3.1 Coatings & Inks
Category 23
3.1.1 Introduction
Categories 23 accounts for organic emissions from the manufacturing of coatings and inks.
Coatings processes includes mixes, blends, or compounding of paints, varnishes, lacquers, enamels, shellac, or sealers from raw materials. Ink manufacturing involves mixes, blends or compounding other raw materials to produce the ink. Printing inks consist of pigments, which produce the desired colors, binders which lock the pigment to the substrate, and solvents, usually organic compounds that dissolve the pigments and binders. A majority of the emissions originate from mixing and cleaning operations.
3.1.2 Methodology
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.
Further speciation and quality assurance of emissions are performed as a part of the inventory process. The BAAQMD staff also perform a systematic crosswalk between CEPAM’s source category classification (Emission Inventory Code - EICs) and the District’s source category classification (category identification number - cat_ids), which ensures consistency in the annual emissions reporting process (CEIDARS) to California Air Resources Board. The last part of the inventory development process includes forecasting and back casting, and aggregation into sub-sectors and sectors for documentation purposes. For those years where no data is available, emissions data are backcasted to year-1990, as well as forecasted to year-2040 using either interpolation or another mathematical approach (see Trends section). Finally, emissions trends spanning from year 1990-2040 for each category and pollutant are evaluated for anomalies that are then investigated and addressed. Coatings and inks manufacturing category is considered a point source category and follows the above methodology for emissions estimates.
District Regulation 8, Rule 35 titled “Coating Ink and Adhesive Manufacturing” limits emissions from affected facilities permitted by the District under this category. The District adopted Regulation 8, Rule 35 10. The purpose of this rule is to reduce emissions of organic compounds from the manufacture of coatings, inks, and adhesives via controls on fugitive emissions through both containment and raw material changes e.g. using waterbase coating over organic based coating that produces less organic emissions.
3.1.3 Changes in Methodology
There are no changes in methodology to the current base year inventory approach as compared to the previous base year emissions methodology.
3.1.4 Emissions
A summary of emissions by category, county, and year are available via the associated data dashboard for this inventory publication.
3.1.5 Trends
The trend in decreasing emission is mainly a result of Rule 8-35 and its subsequent amendments. The rule was originally adopted by the District in 1984 and applied to large ink and coating facilities that utilize mixing vats greater than 45 liters in their processes, starting with the requirement of an emission control system applied to mixing processes. The rule was subsequently amended effective January 1993, to eliminate the exemptions for small users (having vats less than 45 liters). The amendment required lids on all portable and stationary mixing vats, and other cleaning provisions. Control effectiveness of the amended regulation has resulted in emission reduction greater than 50% since 1993.
(a) Historical Emissions / History
Historical emissions are derived from source-specific throughputs provided by the permitted facility, compiled/reported emission factors, and regulation-based control factors. This information is archived in the BAAQMD’s internal database which is queried to retrieve the data for historical and current years. Interpolation techniques to account for missing data are used when necessary, this is the case for years 1991-1992.
Emissions have been generally increasing due to increasing demand on coatings and inks. Even with the increase in activity and as previously mentioned, District [Rule 8-35], pertaining to emissions control from mixing operations at coating and ink facilities have regulated significant changes in the manufacturing process and thereby effectively reducing the emissions from these processes when compared to emissions prior to year 1984 before the enactment of the rule.
(b) Future Projections / Growth
Forecasting of point source emissions is done based on calculations as shown in the equation below using recently updated growth profiles and a base year of 2020. The growth profiles for the current base year inventory have been verified and updated to represent the most likely surrogate for growing emissions for a given category up to year 2040. Forecasting for point source emissions includes impact of in-place regulations, but does not include estimation of controls that will theoretically be implemented as part of future policy emission targets or proposed regulation and legislation.
\[ \text{PE} = \text{Gr} * \text{Ci} * \text{Ei} \] \(PE\) = projected emissions of pollutant i in a past or future year
\(Gr\) = growth rate by economic profile of industry or population
\(Ci\) = control factor of pollutant i based on adopted rules and regulations
\(PE\) = projected emissions of pollutant i in a future year
Projections from year 2020 to year 2040 was based on growth profile of ARB’s Manufacturing in the Printing Industry, and is expected to grow only at a 1-2 percent per year.
3.1.6 Uncertainties
Throughputs for this category are reported by facility via permit system requirement on a year by year basis and are assumed to reflect the most current data available at the time. Throughput data that are taken based on source test is considered the most accurate, followed by engineering calculations such as mass/material balance, and then published data via literature such as EPA AP-42. The emission factor is estimated using historical data and could change or be improved as new data is published.
3.1.7 Contact
Author: Tan Dinh
Reviewer: Abhinav Guha, Yuan Du
Last Update: November 06, 2023