BROOKLYN, Md. (WJZ)– Tracking bad air by zip codes has produced some worrisome numbers in Maryland.

Alex DeMetrick reports some of the most polluted air in the nation is in the communities of Curtis Bay and Brooklyn.

READ MORE: Maryland Weather: Clouds & More Clouds, Plus Friday's An Alert Day

The zip code that covers Curtis Bay and Brooklyn has two distinct features. Lots of big trucks rumbling through…

“Yeah, everyday. Constantly going up and down this road through Curtis Bay,” David Shaffer, a Brooklyn resident, said.

…and some very bad air pollution.

“In 2007 and 2008, it was the first in the country in terms of toxic air emissions released in that zip code,” Leah Kelly of the Environmental Integrity Project said.

The Environmental Integrity Project analyzed air monitoring and found improvements when a nearby coal-fired power plant spent millions to reduce pollution.

“It’s No. 74 in the country now, but it’s still No. 1 in the state,” Kelly said.

READ MORE: Jury Acquits Man Of Murder Of Baltimore Anti-Violence Advocate Dante Barksdale

“It’s terrible. Sometimes there’s a certain odor come through here,” Michael Askins, a Brooklyn resident, said.

And the steady exhaust from trucks and cars is believed to be a major cause. Ground level ozone, or smog and fine particles, are heaviest in South Baltimore.

“The particles are so small they can lodge more deeply into the lungs and carry more pollutants into the respiratory system,” Kelly said.

But if heavy truck traffic is a problem, there is also an understanding in this community of the need for trucks.

“They got to work. They got to make a dollar,” one resident said.

“That’s part of their job. Tanker lines are right down the street, so they have to go through,” Lori Claggett of Brooklyn said.

But the group doing the study thinks it can be eased if the city re-directs routes, keeping big rigs away from residential areas.

MORE NEWS: Baltimore County Firefighters Rescue Person Trapped In Mud Near NCR Trail

Besides new truck routes, the Environmental Integrity Project plans to push state and federal authorities for air monitoring in the zip code. Previous monitors have been removed.