Article Published in Science Journal Presents Flawed Data Regarding VOC Emissions from Architectural Coatings
February 23, 2018 – The American Coatings Association (ACA)1 and members of the coatings industry find that the data and conclusions presented in the research article “Volatile Chemical Products Emerging as Largest Petrochemical Source of Urban Organic Emissions,” recently published in the journal Science, are deeply flawed with respect to architectural coatings (paints and coatings applied to buildings and other stationary structures).
While the authors recognized and accounted for transportation-related (motor vehicle) VOC emission reductions, they do not recognize or account for similar and significant VOC reductions in architectural coatings achieved through regulatory compliance and industry innovations. Regulations limiting the VOC content of architectural coatings were first adopted in Southern California in 1977, taking effect in 1978. During the 40 years since then, the South Coast Air Quality Management District (SCAQMD) has amended its Rule 1113 (Architectural Coatings) 30 times, drastically lowering VOC limits for paint and coatings, and colorants used to tint them.
The California Air Resources Board conducts periodic surveys of architectural coatings distributed in California. The latest published survey, covering architectural coatings distributed in 2005, contains data showing that the average actual VOC content of architectural coatings was 0.63 pound per gallon. Given the average weight per gallon as 10.5 pounds, we calculate that architectural coatings contained (on average) 6 percent organic solvent by weight.
And yet, the Supplementary Materials for the article identify the organic solvent content of architectural coatings (on page 25, Table S4) as 0.49 gram organic solvent per gram of coating, which is to say, 49 percent organic solvent by weight. This overstates the VOC content of architectural coatings by a factor of 8. Moreover, the SCAQMD, which collects data on architectural coatings sold in the District annually, has determined that VOC emissions from architectural coatings have decreased by 50 percent between 2008 and 2016. This reduces the average VOC content of architectural coatings to 3 percent organic solvent by weight – and expands the article’s degree of overstatement to a factor of 16.
Consequently, we believe that this gross overstatement of VOC content in architectural coatings invalidates the article’s conclusions and recommendations with respect to VOC emissions from architectural coatings. We also question whether the article’s estimates of VOC content in adhesives and other consumer products are anywhere near accurate, if the methodology used to develop those estimates was the same as that used for architectural coatings.
1 The American Coatings Association (ACA) is a voluntary, nonprofit trade association representing paint and coatings manufacturers, raw materials suppliers, distributors, and technical professionals. ACA serves as an advocate and ally for members on legislative, regulatory, and judicial matters.
architectural coatings. We also question whether the article’s estimates of VOC content in adhesives and other consumer products are anywhere near accurate, if the methodology used to develop those estimates was the same as that used for architectural coatings