Overheated trees are contributing to urban air pollution

Air Pollution in Los Angeles: The Role of Plants and Sustainable Development Goals (SDGs)

Introduction

Air pollution in Los Angeles from cars and human activity is getting a boost from the city’s plants, some of which emit chemicals in response to rising temperatures and drought. This article explores the impact of plant emissions on air pollution in Los Angeles and emphasizes the importance of addressing this issue in line with the Sustainable Development Goals (SDGs).

The Role of Plants in Air Pollution

Many plants, including jacaranda trees and eucalyptus, emit a class of compounds called terpenoids. While these compounds act as chemical signals and antioxidants for the plants, they can react with other pollutants in the atmosphere to produce harmful ozone and particulate pollution (PM2.5). This phenomenon highlights the need to control both plant emissions and human-caused air pollution.

Measurement of VOC Emissions in Los Angeles

Researchers at Forschungszentrum Jülich conducted a study to measure volatile organic compound (VOC) emissions in Los Angeles. They flew a plane above the city over several days in June 2021 and used an on-board mass spectrometer to identify concentrations of more than 400 types of VOCs in the air. Simultaneous 3D measurements of wind speed helped isolate the molecules originating from the city and those coming from elsewhere.

Findings and Implications

The study found that terpenoids dominated VOC emissions in many parts of Los Angeles, especially in areas with high vegetation and on hot days. The researchers observed that terpenoid emissions increased even in downtown areas with fewer plants but higher temperatures. The reasons behind this increase are still unclear, but it could be a response to heat or water stress. Additionally, hotter temperatures also led to increased VOC emissions from human sources such as gasoline, paint, and personal care products.

The observed link between heat and emissions suggests that climate change will contribute to air pollution. The researchers projected that with the projected 3°C warming in Los Angeles by the middle of the century, the effect of VOCs on ozone formation could double, and PM2.5 pollution could increase by 40%. These findings highlight the urgent need to address climate change and reduce human sources of air pollution.

Importance of Direct Observation and Urban Greening

Direct observations, such as the one conducted in this study, are crucial for building accurate models to predict future air pollution levels. The study also emphasizes the importance of urban greening programs and the selection of plant species in cities. The choice of vegetation can have a significant impact on air quality and should be aligned with the SDGs.

Conclusion

The role of plants in contributing to air pollution in Los Angeles underscores the need for comprehensive strategies to address this issue. By focusing on reducing human sources of air pollution, mitigating climate change, and promoting sustainable urban development, cities can work towards achieving the SDGs and ensuring clean and healthy environments for their residents.

Source: newscientist.com