Diesel bus pollution costs a city up to 207,200 dollars a bus in health harm

What diesel bus pollution costs a city in health

Diesel bus pollution costs a city real money in health harm, and a 2024 study puts an exact number on it. Researchers at the Harvard T.H. Chan School of Public Health, publishing in the Proceedings of the National Academy of Sciences, found that replacing 1 old diesel school bus in a large city can be worth up to 207,200 dollars a year in avoided health harm, from asthma attacks to early deaths tied to the fine particles in diesel exhaust. The highest county figure they found runs even further, up to 822,000 dollars a bus in New York County, the single highest county the study measured. The lowest, Washington County in Maine, comes out slightly negative, around negative 800 dollars a bus, because so few people live near its routes that there is barely any health harm left to avoid. That spread, a real gain in a dense county and a small loss in a rural one, only shows up in the study own table listing every county, not its published summary.

The word bus in most of these numbers means school bus, not the transit bus a commuter rides to work. This is the richest and most current dataset among the 5 sources behind this article, and it counts diesel school buses nationally. A separate study grounds the same question in an actual public transit fleet, the Regional Transportation Commission buses serving Las Vegas and Clark County in Nevada. The 2 systems are counted separately below and never added together, since they use different fleets, different years and different methods.

An old diesel bus in a big city costs the most

An average diesel school bus in a large city carries a health benefit of 85,800 dollars a bus if replaced, but a bus still running from model year 2005, the oldest type still on the road, carries a health benefit of 207,200 dollars, more than double the average, because it burns dirtier and has been doing it longer. Nationally, the study ties the current diesel school bus fleet to 170 deaths and 280 childhood asthma cases a year from fine particulate matter, meaning the tiny airborne particles in diesel exhaust small enough to reach deep into the lungs, a toll researchers say would fall to 7 deaths and 12 asthma cases a year if every one of those roughly 480,000 buses ran electric instead. Kari Nadeau, the study senior author and chair of the Department of Environmental Health at the Harvard T.H. Chan School of Public Health, states the finding plainly.

In a dense urban setting where old diesel buses still comprise most school bus fleets, the savings incurred from electrifying these buses outweigh the costs of replacement.

Kari Nadeau, chair of the Department of Environmental Health at the Harvard T.H. Chan School of Public Health, senior author of the study. Source 4.

Public transit buses are a separate accounting

City transit buses are a different fleet, and their numbers come from a separate study. That study, run on the actual fleet records of the Regional Transportation Commission, the transit agency serving Las Vegas and Clark County in Nevada, found the county already captures a health benefit of at least 1,670,000 dollars a year from its cleaner bus mix, and could still reach up to 10,500,000 dollars a year if it finished cleaning up. The same study estimates that if every public transit agency in the country matched a fully clean fleet, the national health benefit could reach up to 4,110,000,000 dollars a year, avoiding as many as 258 premature deaths and more than 5,000 respiratory and cardiovascular illnesses a year. None of those transit figures should be combined with the school bus figures above, since the 2 studies count 2 different bus systems.