It’s no secret that California’s schools are underfunded. The state spends more on prisons that it does on educational funding. In 2012, Governor Jerry Brown cut $248 million from schools to help remove $1 billion in state spending. One the hardest hit areas in the budget is transportation to and from school.

As it is, thousands of children ride to school on old yellow buses that likely haven’t been updated for decades. There’s certainly no money to replace these dinosaurs of transportation, iconic though they may be, and now it seems that the buses are polluting beyond state standards.

While most Californians are required to submit to regular smog checks to register their vehicle, the state doesn’t require buses to be taken off the road after a certain amount of years as in other states. Many of the school buses are the oldest in the nation, meaning children are regularly exposed to pollutants.

Buses made before 1990 were created to adhere to a different set of standards than we have become used to today. Now, it’s not uncommon to see city buses that advertise themselves as low emissions. Others run on natural gas, as opposed to diesel. Newer buses emit six times less pollutants than the pre-1990 counterparts.

This problem hasn’t gone unnoticed by legislators. The state is working on passing regulations that would require all school buses to undergo a retrofitting of filters for pollutants or be taken off the road by 2018. The retrofits cost $17,900, roughly, and a new bus costs around $150,000 for traditional fuels and $230,000 for electric powered.

Originally, the state cut all funding to transit for schools, but there is still some funding available. There was traditionally a budget for bus maintenance and replacement through the ‘60s and ‘70s that was gutted as the financial strain grew for schools in California.

There’s clearly no money in the budgets for a new bus, but the retrofits are not a sustainable solution. They’re more of a stop-gap measure to cut pollutants. Eventually, the buses will break down and there may not be enough money to replace them. Now schools have to wonder what’s worse — exposing children to the pollutants or not having a bus at all?