South Bronx Sees Air Quality Dip as Congestion Pricing Shifts Traffic—Asthma Relief Remains in Transit

As Manhattan’s congestion pricing clears the air downtown, a new study reveals that the South Bronx is choking on the unintended consequences—a cautionary tale for urban planners everywhere.

On winter mornings along Bruckner Expressway, a haze clings to the rowhouses and schoolyards of the South Bronx—a neighbourhood already shadowed by some of the highest asthma rates in America. Now, science has confirmed what locals have long sniffed: after New York City’s congestion pricing began last year, the borough’s notorious air pollution has only worsened. A new Columbia University study, published on May 8th, reports “significant increases” in harmful particulate matter near expressways, raising questions about who really pays when traffic tolls aim to save a city’s lungs.

The experiment began in early 2025, when the Metropolitan Transportation Authority (MTA) launched a $15 daytime fee on motorists entering Manhattan below 60th Street. This congestion pricing scheme, long hailed by transit advocates and environmentalists, was designed to cut traffic, curb emissions, and fill the MTA’s ailing coffers. For many, the trade-off seemed straightforward: less pollution downtown, funds for subways and buses, and a gentler carbon footprint.

Yet, as the Columbia researchers explain, fine-print matters. Their analysis of two years of data from 19 Bronx air quality sensors reveals a patchwork outcome. Four sensors near expressways detected statistically significant upticks in PM2.5, the most insidious type of traffic-borne pollutant. Two others showed decreases, while the remainder found little change. The source, as predicted in the MTA’s own 2021 environmental review, appears to be diesel trucks and cars rerouting through the Bronx to duck the midtown tolls.

If this sounds parochial—just another borough shouldering Manhattan’s burdens—the numbers tell a grimmer story. The South Bronx is disproportionately low-income and predominantly nonwhite; decades of redlining and highway-building have left it marbled with truck routes and public health woes. Local hospitals already treat asthma and respiratory illnesses at double the citywide rate. The MTA, aware of the risk, promised a modest $70m in mitigation: asthma programs, some electric delivery trucks at Hunts Point Market, and a grab bag of air-quality initiatives. Most are still in rollout, and none, it seems, have caught up with the scale of the problem.

What can be measured in the Bronx contrasts baldly with the wider story the MTA would prefer to tell. A separate Cornell University study last year noted an overall improvement in regional air quality after congestion pricing’s debut. Yet citywide averages obscure microclimates: for residents sandwiched between the Cross Bronx Expressway and Major Deegan, traffic and tailpipe haze are daily facts, not actuarial abstractions. “Mitigation can’t be adding a Band-Aid onto a wound that’s already infected,” said David Rosales of South Bronx Unite, the local nonprofit that partnered with Columbia for the research. For these communities, “right now… people can’t breathe.”

Though the MTA’s planners anticipated some displacement of pollution, the magnitude and speed have come as a rude surprise. The data present a classic case of environmental externalities: benefits are socialised across Manhattanites, while costs are quietly localised elsewhere. The city risks recapitulating its own history, where each major civic improvement—be it parks, expressways or subway expansions—has often had a winner and a loser, with the Bronx too often cast as the latter.

Local politics have responded in kind. Bronx leaders, already bristling from news that subway upgrades have disproportionately favoured Manhattan, now find themselves asking whether upstate lawmakers and midtown commuters grasp what “shared sacrifice” means in practice. The borough’s representatives argue for more targeted relief: electrifying truck fleets, retrofitting highways with pollution barriers, and routing freight away from residential streets. Such measures carry sticker prices that dwarf the MTA’s current mitigation budget.

Unintended consequences abound in the age of the urban toll

The South Bronx’s plight is not unique, nor is New York the first city to discover the perils of shifting congestion around rather than banishing it outright. London’s congestion charge, introduced in 2003, nudged some traffic into outer boroughs, sparking similar complaints. Stockholm’s scheme, often held up as a model, has tried—largely successfully—to balance air improvements across districts, sometimes by reinvesting toll revenue disproportionately in affected areas. That should be a lesson for Gotham: policies that work citywide may nonetheless manufacture neighbourhood-level losers without granular data and real political will.

Globally, urban tolling is having a moment; cities from Milan to Singapore tout cleaner air and easier commutes. But rushed or poorly-targeted schemes risk producing exactly the kind of injustices that erode public trust in green policy. Environmental wins counted in citywide averages can mask a distribution of costs that fails the basic test of fairness. Or, to spin an old New York phrase, “deals” struck for downtown may wind up leaving uptown wondering when its cut will arrive.

We reckon congestion pricing remains a vital tool in the big-city kit. Manhattan’s streets had reached an impasse, both figuratively and literally; the toll has delivered measurable benefits in transit funding and air quality where it counts. But any policy predicated on “market signals” must internalise all the costs, not simply transpose them. When the buck stops in the poorest borough, the ledger—not to mention the air—remains out of balance.

The challenge, then, is not to torpedo congestion pricing, but to tweak and target its second-order effects, transparently and fast. The MTA’s $70m for mitigation is tepid compared to the scale of the shift and the health costs already accruing. Smarter logistics, targeted infrastructure, and perhaps a larger cut of toll revenue ringfenced directly for affected districts could redress the local ledger.

Social progress in cities is seldom tidy and rarely painless. The true test of an urban policy is not only what it delivers at the aggregate, but how nimbly it acknowledges and repairs its blind spots. Manhattan can breathe easier thanks to congestion pricing; we trust New York’s planners will not leave their neighbours gasping. ■