A week after climate change-driven wildfires worsened air pollution and exacerbated environmental justice concerns in the region, advocates and health experts have urged Maryland’s environmental regulator to hasten efforts to reduce transportation emissions and electrify the state’s on-road vehicles by adopting the Advanced Clean Cars and Clean Trucks Rules. 

The call to act came with the Wednesday release of two new studies by the Sierra Club Maryland Chapter and the Union of Concerned Scientists. 

Both studies simulated effects of vehicular emissions on Maryland residents and the environment, and the cumulative impact on minority communities, and argued that moving to electrify on-road transportation quicker would benefit the state, the environment and Marylanders.

As the studies were released, the Maryland Department of the Environment (MDE) held a public hearing on adopting the Advanced Clean Cars program, or ACC II, which was approved by the California Air Resources Board in August 2022 and is being considered by other states. ACC II will require manufacturers of passenger vehicles and light trucks to increase EVs’ share of annual new vehicle sales in the state. 

The Advanced Clean Trucks (ACT) regulation, established under the Clean Trucks Act of 2023 signed by Gov. Wes Moore in April, will require the same thing from manufacturers of medium and heavy-duty vehicles. 

The UCS’s draft research simulated three scenarios with varying degrees of vehicle electrification and estimated their impact on grid decarbonization efforts and the resulting climate, environmental and health benefits.  

The Sierra Club-commissioned modeling confirmed the massive contribution of emissions from on-road vehicles to ozone pollution in Maryland and estimated that medium- and heavy-duty vehicle pollution contributed the majority of transportation-generated ozone. 

“Modeling reveals that adoption of the Clean Trucks Rule alone would cumulatively reduce tailpipe NOx [nitrogen oxide] emissions from medium- and heavy-duty vehicles by 63,000 metric tons through 2050,” the nonprofit stated in its public comments on the adoption of the clean car rule.

“Reducing ozone pollution and nitrogen oxide (NOx) emissions, a precursor to ozone pollution, is essential to reducing the unequal public health harms unjustly borne by low-income populations and people of color in Maryland,” the Sierra Club said.   

By implementing the ACT rule, the state would also avoid 46.45 million metric tons of greenhouse gas emissions by 2050, the nonprofit added.

In view of their findings, the Sierra Club and the Union of Concerned Scientists urged the MDE  to publish the ACC II and ACT Rules in 2023 and swiftly implement the regulations in Model Year 2027. The agency is currently moving to implement both under the Moore administration and the Maryland General Assembly. 

“Heavy duty trucks are the largest producer of nitrogen oxides (NOx) in Maryland, which affect local air quality and contribute to ground-level ozone—one of the most stubborn and dangerous air pollutants we deal with here in Maryland,” said Chris Hoagland, director of air and radiation at the Maryland Department of the Environment. “So, it’s an extraordinarily important transition.”

The Advanced Clean Cars II regulation will require manufacturers of passenger vehicles and light trucks to increase EVs’ share of annual new vehicle sales in the state. The Advanced Clean Trucks regulation will require the same thing of manufacturers of medium and heavy-duty vehicles, Hoadland explained.

The implementation of the ACC II program will begin with the 2027 model year and culminate in requiring electric vehicles to make up 100 percent of sales requirement by model year 2035. It would also require increasingly stringent pollutant standards for vehicles with internal combustion engines during the period in which they continue to be sold.

In April, Moore signed the Clean Trucks Act of 2023, which applies to vehicles from the model year 2027 onward. 

As part of the implementation of the new clean trucks rules, the MDE is required to adopt regulations by December that establish sales targets for manufacturers through 2035. Environmentalists and advocates hailed the clean trucks law as a significant step toward eliminating toxic air pollution. 

The transportation sector is one of the chief contributors to greenhouse gas emissions in the United States, according to the Environmental Protection Agency, accounting for 27 percent of the total in 2020. Aside from warming the planet and causing heat waves, drought, storm surges and floods, the health impact of greenhouse gas emmisions have long been a concern for federal and state agencies. 

A 2022 study found that in 2019 alone, 1.8 million excess deaths around the globe could be attributed to urban air pollution. The study showed that 86 percent of adults and children living in cities were exposed to a level of fine particulate matter that exceeded World Health Organization guidelines.

Of particular concern is exhaust from diesel trucks, which is a potent source of fine particulate matter pollution, known as PM2.5. The analysis by the Union of Concerned Scientists found that the city of Baltimore had the worst pollution levels in Maryland, with an exposure rate that was 37 percent higher than the state average, followed by Prince George’s County, with a rate that was 23 percent higher. 

Historically, Maryland’s high ozone levels have exacerbated race- and income-based health disparities and have a major impact on Maryland’s environmental justice communities. Adopting clean car standards was “an important first step in providing Baltimore’s environmental justice communities with the clean air they need and deserve,” the Sierra Club said in its comments. 

In 2019, Maryland’s Health Service Cost Review Commission found that Black or African American children made up 88 percent of pediatric asthma-related hospitalizations and 87 percent of emergency department visits in Baltimore City.

“We’re now experiencing hotter and hotter days. And when we have this increased heat, particularly in urban heat islands, the nitrous oxides that come from tailpipe emissions interact to form ozone, which is harmful more readily,” said Dr. Christine Berg, an oncologist and cancer risk expert. 

She said that the increasing temperatures from global warming escalate the development of the ground-level ozone to higher levels than would occur without the effects of climate change. 

“And the recent poor air quality from the wildfires, in addition to the particulates we already have from the transportation sector, from our industrial and energy-producing sector, is having an additive effect,” Berg said. 

“Increasing temperatures and wildfire smoke, dust storms, and other climate induced changes will worsen effects from other sources of pollution. Research into combined effects of more than one source of pollutants is complex and slowly starting,” she added.

A 2021 report by Maryland PIRG, a public interest advocacy group, delved into how air pollution and climate change have entered into a feedback loop with one another. 

“Higher temperatures have already resulted in increased ozone, despite lower emissions of the chemicals that create ozone,” the report said. 

Higher average temperatures also make extreme heat events more likely, and drive bigger and longer-lasting forest fires that spread PM2.5 and the precursors to surface-level ozone pollution. Many areas susceptible to drought, such as the southwestern United States, are likely to see even less rain in the future as the climate changes, exacerbating the dry, dusty conditions that spread particulate matter.

Gov. Moore announced in March the state’s adoption of the Advanced Clean Cars II rule, calling it a major step to improve air quality and combat the effects of climate change.

The MDE then moved to present the proposed rule to the state’s Air Quality Control Advisory Council, which recommended that the agency take all necessary steps for enacting the new standards, including Wednesday’s public hearing, to allow for the regulations to take effect in September.