Low- and Zero-Emissions Zones

The document explores low- and zero-emissions zones (LEZs and ZEZs) as tools for cities to reduce air pollution and greenhouse gas emissions. It compares international examples from Europe and Singapore with a voluntary pilot in Santa Monica, California. A significant portion of the guide is dedicated to ensuring equity, arguing that ZEZs in California must be designed to avoid regressive financial burdens on low-income residents and people of color, who are disproportionately exposed to vehicle-related PM2.5 pollution. The authors recommend that California provide enabling legislation for cities to implement these zones and suggest targeting high-pollution sectors, such as heavy-duty freight, to maximize public health benefits in disadvantaged communities.

• Low-emissions zones (LEZs) and zero-emissions zones (ZEZs) differ from congestion zones in their primary goals; while congestion zones focus on reducing vehicle travel and traffic, LEZs and ZEZs are designed to reduce emissions to combat air pollution and meet global warming goals.
• International case studies show varying enforcement and outcomes: London uses an automated camera system (Automatic Number Plate Recognition) to manage three additive zones, resulting in a 44% reduction in roadside NO2 in the central ULEZ since February 2017. Paris utilizes visual police inspections of 'Crit’Air' stickers, with projections suggesting passenger car NOx emissions in 2024 will be 76% to 87% below 2016 levels due to its LEZ.
• In California, air pollution exposure is racially and economically inequitable; Black Californians are exposed to PM2.5 pollution that is 43% higher on average than White Californians, and Latino community members are exposed to 39% higher levels. The lowest-income households live where PM2.5 pollution is 10% higher than the state average.
• To ensure equity in California ZEZs, policymakers must address five key concerns: the lack of accessible education materials, the regressive nature of fees and fines for low-income residents, the need to prioritize the highest pollution sources (medium- and heavy-duty vehicles), the risk of over-policing and surveillance in marginalized communities, and the need for revenue to be reinvested into equitable mobility projects.
• Stakeholder interviews in California revealed significant concerns regarding the 'displacement' of pollution, where non-compliant vehicles might take alternate routes and increase pollution in peripheral disadvantaged communities, as well as a deep-seated mistrust of local government funding oversight.
• The authors recommend that California enact enabling legislation to allow cities to develop LEZs and suggest that these zones be paired with other strategies, such as incentives to scrap polluting vehicles and investments in public transit, to avoid harming car-dependent populations.

APA

Union of Concerned Scientists (2021). Low- and Zero-Emissions Zones. https://www.ucs.org/sites/default/files/2021-07/low-and-zero-emissions-zones.pdf

Chicago

Union of Concerned Scientists. Low- and Zero-Emissions Zones. 2021. https://www.ucs.org/sites/default/files/2021-07/low-and-zero-emissions-zones.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Low- and Zero-Emissions Zones |date=June 2021 |url=https://www.ucs.org/sites/default/files/2021-07/low-and-zero-emissions-zones.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientists2021low, author = {{Union of Concerned Scientists}}, title = {{Low- and Zero-Emissions Zones}}, institution = {Union of Concerned Scientists}, year = {2021}, month = jun, url = {https://www.ucs.org/sites/default/files/2021-07/low-and-zero-emissions-zones.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }