
Statewide Mobile Monitoring Initiative (SMMI)
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Project Updates as of June 30, 2025
Following a comprehensive review of the 62 SMMI Community Air Monitoring Plans (CAMPs) and upon conclusion of a 14-day public and internal comment period, CARB is granting approval of specific broad area monitoring components in each of the 62 CAMPs. The following sections of each of the 62 CAMPs are approved and may proceed as proposed (revisions may be made to improve clarity or grammar; however, the substantive content will remain unchanged; appendices are not included in this approval):
- Section 7.1 “Monitoring equipment” (only the language that pertains to Aclima broad area monitoring equipment)
- Section 7.2 “Monitoring methods – broad area monitoring“
- Section 8.2 “Broad Area Monitoring Coverage”
- Section 9.1 “Aclima’s Quality Assurance and Quality Control Procedures”
- Section 10 “Data management” (only the language that pertains to Aclima broad area monitoring)
- Section 11.1 “Broad area monitoring”
Several components of the plan, specifically those involving targeted area monitoring and the interpretation of results, remain unapproved and are currently undergoing revisions in response to feedback received during the initial review process and internal assessment. The sections noted above are approved; however, monitoring based on unapproved portions of the CAMPs may not proceed until these portions have undergone an additional review cycle and received approval from CARB.
Next Steps:
Six revised CAMPs addressing the unapproved components will be released for a second public comment period from July 1 until July 17 on Aclima's SMMI website. These CAMPs serve as a representative subset, selected based on geographic distribution, land-use types, and the range of pollutants to be monitored, to allow stakeholders to provide input on the updated material prior to further CAMP approvals. Comments received on the representative CAMPs will be considered applicable to other CAMPs.
Project Introduction
The Statewide Mobile Monitoring Initiative (SMMI) is designed to attain a comprehensive dataset of criteria pollutants, toxic air contaminants, and greenhouse gases, create a data portal for public to access and visualize SMMI data, and conduct inclusive community engagement to better understand and address community concerns. This project provides an opportunity to complement AB 617 statewide air monitoring activities by engaging communities beyond those currently selected under the Community Air Protection Program, providing data to fill air monitoring gaps and support additional actions to reduce emissions and exposure. Read the September 2024 project press release and June 2025 launch of monitoring press release, or watch the video below to learn more.
Project Background
CARB received $27 million through legislative appropriation to conduct mobile air monitoring in communities across the state. CARB awarded a $26.88 million contract to Aclima, a California Public Benefit Corporation that specializes in hyperlocal air quality mapping and analysis, through a competitive solicitation process called a Request for Proposals (RFP). The RFP was released on January 22, 2024 to solicitate proposals to carry out primary tasks, such as community engagement, mobile monitoring, data management, and data analysis and visualization. CARB selected Aclima pursuant to its capability and capacity to carry out the primary tasks. The contract was approved on June 14, 2024.
An air quality concerns survey remains active through the project to continue collecting information (e.g., air pollution concerns, pollutant types and sources, and locations in the communities) from the public to help us better prepare for mobile monitoring.
Project Summary
We provide a brief summary below. Please review the One-pager, Frequently Asked Questions (FAQ) document, and Aclima's technical proposal (also available in the "Documents" section below) if you’d like to have a deeper dive into this project.
Aclima and their subcontractors will conduct mobile monitoring of criteria pollutants, greenhouse gases, and toxic air contaminants in Community Air Protection Program (CAPP) Consistently Nominated AB 617 Communities (CNCs) using a combination of 42 Aclima mobile platforms and 3 partner mobile laboratories (operated by UC Berkeley, UC Riverside, and Aerodyne).
The project held a virtual public kick-off meeting on September 17, 2024 and a Project Expert Group (PEG) has been formed to guide SMMI throughout the project period. The PEG partnered with Aclima to co-develop a community engagement plan (CEP) and community air monitoring plans (CAMPs). These documents guide engagement and monitoring activities and ensure objectives align with community needs and goals. Specific monitoring areas will be determined through a community engagement process and documented in CAMPs. At least 60% of monitoring must be conducted to benefit California Climate Investments priority populations.
Mobile monitoring will begin with a broad area monitoring strategy, through which Aclima’s fleet of Mobile Platforms will collect data within each community boundary, gathering repeat measurements at different times of day, days of the week, and seasons across 9 months. Aclima and its research partners (partner mobile laboratories including UC Berkeley, UC Riverside, and Aerodyne) will also conduct targeted area monitoring that focuses on specific air pollution concerns at smaller spatial scales. This involves monitoring over a relatively small area over a shorter duration in time in each community (approximately 1 to 2 weeks) and is designed to complement the broad area monitoring coverage by providing more in-depth information about a specific area of concern. Aclima platforms measure criteria pollutants and surrogates for air toxic contaminants; partner mobile laboratories are capable of speciation analysis of air contaminants (e.g., benzene and formaldehyde). Mobile monitoring is designed to capture representative air pollutants in each community to achieve monitoring objectives defined in the CAMPs. At the end of the project, communities and the public will have access to a final data portal to understand and leverage the measurements (e.g., identification of sources of concern and natural gas leaks) to reduce air pollution in communities.
The Statewide Mobile Monitoring Initiative is part of California Climate Investments, a statewide initiative that puts billions of Cap-and-Trade dollars to work reducing greenhouse gas emissions, strengthening the economy, and improving public health and the environment — particularly in disadvantaged communities.
For more information please contact: smmi@arb.ca.gov
CAMPs now available!
Community Air Monitoring Plans (CAMPs) are live on Aclima's SMMI website.