High-global warming potential F-gas emissions in California: comparison of ambient-based versus inventory-based emission estimates, and implications of refined estimates.

To provide information for greenhouse gas reduction policies, the California Air Resources Board (CARB) inventories annual emissions of high-global-warming potential (GWP) fluorinated gases, the fastest growing sector of greenhouse gas (GHG) emissions globally. Baseline 2008 F-gas emissions estimates for selected chlorofluorocarbons (CFC-12), hydrochlorofluorocarbons (HCFC-22), and hydrofluorocarbons (HFC-134a) made with an inventory-based methodology were compared to emissions estimates made by ambient-based measurements. Significant discrepancies were found, with the inventory-based emissions methodology resulting in a systematic 42% under-estimation of CFC-12 emissions from older refrigeration equipment and older vehicles, and a systematic 114% overestimation of emissions for HFC-134a, a refrigerant substitute for phased-out CFCs. Initial, inventory-based estimates for all F-gas emissions had assumed that equipment is no longer in service once it reaches its average lifetime of use. Revised emission estimates using improved models for equipment age at end-of-life, inventories, and leak rates specific to California resulted in F-gas emissions estimates in closer agreement to ambient-based measurements. The discrepancies between inventory-based estimates and ambient-based measurements were reduced from -42% to -6% for CFC-12, and from +114% to +9% for HFC-134a.

Implementing safer alternatives to lithographic cleanup solvents to protect the health of workers and the environment.

The use of volatile organic compounds (VOCs) in lithographic printing cleanup is an environmental and occupational hazard. Regulations to reduce ambient ozone levels limited VOC emissions from lithographic cleanup operations and spurred the development of low-VOC alternatives. The purpose of this project was to promote the substitution of hazardous cleanup solvents with less toxic chemicals to protect the health of workers and the environment. A convenience sample of printers, employers, union, industry, and government representatives was constructed. Data regarding the lithographic printing work force and the use of cleanup solvents and alternatives were collected through: (1) work site walk-throughs, (2) a focus group, (3) key informant interviews, (4) a half-day workshop, and (5) demonstration projects. Overall, 66 individuals from 15 different print shops, 10 government agencies, the lithographic printing industry, and one printer's union participated in one or more aspects of the project. Printer inhalation exposure to hazardous cleanup solvents was prevalent and printers were not aware of safer alternatives. Employers should implement low-VOC, low-toxicity cleanup products in a timely manner to protect the health of printers and the environment. Use of low-VOC lithographic cleanup products does not mitigate the potential for printer dermal exposure and may carry safety and ergonomic implications. Lithographic cleanup solvent manufacturers should seek low-VOC ingredients that do not pose a dermal exposure hazard. Linking environmental and occupational health prevented the development of substitutes that would have introduced worker hazards and provided an opportunity to circumvent some of the inadequacies of the current occupational health regulatory apparatus. Governmental organizations should establish and maintain institutional interdisciplinary mechanisms to support these linkages.