Quantifying PM_2.5 capture capability of greening trees based on leaf factors analyzing.

Area of Science:

• Environmental Science
• Botany
• Urban Ecology

Background:

• Particulate matter (PM2.5) poses significant risks to human health.
• Urban trees play a crucial role in mitigating air pollution.
• Quantitative data on how leaf morphology influences PM2.5 capture by trees is limited.

Purpose of the Study:

• To investigate the relationship between leaf morphology and PM2.5 capture efficiency in urban trees.
• To compare the PM2.5 capture capabilities of different tree species in Beijing and Chongqing.
• To identify key leaf morphological traits that enhance PM2.5 deposition.

Main Methods:

• Experimental chamber study evaluating PM2.5 capture by 25 tree species.
• Selection of leaf morphological indexes: groove proportion, leaf hair, stomatal density, and stomata size.
• Comparative analysis of broadleaf and coniferous species in Beijing and Chongqing.

Main Results:

• Groove proportion and stomata size were significantly correlated with PM2.5 capture quantity.
• Leaf hair and stomatal density showed no significant positive correlation with PM2.5 capture.
• Broadleaf species demonstrated higher PM2.5 capture per leaf area; conifers showed higher capture per tree.
• Significant variations in PM2.5 capture were observed between species in Beijing and Chongqing, linked to differing leaf morphology.

Conclusions:

• Leaf morphology, specifically groove proportion and stomata size, is critical for PM2.5 capture by urban trees.
• Both broadleaf and coniferous trees have distinct advantages in PM2.5 capture depending on the metric (per area vs. per tree).
• Urban planning for air pollution reduction should consider species-specific leaf traits and local environmental conditions (climate, pollution).