from 2024, while keeping the model configuration and meteorological conditions consistent. This design allowed the scientists to isolate the influence of vegetation change itself, rather than mixing it with the effects of changing weather, emissions from vehicles and industry, or other factors that also affect air quality.
The satellite observations showed an overall increase in vegetation across East Asia, although the pattern was far from uniform. Several areas of China experienced pronounced greening, while parts of Japan showed localized declines. Such differences matter because the quantity and chemical composition of BVOCs depend not only on how much vegetation is present, but also on the types of plants growing in a region. A larger forested area, for example, may emit a different mixture of reactive compounds than cropland, shrubland, or urban vegetation.
When the updated vegetation information was incorporated into the model, calculated emissions of BVOCs changed significantly. Those changes were then transmitted through the atmosphere’s chemical network, modifying concentrations of ozone and biogenic secondary organic aerosols. The strongest responses appeared in suburban areas, where vegetation was sufficiently abundant to influence emissions and nitrogen oxides were present at levels capable of driving secondary pollutant formation.
The results also reveal why the relationship between greening and air quality is not straightforward. In heavily built-up urban areas, vegetation changes were relatively limited, even though nitrogen oxide concentrations were high. That restricted the overall response to updated plant data. In rural regions, vegetation changes were often more substantial, but nitrogen oxide levels were too low to support the same degree of ozone and aerosol production. Suburban environments occupied the critical middle ground, combining enough vegetation with enough nitrogen oxides to amplify atmospheric reactions.
This interaction reflects a central principle of atmospheric chemistry: pollutant formation depends on combinations of ingredients, not on a single emission source. BVOCs can either contribute strongly to ozone production or have a more limited effect depending on the amount of nitrogen oxides, sunlight, temperature, and other chemical conditions. The same increase in vegetation can therefore produce different air-quality outcomes in different locations. Greening is not automatically beneficial or harmful; its atmospheric consequences depend on the surrounding chemical environment.
“Our results show that updating vegetation information alone can substantially change biogenic emissions, O₃, and biogenic secondary organic aerosols,” says Professor Hyo-Jung Lee of Pusan National University, who led the study with Research Professor Yu-Jin Jo and collaborators including Dr. Younha Kim of the International Institute for Applied Systems Analysis. The researchers argue that regularly refreshed satellite observations should become a standard component of atmospheric chemistry modeling, especially as climate change continues to reshape ecosystems.
The study focused on August 2024, a period when vegetation activity is near its annual peak in much of East Asia. The authors say future research will extend the analysis across additional seasons and longer time periods, allowing scientists to determine whether the observed effects persist during spring, autumn, and winter, when plant activity and atmospheric conditions differ. More accurate vegetation data could ultimately improve operational air-quality forecasts, strengthen pollution-control strategies, and help policymakers anticipate how ecosystem change will interact with emissions from human activities.
Subject of Research: Not applicable
Article Title: Impacts of climate-driven vegetation changes on air quality over East Asia: Modulation of biogenic VOC emissions and secondary pollutants
News Publication Date: 15 June 2026
Web References: https://www.sciencedirect.com/science/article/abs/pii/S0013935126007231
References: Environmental Research. DOI: 10.1016/j.envres.2026.124392
Image Credits: Professor Hyo-Jung Lee and Research Professor Yu-Jin Jo, Pusan National University, Republic of Korea
Keywords: climate change, East Asia, vegetation change, air quality, ozone, biogenic volatile organic compounds, secondary organic aerosols, satellite observations, atmospheric chemistry, nitrogen oxides
