Volatile Organic Compounds (VOCs) Contribute to Ozone
Volatile organic compounds (VOCs) contribute to the formation of ground-level ozone, which is harmful to human health and vegetation when present at high enough concentrations. VOCs react with nitrogen oxides (NOx) in the presence of sunlight to form ozone. Thus, to reduce the chances of ozone formation both NOx and VOC emissions are regulated in regions with severe ozone issues such as the San Joaquin Valley. Sources of VOCs come from a wide array of products such as gas and diesel fuels, paints, hairsprays, pesticides, cows, wine fermentation, etc.
EPA sets limits on the amount of ozone allowed in the air under the Clean Air Act. As part of the Clean Air Act each state that is not in compliance with the limits must submit a State Implementation Plan (SIP) for achieving and maintaining federal ambient air quality standards, including the standard for ozone. California’s Air Resources Board (ARB) submits the SIP but Air Districts and Department of Pesticide Regulation (DPR) all contribute to the development of a plan to reduce sources of VOC and NOx in regions not in compliance with the ozone standard.
DPR has agreed to reduce the amount of VOC emissions contributed by the use of pesticides in areas of non-attainment such as the San Joaquin Valley. The primary sources of pesticide VOCs are emulsifiable concentrate formulations and soil fumigants. DPR has enacted a set of regulations on the use of VOC-emitting pesticides, notably soil fumigants and emulsifiable concentrate (EC) pesticides that sets a cap on the total VOC emissions from all pesticides during the peak ozone period from May 1 to October 31 in the San Joaquin Valley. In addition, the rule severely restricts application methods, timing and volume of all commonly used soil fumigants. The new rules went into effect January 2008 and can be found on the DPR Web site.
The Almond Board of California (ABC) is participating with DPR, USDA-NRCS and UC Extension on a collaborative project to educate PCAs and growers on pest control options that reduce VOC emissions from pesticides used in nut and tree fruit orchards in the San Joaquin Valley. The project, funded by a grant from U.S. EPA, will focus on developing a VOC calculator, and outreach and education on VOC emissions. The project will also focus on techniques to reduce water contamination. In addition, ABC is funding research to reduce the off-gassing from soil fumigations and reduce the amount of soil fumigants needed.