Chicago's South and West Sides among top hotspots for air pollution

Chicago's South and West sides and Northwest Indiana deal with some of the country's heaviest air pollution, known as PM2.5.

• The two areas ranked third- and fourth-worst in the nation, according to a new Guardian analysis of research from a team at the University of Washington and Virginia Tech.

Why it matters: This type of pollution, made of fine particles, can travel deep into the lungs and blood, increasing the risk of death from respiratory disease, heart attacks and strokes, studies show.

Context: The new research comes on the heels of an EPA data analysis by the Tribune showing that Cook County's air pollution contributes to more smog violations in neighboring states than any other county in the nation.

• It builds on several years of research warning about high levels of ozone and particle pollution from industrial sources on the South and West sides, especially in low-income communities of color.

What they're saying: Brian Urbaszewski of the Chicago-based Respiratory Health Association tells Axios the findings aren't surprising.

• "There are huge numbers of soot-blowing diesel trucks going to and from the industrial and freight sites concentrated largely in lower-income minority neighborhoods."

Between the lines: Urbaszewski says the study highlights the need for state legislation requiring "a phase-in for sales of zero-emission electric trucks like seven other states have already done."

• "At a time when Black children are going to the emergency room for asthma attacks at five times the rate we see for white children, there ought to be alarm bells going off that action to clean up trucks is needed," he said.

Zoom out: The only areas of the nation that scored worse for PM2.5 were parts of Los Angeles and Bakersfield, California.

Go deeper: Read the full list and track air quality across the country