LOS ANGELES (CBSLA) — Los Angeles has seen 57 straight days and counting of unhealthy air quality and health experts are concerned.

Late summer is a bad time of year for air pollution due to hot temperatures, slack winds and high emissions. The long hot summer days cook the chemicals in the air that form smog.

“You can see that scattering from the particles and the gasses in the air so you see that characteristic brown smear [on the horizon],” says Professor Ed Avol, Director of Environmental Health at the USC Keck School of Medicine. “It’s getting in your lungs and what you see is what you’re breathing.”

Avol says the old, the very young and people with pre-existing conditions are particularly vulnerable to the toxic effects of smog. Other at-risk groups include pregnant women, because the toxins can get into the mother’s blood stream, outdoor workers, who can be exposed for long periods of time, and athletes, because they take deep breaths and draw the pollutants deep into their lungs.

Angelenos can limit the damage by avoiding the hottest parts of the day and when the streets are full of vehicles.

“Walking through a neighborhood rather than along a busy thoroughfare actually reduces your exposure,” Avol says. “I think we ought to be thoughtful about where or how we might get exposed , or have the opportunity for exposure.”

L.A.’s infamous smog, a witch’s brew of soot, dust, gases and ozone, has generally diminished over the past two decades, but worsened slightly in the past few years.

“While we’ve seen overall improvement in air quality in California, not all communities receive the same benefits of clean air. The gains are uneven and we still see low-income communities and communities of color face the highest burden of pollution,” said USC Keck School of Medicine Assistant Professor Jill Johnston.

Johnson, an expert in community health, notes that freeways, industrial sites and ports concentrate air toxins in poor communities.

The city’s children may be the biggest victims of LA’s long stretch of poor air quality.

“Kids are very vulnerable to air pollution because damage done when they’re developing can’t be undone. The effects are lifelong and they include loss of lung function, asthma, obesity, diabetes and neurological disorders,” Frank Gilliland, an expert in children’s respiratory health at USC says.

Gillard adds that new evidence shows long-term health damage and disease systemic in the body, even at lower levels of pollution and that kids in smoggy places like L.A. suffer about 10% less lung function.