In California, vehicle emissions have been on the decline thanks to environmental policies and advancements in technology. However, since 2010, other sources of pollution have emerged, leading to the stubborn refusal of microscopic airborne particles and ground-level ozone to decrease. Surprisingly, many of these ‘secondary sources’ are the trees and shrubs that line the city streets.
To get a clearer picture of these emissions, a team of US researchers conducted nine flights over Los Angeles in June 2021. They used an on-board mass spectrometer to measure volatile organic compounds (VOCs) directly, providing a more accurate representation of the fluctuating concentrations of these pollutants. Unlike previous methods that relied on estimates or models, this approach allowed for real-time measurements multiple times a second.
The researchers discovered that botanical sources, such as trees and plants, contribute significantly to the formation of secondary organic aerosols. Compounds like isoprene, monoterpenes, and sesquiterpenes released by these sources can lead to the creation of harmful particulates and ozone. With these emissions increasing in hot weather and drought conditions, the problem is expected to worsen as summers become hotter.
Air pollution, whether from vehicle emissions or botanical sources, remains a significant health concern globally. Fine particles and ozone in the air have been linked to various health issues, including heart disease, respiratory illnesses, and increased mortality rates. Identifying and mitigating sources of VOCs is crucial in addressing this public health crisis, especially in urban areas where pollution levels are high.
Volatile organic compounds (VOCs) play a key role in the formation of harmful pollutants. These chemicals can directly impact human health and react with sunlight and other gases in the atmosphere to create particulates and ozone. With millions of premature deaths attributed to ambient airborne pollution each year, there is a pressing need to address the sources of VOCs in our cities.
While industrial sources of VOCs are well-known, the contributions of botanical sources are often overlooked. Trees and plants release terpenoids, which can account for a significant portion of VOC emissions. As temperatures rise, the emissions from these biogenic sources may also increase, posing a challenge for mitigating air pollution in the future.
Despite the contribution of botanical sources to pollution, reducing green spaces is not the solution. These spaces play a crucial role in keeping cities cooler and providing other health benefits. Some plants can even help remove VOCs from the air. Understanding how factors like drought affect biogenic VOC emissions and identifying low-emission plant species can help maximize the benefits of green spaces while addressing air quality concerns.
Leave a Reply