Although tighter ozone regulations have been back-burnered for now, coatings makers aren’t taking any chances, continuing to muster data to build their case against tougher VOC limits.
The American Coatings Association has just released a study in support of its contention that regulators overstate the air-quality impact of Volatile Organic Compounds from industrial maintenance and architectural coatings.
|Regulation of VOC content in coatings has reduced VOC emissions, even as coatings usage has increased, ACA’s preliminary analysis found.|
“VOC content has become the primary indicator of environmental acceptability for coatings,” the coating manufacturers’ group writes in the Executive Overview of its Paints and Architectural Coatings Environmental Study (PACES). “This approach, however, has limitations.”
The research was funded totally by the coatings industry, aided by a “technical advisory committee” comprised of coating manufacturers, raw material suppliers, and representatives from the ACA, Environmental Protection Agency, California Air Resources Board, and South Coast Air Quality Management District.
ACA says it launched the study in 2006, to “gather scientific data needed to evaluate total environmental impacts of the regulatory trend toward increasingly stringent” VOC limits on coatings.
The study focused on the regulatory assumption that limiting VOC content on a mass basis reduces concentrations of ground-level ozone, a key component of smog.
ACA contends that the equation is not that simple. It argues that current regulations:
• Limit VOC content without considering “reactivity,” the variable ability of VOCs to promote accumulation of ground-level ozone;
• Assume that VOC content has full “atmospheric availability” for consumption in reactions that promote ozone, “while in reality some VOCs are only partially available”; and
• Do not consider coatings’ entire life cycle and should factor in a life-cycle analysis that also examines coating impact on water quality, energy and material consumption, solid waste disposal, and human health and safety.
Phase 1: Reductions Cited
The research unfolded in two phases.
In the first, ACA sought to develop models to measure ambient air concentrations of TPM (Trimethyl Pentanediol Monoisobutyrate), commonly known by its trade name of Texanol.
“Historical ‘micro level’ studies suggest that as much as 40% of TPM never evaporates from paint films, and is therefore not available for participation in ozone photochemistry,” the study said.
ACA says it developed analytical instrumentation and measurement protocols for TPM but could not measure “elevated TPM concentrations downwind of painting operations” due to movement of the downwind “plume.”
The association also looked at VOC content and emissions from the use of thinners, additives and cleanup solvents, but excluded disposal of waste paint and solvent from those calculations.
Nevertheless, the study conceded, “preliminary analysis” indicates that regulating architectural coating VOC content “appears to have decreased VOC emissions from such coatings over the last several decades,” even while use of those coatings “has increased significantly.”
Phase 2: Residuals and Emissions
In Phase 2, the team continued its ambient measurements of TPM in Southern California and attempted to measure the availability of TPM for purposes of ozone production.
Among those findings:
• About half of TPM “was ‘lost’ from the paint film” within 90 days of painting. Almost 90% of TPM was lost within six months. At 11 months, about 12% of the TPM remained.
ACA said it made “no attempt” to monitor air emissions during the 11-month period.
• Analysis of gypsum wallboard samples painted nine to 17 years earlier in California and Texas found that all “contained residual TPM” in concentrations ranging from 300 mg/m² to more than 2,000 mg/m².
The analysis “indicates that decades would be required to completely deplete the residual TPM, less any portion retained permanently,” the study found.
• An analysis of Ethylene Glycol and Propylene Glycol in latex paint found that emissions varied with the type of paint and substrate.
For example, the study reported, flat paint was found to produce higher emissions than semi-gloss, and stucco substrates more than gypsum wallboard.
The PACES project “has established a foundation for future research,” with the Phase II findings providing “a technical basis for future regulatory policies,” the study reported.
Those policies will surely include the long-running battle over ozone standards.
The Obama Administration announced in September that it was dropping its years-old plan to tighten ozone standards, but the issue has not gone away.
Environmental and public health advocates are still suing for tighter standards, saying the Administration of George W. Bush unlawfully ignored scientific recommendations in setting more lenient levels.
The study sees promise in future research into:
• Life cycle analysis of coatings;
• Improvement of the coating emissions inventory; and
• Development of more accurate air quality modeling of coating impacts under changing air shed conditions.