6.24 Industrial Commercial Coatings

Categories 1914-1933, 252, 253, 256-263, and 266-281

6.24.1 Introduction

The following categories contain the inventory of organic gas emissions (TOG and ROG) that result from the use of industrial coatings, special product coatings, and thinning and clean-up solvents:

  • Can and Coil (P - categories: 252-253)
  • Wood Furniture & Cabinet (P - categories: 256-257/A - categories: 1914-1915)
  • Paper Coating(P- categories: 258-259/A - categories: 1916-1917)
  • Fabric & Film (P - categories: 260-261/A - categories: 1918-1919)
  • Plastic Parts & Product (P - categories: 261-263/A - categories: 1920-1922)
  • Magnet Wire (P - categories: 264-265)
  • Large Appliance & Metal Furniture (P - categories: 266-267 /A - categories: 1924-1925)
  • Misc. Metal Parts & Small Appliance (P - categories: 268-269/A - categories: 1926-1927)
  • Flat Wood Paneling (P - categories: 270-271)
  • Motor Vehicle Assembly Plants (P - categories: 272-273)
  • Auto Refinishing (P - categories: 274-275/ A - categories: 1928-1929)
  • Marine Coating (P - categories: 276-277/A - categories: 1930-1931)
  • Aerospace Assembly (P - categories: 278-279)
  • Other Coatings (P - categories: 280-281/A - categories: 1932-1933)

Note: “P” signifies point source category. “A” signifies area source category. The categories with a “P/A” have both point and area source categories to encompass total emissions for the Bay Area.

These categories are composed of many types of coatings such as enamels, lacquers, varnishes, etc. Organic emissions occur from the evaporation of organic solvents, which result from the application and drying of coatings. In order to calculate emissions, the amount of coatings, the solvent fraction of the coatings, and the amount of thinning and cleanup solvent, should be known. The efficiency of control equipment, such as afterburners, condensers, and the amount of solvent recycled are all useful variables in determining emissions.

6.24.2 Methodology

Point Sources

Point Sources are operations that emit air pollution into the atmosphere at a fixed location within a facility, for which the Air District has issued a permit to operate, e.g., refinery cooling towers. These could also be a collection of similar equipment / sources located across multiple facilities, e.g., reciprocating engines.

During the permit to operate (PTO) issuance process, the BAAQMD collects information from the operating facility and/or determines from published literature, e.g., EPA’s AP-42, characteristics of a source including maximum throughput, emission factors for emitted pollutants, and control factors associated with downstream abatement devices. These characteristics are then stored for future use in the BAAQMD’s internal database. Facilities that hold a permit to operate are required to renew this permit periodically (this period varies based on facility and source type). Upon renewal, the facilities are requested to provide any updates to source characteristics as well as the source throughput for the last 12 months. This throughput, in combination with the emission factors and controls factors stored in the internal database, are used to estimate annual emissions at the source level. These source level emissions are then sorted and aggregated into categories.

Categories 252, 253, 256-263, 266-281 are considered point source categories and follow the above methodology for emissions estimates.

Area Sources

Categories 1914 through 1933 are considered an area source category as they cover smaller, retail bakeries that are not explicitly permitted or individually cataloged by the District. Emissions for area source categories are determined using the formula:

Current Year Emissions = Base Year Emission X Growth Profile, and,

Base Year Emission = Throughput X Control Factor X Emission Factor

where,

  • throughput or activity data for applicable base year(s) is determined using a top-down approach (e.g. state-, national-level data);
  • emission factor is derived from general literature, specific literature and reports, and/or source testing results provided by Air District staff;
  • control factor (if applicable) is determined by District and state rules and regulations in effect;
  • and, historical backcasting and forecasting of emissions is based on growth profiles as outlined in the Trends section of this chapter

The method for determining emissions for associated area source categories are as follows:

  • For Wood Furniture and Cabinet Coating categories (Cat. 1914-1915), the total number of facilities under this category were determined from the latest County Business Pattern Count (n_business_total). From this total number, those businesses already accounted for under point source categories 256 and 257 were negated to obtain the total number of area source businesses (n_business_area = n_business_total - n_business_pt). This total area source business number in combination with the average emission factor per business for coating and cleanup, respectively, as determined from the associated point source categories (pt_emf), was used to calculate emissions (n_business_area * pt_emf).

  • For Paper, Fabric and Film Coating categories (Cat. 1916-1919), Misc. Metal Parts and Small Appliance categories (Cat. 1926-1927), and Other Coating categories (Cat. 1932-1933), it was assumed that the majority sources were permitted and therefore accounted for under point source categories. However, due to exemptions and non-compliance with District regulations, a small portion may not be covered. For each of these coating/cleanup pairs, an approximate percentage of exempt and non-compliant sources was determined and applied to point source emissions to estimate area source emissions (area_ems = %non_compliance_and_exempt * pt_ems). The percentage applied to each pair is outlined below:

    • Paper, Fabric and Film Coating categories (Cat. 1916-1919): 10%
    • Misc. Metal Parts and Small Appliance categories (Cat. 1926-1927): 10%
    • Auto Refinishing Coating categories (Cat. 1928,1929): 33% (1/3)
    • Other Coating categories (Cat. 1932-1933): 20%

  • Magnetic Wire Coating area source categories 1922-1923, have been removed from the inventory as the probability of a magnetic wire coating facility/operation operating without a permit, i.e. not being a point source, is very low. Therefore all existing operations are assumed to fall within the point source associated categories for coating and cleanup, categories 264 and 265, and an area source category is no longer needed.

  • Plastic Parts and Product Coating categories (Cat 1920 - 1921), Large Appliance and Metal Furniture Coating categories (Cat 1924-1925), and Marine Coating categories (Cat 1930-1931) all follow a similar method for determining emissions. Throughput is gathered from the Census Bureau report on the distribution of paints and allied products by sector 258. The proportion of this throughput for the SF Bay Area is then determined using the ratio of total employees in the associated sector in the US to that of the total employee count for the counties within the District’s jurisdiction. However, information concerning the distribution for paints is only available up until year 2010. Therefore the throughput for each of these categories must be projected forward to estimate emissions for subsequent years, including the base year(s) for this inventory. For each of these coating and cleanup category pairs, the basis of the projection is outlined below:

    • For Plastic Parts and Product Coatings (Cat 1920 - 1921), usage for later years is based on actual volumes of the U.S. Industrial Original Equipment Manufacturer (OEM) Coatings as gathered from the American Coatings Assocation259.

    • For Large Appliance and Metal Furniture Coating (Cat 1924-1925), usage for later years is based on information on the growth of the USA appliance coating market as gathered from the “USA Appliance Coatings Market Report 2019” by Market Intellica.

    • For Marine Coating (Cat 1930-1931), usage for later years is based on information on the growth of U.S. Marine Coatings Market through 2024 as gathered from the Coatings World website 260.

As mentioned previously, this extrapolated throughput was then multiplied by the percent of businesses located in the Bay Area (also determined via Census Bureau data) and the average emissions per business (pt_emf, as determined from associate point source data) to obtain the estimated emissions for the category (n_business_usa * % sfba_businesses * pt_emf).

The ROG/TOG ratios applied to this category or this group of related categories are based on an Air District internal speciation profile. Multiple data sources have been used for developing speciation profiles, such as Air District-approved source tests, TOG speciation ratios used by other regional air quality agencies, and relevant literature including latest speciation profiles developed by CARB261 and the US Environmental Protection Agency262. For categories associated with coating, ROG constitutes 98% of TOG.For categories associated with clean up, ROG constitutes 80% of TOG. Further assessment and improvement of ROG/ TOG speciation profiles has been planned in future inventory updates.

County Distribution

Solvent emissions for the Bay Area were apportioned into counties by one of the methods listed below for each industrial coatings category:

  1. The county location of each company as reported in the District’s permit database,
  2. Employee (for a given industry) population distribution,
  3. Establishment (for a given industry) population distribution, or
  4. Total population distribution

For those categories where method 1 was chosen, it is assumed that the internal District database accounts for the majority of the emissions within the category and therefore is a more accurate estimate for county dispersion than the other methods noted. In addition, for categories that use method one, the county fractions between category pairs (clean up and coating) may differ due to the use of emissions and usage data that is specific to each process respectively.

6.24.3 Changes in Methodology

For Wood Furniture and Cabinet Coating area source categories 1914-1915, a slightly different method for estimating business that fall under this category was used for this base year inventory. Previous to this inventory, it was assumed that all businesses in a particular NAICS used coatings and are subject to District rules, but this was an over-estimate. New weighting factors by NAICS were implemented in this inventory to adjust for this over-estimate.

For Plastic Parts and Product Coating area source categories 1920-1921, prior base year estimated emissions were based on an 1987 assumed proportion of total paints distributed. This proportion is out of date and industry has greatly changed since the 1980s. Instead of using this proportion, throughput is based on more recent Census Bureau information and extrapolated to the base year using an appropriate growth statistic as noted in the previous section.

For Auto Refinishing area source categories 1928-1929, prior inventory estimated emissions were based on a proportion of emissions from a California Air Resource Board 2001 survey. This data is now out of date and most businesses should be permitted. Thus area source emissions should be a fraction of point source emissions. Therefore, this base year inventory estimates were made assuming area source emissions are roughly 20% of permitted emissions.

The area source portion of Magnet Wire Coating is considered negligible and is not presented in this base year.

6.24.4 Emissions

A summary of emissions by category, county, and year are available via the associated data dashboard for this inventory publication.

6.24.6 Uncertainties

There is uncertainty in the assumed percentage of non-compliant and exempt sources used when estimating some area source category emissions. Refinement of these percentages are slated as future improvements to the inventory.

6.24.7 Contact

Author: Ariana Husain

Reviewer: Sukarn Claire

Last Update: November 06, 2023

6.24.8 References & Footnotes

  1. U.S. Census Bureau. MA325F - Paints and Allied Products. [accessed 2023 Mar 3]. https://www.census.gov/data/tables/time-series/econ/cir/ma325f.2009.html#list-tab-4XOBXPZXWG8RT7QW69↩︎

  2. CoatingsTech. 2018. Nine Years Following the Great Recession;The Stat of the U.S. Paint and Coatings Industry. https://www.paint.org/coatingstech-magazine/articles/nine-years-following-great-recession-state-u-s-paint-coatings-industry/↩︎

  3. CoatingsWorld. 2017. Marine Coatings Market Estimated to Exceed $15 billion by end of 2024.https://www.coatingsworld.com/contents/view_breaking-news/2017-03-01/marine-coating-market-estimated-to-exceed-15-billion-by-end-of-2024/↩︎

  4. ORGPROF. CARB 2022. https://ww2.arb.ca.gov/speciation-profiles-used-carb-modeling↩︎

  5. SPECIATE. USEPA 2022. https://www.epa.gov/air-emissions-modeling/speciate↩︎

  6. Association of Bay Area Governments (ABAG). Forecasts and Projections. [accessed 2023 Feb 22]. https://abag.ca.gov/our-work/land-use/forecasts-projections↩︎