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A large source of low-volatility secondary organic aerosol
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Forests emit large quantities of volatile organic compounds (VOCs) to the atmosphere. Their condensable oxidation products can form secondary organic aerosol, a significant and ubiquitous component of atmospheric aerosol 1,2, which is known to affect the Earth’s radiation balance by scattering solar radiation and by acting as cloud condensation nuclei 3. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incom- plete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non- volatile organic vapours4–6, but the sources and compositions of such vapours remain unknown. Here we investigate the oxidation of VOCs, in particular the terpene a-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the for- mation of large amounts of extremely low-volatility vapours. These vapours form at significant mass yield in the gas phase and condense irreversibly onto aerosol surfaces to produce secondary organic aero- sol, helping to explain the discrepancy between the observed atmo- spheric burden of secondary organic aerosol and that reported by many model studies2. We further demonstrate how these low-volatility vapours can enhance, or even dominate, the formation and growth of aerosol particles over forested regions, providing a missing link between biogenic VOCs and their conversion to aerosol particles. Our findings could help to improve assessments of biosphere–aerosol– climate feedback mechanisms 6–8, and the air quality and climate effects of biogenic emissions generally.
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EPA and the Army Corps’ Proposed Rule to Define “Waters of the United States”
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Excerpt from summary : According to the agencies, the proposed rule would revise the existing regulatory definition of “waters of the United States” consistent with legal rulings—especially the Supreme Court cases—and science concerning the interconnectedness of tributaries, wetlands, and other waters to downstream waters and effects of these connections on the chemical, physical, and biological integrity of downstream waters. Waters that are “jurisdictional” are subject to the multiple regulatory requirements of the CWA: standards, discharge limitations, permits, and enforcement. Non-jurisdictional waters, in contrast, do not have the federal legal protection of those requirements.
This report describes the March 25 proposed rule and includes a table comparing the existing regulatory language that defines “waters of the United States” with that in the proposal.
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Video: Climate Change The Cost of Inaction
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The Earth's climate is changing at an unprecedented rate. Climate change is already having impacts on people's lives across the country.
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USDA Provides $328 Million to Conserve Wetlands and Farmland, Boost Economy
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Agriculture Secretary Tom Vilsack announced today that $328 million in conservation funding is being invested to help landowners protect and restore key farmlands, grasslands and wetlands across the nation. The USDA initiative will benefit wildlife and promote outdoor recreation and related sectors of the economy.
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Primary Influences on Water Temperature for Inland Streams
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The COMET Program is pleased to announce the publication of the new lesson, "Primary Influences on Water Temperature for Inland Streams". The temperature of inland streams, rivers, and reservoirs affects aquatic wildlife, riparian vegetation, and infrastructure.
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Pricing the Priceless: Ecosystem Services Science at USGS
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Nature's products and services are essential not only to the ecosystems that provide them, but also to the people and societies built on them. Factoring their value into cost-benefit analyses is an important part of smart planning. But that raises a new question—how to assign value to ecosystem services?
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Canaan Valley Institute (CVI)
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Canaan Valley Institute (CVI) is driven by a mission to ensure the Appalachian region has healthy streams — a critical economic engine for rural communities. CVI’s approach for clean and healthy rivers creates positive results environmentally AND economically.
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US Forest Service Proposes New Management Practices for Stewardship of Water Resources
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The U.S. Forest Service today announced its intent to strengthen agency management direction for groundwater resources and the use of best management practices to improve and protect water quality on national forests and grasslands. This action is an integral component of watershed stewardship and land management.
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NRCS and Forest Service Partner to Improve Forest Health
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Agriculture Under Secretary for Natural Resources and Environment Robert Bonnie announced today a multi-year partnership between the U.S. Forest Service and the Natural Resources Conservation Service (NRCS) to improve the health and resiliency of forest ecosystems where public and private lands meet across the nation.
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Nexus 2014: Water, Food, Climate and Energy Conference
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The Water Institute at the University of North Carolina at Chapel Hill and collaborators will host the Nexus 2014: Water, Food, Climate and Energy Conference to examine the thoughts and actions related to a nexus approach.
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