CHICAGO -- Kevin Brown's most feared opponent on the sandlot or basketball court while he was growing up wasn't another child. It was the polluted air he breathed.
''I would look outside and I would see him just leaning on a tree or leaning over a pole, gasping, gasping, trying to get some breath so he could go back to playing," recalled his mother, Lana Brown.
Kevin Brown had asthma. His mother was convinced that the factory air covering their neighborhood triggered the attacks that sent them rushing to the emergency room week after week.
''I can't breathe! I have no air, I'm going to die!"
The air in the neighborhood where Kevin Brown played is among the least healthy in the country, according to a little-known government research project that assigns risk scores for industrial air pollution in every square kilometer of the United States.
An Associated Press analysis of that data shows that black Americans like the Browns are 79 percent likelier than whites to live in neighborhoods where industrial pollution is suspected of posing the greatest health danger.
Residents in neighborhoods with the highest pollution scores also tend to be poorer, less educated, and more often unemployed than those elsewhere in the country, AP found.
''Poor communities, frequently communities of color but not exclusively, suffer disproportionately," said Carol Browner, who headed the Environmental Protection Agency during the Clinton administration when the scoring system was developed. ''If you look at where our industrialized facilities tend to be located, they're not in the upper-middle-class neighborhoods."
With help from government scientists, AP mapped the risk scores for every neighborhood counted by the Census Bureau in 2000.
The scores were then used to compare risks between neighborhoods, and to study the racial and economic status of those who breathe America's most unhealthy air.