More than 1.8 million Santa Clara County residents are breathing air that is making them sick. Children in East San Jose develop asthma at alarming rates. Seniors and people of color living near highways face the worst of it every single day. The county has failed its air quality assessments every year since 2016, ozone days are trending upward, and the Santa Clara Valley consistently ranks as the most polluted region in the entire Bay Area district, worse even than the refinery-heavy North Bay. It is a policy failure, and it has been building for years.
The Policy That Isn't Working: Spare the Air
The centerpiece of the Bay Area's air quality response is Spare the Air, a program that on bad air days asks residents to drive less, avoid barbecuing, and cut back on gas-powered lawn equipment. There is no enforcement mechanism for vehicles or binding consequences for the millions of single-occupancy cars idling on Highway 101 during a high-ozone afternoon. Surveys show that while more than 75% of Bay Area residents are aware of the program, fewer than 4% of drivers meaningfully change their behavior on alert days. A UC Berkeley researcher calculated the cost per ton of pollution removed through Spare the Air at $100,000 for nitrogen oxide and hydrocarbons, and $10 million per ton for particulate matter. Dedicated pollution reduction programs, by comparison, run about $5,000 and $20,000 per ton respectively. The BAAQMD's own spokesperson has said publicly that traffic congestion and the volume of single-occupancy vehicles on Bay Area roads "continues to impede our progress" on ozone and greenhouse gases. The agency running Spare the Air is admitting, in plain language, that Spare the Air is not working.
The COVID pandemic offered an unintentional proof of concept. When traffic in San Jose dropped by 70% in 2020, the BAAQMD recorded a 20% reduction in PM2.5 and a 40% drop in nitrogen oxides. The path to cleaner air in this city is not complicated. What is missing is a policy that can enforce authority onto the citizens.
What's Working Elsewhere: London's Low Emission Zones
London was dealing with a version of the same problem a decade and a half ago. Beginning with a Low Emission Zone in 2008 and expanding into the Ultra Low Emission Zone in 2019, London required drivers of high-polluting vehicles to pay a daily charge to enter designated areas. The revenue went straight back into public transit. By 2024, roadside nitrogen dioxide concentrations were an estimated 27% lower across the whole city than they would have been without the scheme, and 54% lower in central London. For the most deprived communities living near the busiest roads, researchers found an estimated 80% reduction in people exposed to illegal pollution levels. A University of Bath study put the public health savings at over £963 million, with measurable drops in sick leave and improvements in residents' reported wellbeing. The benefits, the researchers concluded, far exceeded the costs of implementation.
What San Jose Should Do Next
The point is not that San Jose should copy London's exact model. The point is that voluntary programs do not move the needle, and the region needs enforceable standards tied to consequences. That starts with replacing Spare the Air's advisory approach with binding vehicle emission requirements in the highest-traffic corridors, particularly those cutting through East San Jose. It also means attaching industrial permits to hard emissions caps rather than fines that polluters can absorb as a line item. San Jose is the capital of Silicon Valley, a region that has fundamentally transformed how the world communicates, works, and innovates. Few cities carry the same weight, and with it comes a responsibility that extends well beyond its own borders. A serious, enforceable clean air framework grounded in equity and backed by consequences, would set a precedent that reaches far beyond Santa Clara County. American cities struggling under the same cycle of voluntary programs and broken benchmarks would have a proven model to adopt. Most importantly, it would represent a turning point for the generation currently inheriting this problem and a demonstration that cities are capable of choosing their future.
References
Demerritt, E. (2023, April 26). Santa Clara County air quality earns failing grade. San José Spotlight. https://sanjosespotlight.com/santa-clara-county-poor-air-quality-earns-failing-grade/
IQAir. (2024). San Jose air quality index (AQI) and USA air pollution. https://www.iqair.com/us/usa/california/san-jose
London City Hall. (2025, March). London-wide Ultra Low Emission Zone one year report. Greater London Authority. https://www.london.gov.uk/programmes-strategies/environment-and-climate-change/environment-and-climate-change-publications/london-wide-ultra-low-emission-zone-one-year-report
Beshir, H., & Fichera, E. (2025, April). London's low emission zones save lives and money. University of Bath Institute for Policy Research. https://www.bath.ac.uk/announcements/londons-low-emission-zones-save-lives-and-money-new-study-finds/
American Lung Association. (2024). State of the Air 2024: Santa Clara County. https://www.lung.org/research/sota/city-rankings/states/california/santa-clara