Bay Area Low-Carbon Concrete Codes Project

Community Development Agency

Through a grant from the Bay Area Air Quality Management District, and in partnership with stakeholders from across the region, the County of Marin has developed proposed standards around practical requirements for the composition of concrete that maintains adequate strength and durability for the intended application and at the same time reduces greenhouse gas emissions associated with concrete composition. This code includes pathways for compliance with either reduced cement levels or lower-emission supplementary cementitious materials.

These materials will be considered for adoption by the Board of Supervisors in November 2019, and are available for public review and comment.

Project Documents (updated 10/20/2019)

The following documents are draft versions of code and specification language the County is currently seeking comment on. Please email Alice Zanmiller to provide comment or look for the comment docket.

Supporting Documents

Program Overview

In 2018, the County of Marin was granted funds from the Bay Area Air Quality Management District (BAAQMD)'s Climate Protection Grant Program. This project aims to reduce embodied emissions in the built environment by creating local specifications and model policies for low embodied-carbon concrete, developed through a robust regional stakeholder engagement process. The County of Marin leads the project, working in close partnership with StopWaste (Alameda County), Bruce King, Arup, and the Carbon Leadership Forum. The project proposal submitted to and funded by BAAQMD was supported by the City and County of San Francisco, County of Alameda, City of Berkeley, USGBC, and over 30 building industry companies and organizations that work in the Bay Area.

The opinions, findings, conclusions, and recommendations are those of the author and do no necessarily represent the views of the District. The District, its officers, employees, contractors, and subcontractors make no warranty, expressed or implied, and assume no legal liability for the information in this report.


In addition to the generous grant from the Bay Area Air Quality Management District (BAAQMD)'s Climate Protection Grant Program, a number of individuals who contributed to the effort as part of a committee that met between November of 2018 and July of 2019. Asterisk denotes members of the central project team.


  • Kate Simonen*, University of Washington and Carbon Leadership Forum
  • Mark Aschheim, Santa Clara University
  • Guarav Sant, UCLA
  • Wil Srubar, Colorado University, Boulder


  • Miya Kitahara*, StopWaste
  • Alice Zanmiller*, County of Marin
  • Karen Cook, Alameda County
  • Bill Kelley, County of Marin
  • Eden Brukman, City & County of San Francisco
  • Sarah Moore, City of Berkeley

Concrete Industry

  • Alana Guzzetta, Central Concrete/Us Concrete
  • Tien Peng, National Ready Mix Concrete Association
  • Hernan Jose Perez, Cemex

Engineers & Architects

  • Kimberly Loscher, Skanska
  • Eric Peterson, Webcor
  • Ryan Bell, University of California Office of the President
  • Bruce King, Ecological Building Network*
  • Frances Yang, Arup*


  • Wes Sullen, US Green Building Council

In addition to those listed above, we are grateful for the early review and comments by other interested stakeholders including those from Central Concrete, Climate Earth, Lehigh NW Cement Company, California-Nevada Cement Association, Sierra Club, StopWaste and more.

Finally, circumstances compel the project team, with support of the Concrete Working Group, to dedicate this body of work to Professor Mark Aschheim. Mark passed away before this code was completed, but was an active participant early in the project, and made many important contributions to it through his illness. He was widely known in the concrete industry for his contributions to seismic design, and widely known more broadly for his many contributions to climate-friendly construction in California, in Haiti, and all over the world. He was a good friend to many of us, and a teacher to many more. We offer our regards to his family, and this dedication to his memory.

What Are "Embodied Emissions"?

Embodied (or embedded) emissions are emissions of carbon dioxide or other greenhouse gases generated by making and transporting materials to a building site, including mining, refining, and shipping. Cement use in concrete is the largest single material source of embodied emissions in buildings, and makes for an estimated 8% of global emissions. Replacing cement with currently available alternative cementitious materials, such as fly ash or slag, and other practices to "decarbonize" concrete has the potential of reducing total emissions from concrete by more than half.

Read more about low-carbon concrete at Architecture 2030.

Learn more about embodied carbon through the Embodied Carbon Network, an international network of over 250 members.

Program Goal and Target Outcomes

The goal of the project is to reduce the carbon emissions embodied in building materials, starting with concrete, through modifications to building standards locally. There are four key outcomes identified in the work plan:

  1. Model code language for adoption by local governments. County of Marin staff will bring this language to the Board of Supervisors as part of 2019 Title 24 updates in the fall of 2019.
  2. Low embodied-carbon concrete specifications for residential and non-residential applications.
  3. Four pilot projects receiving technical assistance to apply the specifications by 2022.
  4. Formation of a Bay Area Concrete Working Group as an extension of the Embodied Carbon Network.


Background Documents


Project Updates

Interested in receiving updated about the County's Low Carbon Concrete Codes Project? Email Alice Zanmiller to be added to our mailing list.


Questions? Feedback?

Please contact Alice Zanmiller, Planner, at or (415) 473-2797