Scientists at the University of California, Berkeley found exposure to high levels of pollution lead to health problems in both infants and adults. The study had only limited evidence to demonstrate there was an increase in adult mortality, though some evidence pointed to higher mortality in the elderly .

Conducted by Michael L. Anderson, a member of the department of Agricultural and Resource Economics, the study entitled "As The Wind Blows" looked at the health of people living or spending large amounts of time near major highways in Los Angeles by using geo-coded data to see their location. Data was gathered over the course of several years and was combined with census data and wind-pattern tracking.

Both infants and adults were shown to have increased health problems if they lived downwind from a highway, the study reported.

Though there was no overwhelming evidence demonstrating a causal link between exposure to pollution and higher mortality, the data did point to a possible link between the two in the elderly. Doubling the amount of time spent downwind of a highway bumped mortality from 3.6 percent to 6.8 percent in people more than 75 years of age.

Pollution has long been a problem in Los Angeles, a city known for its smog. As the city is sprawling and public transportation more limited than in comparable cities, most people drive cars, and the carbon emissions cause a visible pollution problem: smog.

Los Angeles frequently tops lists of the most polluted cities in the world, and recent figures reported the city has unsafe ozone levels 122 days out of the year. A recent drought has made air quality even worse, the Los Angeles Times reported in April.

"Air pollution is not just a nuisance or the haze we see on the horizon; it's literally putting our health in danger," Bonnie Holmes-Gen of the American Lung Association in California told the Los Angeles Times.