By Ashley Verhines
Many recent studies have shown that air pollution levels and income levels are linked. Poorer communities suffer from bad air more than wealthy communities. A recent study by UCLA researchers revealed some complications in this correlation, but found that air pollution is still about environmental justice.
The researchers drove a zero-emissions vehicle through four residential Los Angeles neighborhoods to collect data on real-time concentrations of toxic ultrafine particles. Mar Vista's North Westdale, a middle-class neighborhood downwind of the Santa Monica Airport, scored worst. Surprisingly, the freeway-surrounded Boyle Heights neighborhood scored slightly better for these pollutants, followed closely by downtown Los Angeles. Less surprisingly, the affluent West Los Angeles neighborhood scored significantly better than the other three.
Freshly emitted ultrafine air pollutants are known to cause asthma, heart attacks, stroke, diabetes, low birth weight and other health complications. Focusing on these types of pollutants instead of smog and ozone--which have been the subject of significant prior research--was critical to the study, which was published in the journal Atmospheric Environment. Suzanne Paulson, a professor in UCLA's Atmospheric and Oceanic Sciences Department and the Institute of the Environment and Sustainability directed the research with Arthur Winer, a professor in UCLA's Fielding School of Public Health, and Wonsik Choi, a postgraduate researcher who led the fieldwork and drove the vehicle that collected the air samples.
The researchers found that while there were no significant differences in more traditional air pollutants like larger "PM2.5" particles between neighborhoods, readings of the tiniest airborne particles, the concentration of ultrafine particles (less than 0.1 microns in diameter) varied widely between neighborhoods on summer afternoons.
"The North Westdale neighborhood is heavily impacted by aircraft activities at Santa Monica Airport," said Suzanne Paulson. "It has exceptionally high levels of ultrafine particles when aircraft are active, possibly among the highest concentrations of any neighborhood in the Los Angeles area."
Boyle Heights, a less well-off neighborhood near downtown LA, is similarly affected by roadway pollution. "It is nearly surrounded by freeways and crisscrossed by major arterial roads," Paulson said. "These streets carry a large number of high-emitting older vehicles, and its neighborhoods are characterized by short blocks with abundant stop signs, causing frequent emission spikes from accelerating of vehicles."
But vehicle emissions are not the only source of ultrafine particles found in these neighborhoods. "In Boyle Heights, and to a lesser degree downtown, there are additional ultrafine particles that are not freshly released from vehicles but instead form in sunlight-driven smog processes and are ultimately the result of pollution blown in from upwind areas to the west," Paulson said.
Although their findings indicate that all kinds of neighborhoods may face dangerous levels of air pollution, the researchers found that air quality is still an environmental justice issue, with poorer neighborhoods more likely to face greater pollution. "Despite substantial improvements in regional air quality, cleaner air remains a highly desirable amenity in Southern California," said Arthur Winer. West Los Angeles, the most affluent of the four neighborhoods, still experienced the lowest concentrations of ultrafine particulate matter. Furthermore, it experienced a significant decrease in ultrafine particles in the last few years, which also can be explained in terms of its wealth.
"The decrease in ultrafine particles between 2008 and 2011 in the West Los Angeles area was dramatic," Wonsik Choi said. "Affluent West Los Angeles experiences rapid turnover of the vehicle fleet, resulting in a higher proportion of newer vehicles with cleaner engines and better fuel efficiency."
Higher property prices in neighborhoods with lower concentrations of noxious particulate matter is one way that residents implicitly signal that they value the quality of their air. Consequently, the lack of purchasing power for the poor to live in neighborhoods with necessarily clean air continues to be a concern of environmental justice.
Photograph of Santa Monica Airport courtesy of Dawn Loh