AIR TOPICS: Mobile Sources

AIR TOPICS: Mobile Sources

Please visit our Policy Resource Kit page to find out about current actions related to Mobile Sourcesin your region

Mobile Sources Overview

Mobile source air pollution comes from on-road vehicles (such as cars, trucks, buses and recreational vehicles) as well as non-road vehicles (such as aircraft, marine vessels, construction equipment, and power tools). Emissions from these sources contribute to particulate matter (PM), greenhouse gases, air toxics, and the creation of ground level ozone when nitrogen oxides (NOx) and volatile organic compounds (VOC) chemically react in the presence of sunlight.

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EPA’s Reconsideration of the Withdrawal of California’s Waiver for the Advanced Clean Car Program (SAFE-1)

The EPA is reconsidering the previous administration’s SAFE Vehicles Rule (background information and NTAA’s comments can be found below). The EPA has broken this reconsideration into two parts: 1) SAFE-1, which includes interpretations that led to the withdrawal of the California waiver, and 2) SAFE-2, which will address the fuel efficiency standards (and is expected to be proposed in July 2021). The deadline for commenting on SAFE-1 is July 6, 2021, and a full Policy Resource Kit will be posted here and to the PRK page on this site. More information on this proposal and how to comment can be found here.

Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule

In October 2018, the NTAA commented on the previous administration’s SAFE Vehicles proposal. The National Highway Traffic Safety Administration (NHTSA) and the Environmental Protection Agency (EPA) had proposed to amend certain existing Corporate Average Fuel Economy (CAFE) and greenhouse gas emissions standards for passenger cars and light trucks and establish new standards, covering model years 2021 through 2026. NTAA called the new standards a setback for air quality and environmental policy, and said they overlook the adverse impact on Tribal health and the environment from the air pollution and greenhouse gas emissions from cars and light trucks.

Air Permits for Gas Stations on Tribal Lands

On May 1, 2019, EPA Region 9 issued a final General Permit under the Clean Air Act Tribal Minor New Source Review program at 49.151 through 49.161 (Tribal Minor NSR program). This General Permit is available for gasoline dispensing facilities (GDFs), such as gas stations, located in Indian country within the geographical boundaries of California. 

For information on GDFs in Indian country outside of California:
EPA: 5 Source Categories – Gasoline Dispensing Facilities (Final Rule)


Cruise Ships

There are more than 230 cruise ships operating world wide. Cruise ships are akin to floating cities, providing many of the same services that small cities or towns provide to their citizens. These vessels can carry as many as 3,000 passengers and crew members, and often operate in coastal waters near Tribal lands. As the cruise ship industry continues to expand, there is an increasing concern about the environmental impacts of cruise ship discharges.

EPA: Cruise Ship Discharges and Studies


Lead Emissions from Aircraft

Piston-engine aircraft operating on leaded aviation gasoline are the largest remaining aggregate source of lead emissions to air in the US. The EPA is evaluating the air quality impact of lead emissions from aircraft using leaded aviation gasoline as described in the Federal Lead Action Plan to Reduce Childhood Lead Exposures and Associated Health Impacts and in response to petitioners’ requests.


On October 14, 2020, NTAA submitted a letter to the U.S. Department of Justice (DOJ) to comment on the Proposed Consent Decree Between the United States Environmental Protection Agency, the California Air Resources Board and Daimler to Settle Complaint for Civil Penalties and Injunctive Relief for Violations of the Clean Air Act, Civil Action No.: 1:20-cv-2564 (D. D.C). NTAA’s comments urge better Tribal consultation by DOJ to provide better mitigation actions as part of the settlement. You can find the consent decree here. California’s Air Resources Board has filed a separate consent decree that applies only in California that can be found here.

On May 7, 2020, the NTAA Mobile Sources Work Group hosted representatives from the EPA to present an overview of information on diesel fuels and engines. The recordings of the presentations can be accessed below. The “Fuels” presentation is on the left, and the “Engines” presentation is on the right.

NTAA Letter to EPA with Recommendations on Tribal DERA Program – On January 10, 2020, the NTAA EC and Mobile Sources Work Group submitted this letter to the EPA to provide recommendations on how to improve the Tribal Diesel Emissions Reductions Act (Tribal DERA) program so that it is more fully utilized, better meets the goals of the program, and better serves Indian Country.

Latest Webinar:

Mobile Sources Resources

NTAA Webinar Workshop for Tribes on EPA’s Clean School Bus Program

This virtual workshop was held on August 4th in lieu of NTAA’s Mobile Sources Work Group monthly call. This workshop will help Tribes learn how to access EPA’s $5 Billion investment for the Clean School Bus Program (CSBP). For the next 5 years, Tribes and Tribal Schools are prioritized for funding new electric and cleaner school buses. Applications for the first year of funding closes on August 19th!

NTAA was honored to have Congresswoman Katie Porter and EPA OAR Deputy Assistant Administrator, Alejandra Nunez! The recording from the webinar is now available on NTAA’s website!
The Future of Transportation

On April 1, the NTAA Mobile Sources Work Group heard a presentation from EPA on the Future of Transportation: Upcoming Legislation. You can access the presentation, which contains links and resources, by clicking the link.

Volkswagen Program

In 2015 Volkswagen was cited by EPA and the California Air Resources Board for violating emissions standards by selling diesel vehicles equipped devices that allowed the cars to cheat at federal emissions tests. The federal government sued and in 2016 VW settled the cases for $14.7 billion. Of that, $55 million was set aside for federally recognized Tribes which they can use to replace old, polluting diesel vehicles or equipment with new, cleaner models, or even install electric vehicle charging stations.

The Institute for Tribal Environmental Professionals (ITEP) was named as the Technical Assistance Provider. ITEP supports Tribes with webinars and other training resources, as well as one-on-one assistance with navigating the process of applying for and receiving funds from the settlement.

NTAA was integral in securing the Tribal Trust Agreement, establishing the technical assistance program, and ensuring the development of the Tribal Advisory Council.

ITEP: Technical Assistance Program to Access the VW Settlement

ITEP: Tribal Advisory Council

Alternative Fuels

The Columbia-Willamette Clean Cities group gave a presentation on Alternative Fuels Solutions to NTAA’s Mobile Sources Working Group at its October 2019 meeting. The presentation goes through the various alternative fuels currently available and describes what types of vehicles & equipment can run on each, along with pros and cons of each option. The presentation emphasizes ways in which alternative fuel vehicles can provide environmental and performance benefits for vehicle fleets, while often reducing maintenance needs and operating costs. This presentation can be a useful resource for Tribes considering purchasing alternative-fuel vehicles with their VW Settlement funds.

Columbia-Willamette Clean Cities Coalition: Presentation on Alternative Fuels

EPA Resources

The mission of EPA’s Office of Transportation and Air Quality (OTAQ) is to protect human health and the environment by reducing air pollution and greenhouse gas emissions from mobile sources and the fuels that power them, advancing clean fuels and technology, and encouraging business practices and travel choices that minimize emissions. OTAQ’s programs address emissions from the range of mobile sources: cars and light trucks, large trucks and buses, farm and construction equipment, lawn and garden equipment, marine engines, aircraft, and locomotives.

Funding Opportunities

NTAA continues to seek out funding opportunities for Tribes to help them develop policies and actions related to Mobile Sources. Please check back as this list may be updated frequently.

EPAs Office of Transportation and Air Quality solicits applications nationwide for Tribal projects that achieve significant reductions in diesel emissions and diesel emissions exposure, particularly from fleets located in areas designated as having poor air quality. In 2019, EPA awarded $4 million to eligible Tribal applicants. 

EPA: Clean Diesel Tribal Grants

ITEP: Technical Assistance Program to Access the VW Settlement

ITEP: Tribal Advisory Council

Mobile Sources Work Group

The Mobile Sources Work Group was formed to address pollution and emissions issues stemming from transportation and other mobile sources.


The Mobile Sources Work Group hosts monthly calls for Tribes on the 1st Thursday of each month at 2 pm ET.

Check NTAA’s calendar or NTAA’s Weekly Update to find out when these meetings take place and how to participate.

Get the latest notifications, agendas, and relevant documents by subscribing to NTAA and becoming a member.

Mobile Sources Work Group Leads: Craig Kreman, Region 6 NTAA EC Member ( and Ryan Tsingine, NTAA Research Assistant (