CLIMATEWIRE | EPA’s proposal to limit toxic pollution from heavy-duty trucks is stronger than anything that has come before it. But state and local air quality agencies say it’s not aggressive enough to meet the federal regulator’s own clean air standards.

The National Association of Clean Air Agencies — which represents 115 local air pollution control agencies across 41 states, four territories and the District of Columbia — estimates that more than a third of the U.S. population lives in an area that does not meet federal air quality standards. One of the reasons: truck traffic.

Now, as EPA moves to limit heavy-duty truck emissions, it is also creating stricter standards for particle air pollution. But the NACAA says the draft truck rule is too weak to help states meet current air quality standards, let alone the new ones.

“EPA is ratcheting up the number of areas that aren’t meeting health-based air quality standards at the same time they’re proposing a rule that isn’t protective enough for the most important source of that exact pollution,” said Miles Keogh, NACAA executive director.

Heavy-duty trucks are the largest mobile source of nitrogen oxides, which can react in the atmosphere to form toxic pollutants like ozone and particulate matter. While states can reduce emissions from stationary sources like power plants and factories, they largely lack the authority to regulate emissions from cars and trucks, which fall under the purview of the federal government.

That means without a federal rule to sufficiently curb NOx emissions from 18-wheelers, delivery vans and dump trucks, states are running out of ways to come into compliance with air quality standards, analysts say.

“In the 1970s there were more opportunities for emissions reductions because we had not yet started to reduce emissions,” said Julian Marshall, a civil and environmental engineering professor at the University of Washington. “But the easy stuff has already been addressed, so the number of [pollution] sources they can control is getting smaller and smaller.”

EPA last updated its federal standards for NOx emissions from heavy-duty trucks 20 years ago, during which time the public’s health suffered. Exposure to toxic air pollution is linked to a host of ailments, including heightened risk of early death and poor lung development in children. Transportation is also the single-largest source of greenhouse gas emissions in the country.

Communities of color and low-income neighborhoods have borne the brunt of that pollution, as they are disproportionately located near highways, freight corridors, rail yards and warehouses, according to EPA.

President Joe Biden has pledged to address these disparities, in part by updating emission standards for heavy-duty trucks. But EPA’s proposed rule, which was released in March, came as a disappointment to environmental and public health experts who had hoped for a stronger regulation (Climatewire, April 14).

Along with advocates living and working in these heavily polluted areas, the experts urged EPA to issue a truck rule in line with California’s recently enacted Heavy-Duty Omnibus program, which requires a 90 percent reduction in NOx emissions by 2027 compared to 2010 standards.

EPA’s proposal outlined two approaches. The first option mirrors California’s rule, but is not as strong. The second, less stringent option is more in line with what truck- and engine-makers have pushed for (Greenwire, March 8).

"This administration has put addressing racial inequities as a priority," said Ray Minjares, who heads the International Council on Clean Transportation’s heavy-duty vehicles program. "And we’re just not seeing that in this rule."

Community members have continued to meet with EPA staffers at least once a month, but say they feel overlooked (Climatewire, May 16).

Meanwhile, EPA is slated to propose stronger particulate matter limits this summer, after an advisory panel delivered a pivotal review recommending the agency tighten both annual and daily exposure limits (Greenwire, March 22). While EPA has no plans to tighten NOx limits in their own right, those criteria pollutants are one of the major contributors to particulate matter as well as ozone.

“EPA’s rule as proposed really leaves people up the river as far as getting those NOx reductions,” Keogh said. “Our agencies can’t squeeze it out of the sources we’ve got, and we need the feds to set a sufficiently protective standard for these trucks.”

In Phoenix, Ariz., for example, smoke stacks are few and far between, Keogh said.

“That haze over the mountains is coming from mobile sources,” he said. “It’s coming from cars and trucks.”

Another example can be found in Wisconsin, where there are several areas that do not meet federal air quality standards. The largest contributor of NOx emissions in Wisconsin comes from vehicles traveling in and through the state. And nearly half of those emissions come from heavy-duty trucks, according to the 2017 National Emissions Inventory.

EPA spokesperson Taylor Gillespie pointed out that the agency’s truck rule is a proposal, not a final regulation.

“We had an extended comment period for people to weigh in and provide feedback which just closed last week,” she said in an email. “We are currently reviewing those comments and look forward to addressing concerns in the coming months.”

Gillespie also noted the rule is the first phase of the agency’s broader plan to address pollution from trucks.

Cleaner air, but ‘disparities remain’

While researchers and those affected have long understood the health consequences of living and working in the shadow of the heavy-duty trucking industry, new research has increasingly laid bare the systemic nature of the disparities.

A study published this year in the journal Environmental Science & Technology Letters found a correlation between redlining — a discriminatory mortgage appraisal practice from the 1930s — and air pollution levels in Black neighborhoods.

“This is what many communities have been saying for decades, that the risks from air pollution are not felt equally across members of our society,” said Marshall, who co-authored the study. “And ethically, that’s almost its own separate reason to care about air pollution. There’s this fairness aspect to it.”

Marshall said one reason for the disparity is because in the 1960s the federal government routed freeways directly, and often intentionally, through Black and low-income neighborhoods — a historical wrong the Biden administration has said it wants to help remedy (Climatewire, Dec. 8, 2021).

Another study published last year in the journal Proceedings of the National Academy of Sciences found that early in the Covid-19 pandemic, overall levels of toxic pollution decreased the most in Black, Latino and low-income neighborhoods as people stopped driving to work.

But those communities still experienced higher levels of pollution compared to the levels majority white and affluent areas faced even prior to the pandemic. That’s in part because while passenger vehicle traffic decreased during the pandemic, heavy-duty trucking did not.

Similarly, in a draft policy assessment for its particulate matter rulemaking, EPA staff found that Black communities would experience proportionally greater benefits from stricter particulate matter air quality standards, but they would still face higher rates of premature mortality risks from toxic pollution compared to other groups.

“Over time, the air has gotten cleaner, yet the disparities remain,” Marshall said. “So we really need to look for opportunities, like with diesel emissions, to find the sources that lead to some groups being more exposed than others and address those sources.”

EPA is slated to release its final truck emissions rule before the end of the year.

Reprinted from E&E News with permission from POLITICO, LLC. Copyright 2022. E&E News provides essential news for energy and environment professionals.