Since diesel fumes are so smelly and bad for the environment and children, why are schoolbuses still diesel?

Newer buses run on compressed natural gas.

One, even non-diesel buses are smelly and bad for the environment. Even a 100% electric bus would be bad for the environment, as right now most of the world’s electricity is produced via polluting means, so increasing the amount of electricity required by each city would increase the number of generating stations thus increasing pollution levels overall. Diesel buses are still better than each parent driving their child in by themselves, not only for the environment but simply due to the number of car accidents that happen each day.

Two, who exactly is going to pay for the new fleet of buses? No one wants to, thus it’s not done. As well, “If it ain’t broke, don’t fix it” is generally the mindset many companies take. But this can be combined with making buses more eco-friendly. For instance, in my city, whenever a public bus finally dies, they replace it with an eco-friendly bus which I believe contains hybrid components.

Three, pretty much everything is more toxic to children due to their small body size. I would be interested in seeing some statistics regarding diesel versus gasoline fumes in relation to a child’s health, as well as overall child mortality statistics, as right now I cannot agree that diesel fumes pose a serious risk for children in relation to other risky activities they take part in. If your main concern here is the safety of children, there are many other ways this can be accomplished.

All diesel engines (manufactured 2007 and later) also have particulate filters attached which meet with EPA regulations.

In addition, I agree with dynamicduo in the third point. People assume that just because you can sometimes see diesel fumes (in the form of a black puff—which, on personal vehicles is due to either 1. poor maintenance or 2. “tuning” the vehicle to do so because the driver thinks it is cool) or can smell it easier than gasoline fumes (perhaps because we are all so used to smelling gasoline fumes, so we do not necessarily notice them as much anymore—Living in farm country, I am around diesels more than the average person, and I do not notice their smell anymore than a gasoline vehicle) that diesel is worse for humans and the environment than gasoline. Actually, the process of making diesel is BETTER for the environment than that for making gasoline, as it requires a much smaller amount of oil and is a quicker process. Also, with a few VERY simple conversions, a diesel engine can easily run on bio-diesel. It takes a lot more for a car to be converted.

Buses are expensive, and have a long lifespan. Where is the money going to come from to replace a school district’s fleet of diesel-burning buses with hybrid or natural gas-powered buses? Where is the money going to come from to maintain those buses?

Diesel engines are generally more powerful than gas ones – pretty much all trucks are diesel. It’s not clear that it’s much dirtier now that we have post-combustion traps and low (and ultra-low) sulfur diesel fuel. The fuel burns dirtier, but you get more miles per gallon, and the net change differs across the board of pollutants. Also, there’s biodiesel, as @dim mentioned, which is somewhat cleaner and is much better climate-wise (esp if it’s made from waste oil).

Compressed natural gas (CNG) is surely better, but it’s a pricey technology, and these are old fleets. Also, as to @dynamic’s point that we don’t get something for nothing and that electricity is also polluting – very true. However, it’s not the case that switching to electric would increase pollution overall. Most electirc grids are, on a per-mile-traveled basis, cleaner than gas or diesel. The dirtiest few grids in this country or elsewhere that run entirely on coal are about the same as running those cars on petrol. However, as an environmental policy guy, I’d rather see the pollution all in one place (so-called point source) where we can go after it easily. Utility companies are regulated by the state and are easier to coerce than millions of car owners, each with their own circumstance.