We are announcing the launch of a pilot study looking at how exposure to ultrafine particles from plane landings at LAX affects lung function and inflammation in adults with asthma. Our official launch date is May 18th, for a duration of two months.
Those interested in participating, please contact Dr. Rima Habre to obtain information. Click on the images below to read more…
How much has air quality changed in the Southern California region over the past 20 years? Are these changes related to specific policies to clean the air? Do air control policies or regulations actually work?
Center investigators have been working to understand the long-term effects of air pollution on our health. But as the air quality in our environment changes, how does that affect our health? To understand the health impacts of ongoing changes in the environment, it’s helpful to know what has changed in the air and why.
Recently, Center investigators reviewed the changes in air quality across southern California over the last 20 years. The findings of Ed Avol (USC Preventive Medicine), Frank Gilliland (USC Preventive Medicine) and Fred Lurmann (Sonoma Technology Inc, a long-time collaborator and contributor to much of our Center research) were the basis of a March 2015 publication in the Journal of the Air and Waste Management Association (JAWMA), entitled “Emissions reduction policies and recent trends in Southern California’s ambient air quality.”
As the JAWMA article details, there have been dramatic improvements in regional air quality across southern California over the past 20 years. Several key air pollutants, tracked by U.S. EPA, dramatically declined in outdoor concentrations between 1994 and 2011. Nitrogen dioxide (NO2), which is a by-product of engine combustion, decreased by 28% – 53% in communities from San Luis Obispo County to San Diego County. Inhalable particle matter (PM, microscopic pieces of dirt floating in the air, in specific size ranges, such as 2.5 microns, denoted as PM 2.5) decreased by 13% -54% across a similar range of communities and areas. Changes in ozone (O3) were less pronounced, improving by 12% – 27%, depending on the community.
Why did this happen, and what does it mean?
NO2 and PM2.5 are closely linked with “primary” emissions: that is, direct emissions from car and truck exhaust, power plants, industry, ocean-going ships, trains, and off-road construction equipment. As emissions from those sources have been reduced over the years, the air has become much cleaner. These improvements have come from the use of cleaner trucks at the Ports of Los Angeles and Long Beach and now through California, a mandated smog check program, requirements for cleaner fuels, requirements for cleaner engines on bus and truck fleets, and a push to get the oldest and dirtiest trucks off the road.
Ozone levels have been much more difficult to reduce, since ozone is not directly emitted by trucks or cars or power plants. Instead, it is a “secondary” pollutant, that is, it is formed in the daytime air by chemical reactions powered by sunlight and chemically enhanced by certain other pollutants in the air. Reducing these other pollutants slows down the production of ozone, but getting BIG reductions in this pollutant is much harder than for other pollutants.
What made these changes happen?
In southern California between the 1990s and today, regulators put hundreds of pollution policies and programs into place. The most effective collective programs included efforts to reduce on-road emissions. This makes sense, given that there are over 13 million cars operating in Los Angeles County! Remarkably, these air quality improvements occurred even though traffic increased 38%, population increased 30% , economic activity increased 66% and activity in and around the ports increased 160%.
Why did these policies work in Southern California?
There are a huge number of vehicles on the road, plus a busy port with thousands of trucks. This created a high baseline to start from, with emission reductions making a big difference collectively. In addition, by the 1990s stationary sources were already well controlled. Sources such as power plants are under local jurisdiction, and agencies such as SCAQMD enforced regulations. In addition, Southern California has no coal burning power plants, which create large amounts of emissions. These are factors that made the on-road vehicle regulations successful.
Selected clean air policies implemented between 1990 and today:
Regional Clean Air Incentives Markets Program (RECLAIM) (SC-AQMD), early 1990s.
Diesel particulate matter (DPM) named a toxic air contaminant in 1998. This led to the diesel risk reduction plan and new standards for all on-road, off-road, and stationary diesel-fueled engines and the sulfur content of diesel fuel, 2000 (CARB).
San Pedro Bay Ports Clean Air Action Plan (CAAP), 2006.
There are several important points to remember here. We still don’t have “clean air” on some days across Southern California, but there has been a lot of progress. These major policy actions by local, regional and state government agencies and the ports went beyond what was required from federal regulations. The improvement in air quality is a real success story, but we need to keep up the effort so that more days are “clean” and our air quality meets the levels that science and regulators agree are necessary to protect our health. To see what effect this improvement has had on our health, check out the related research (Gauderman, et. al 2015,Berhane, et. al 2016) done by our investigators during this same period of time.
The South Coast Air Quality Management District (SC-AQMD) has recently produced a fantastic YouTube video, “Do One Thing” The 9:45 minute video takes a look at the air quality in the LA basin, associated health effects, and what one person can do to make a difference. The video helps remind us of simple things we can do in our daily lives to make a difference in our environment and the air we breathe: things such as riding our bikes on short trips close to home, riding mass transit, and even walking to school with our kids one day a week. The video also highlights personal stories of how people’s health and that of loved ones has been affected by the pollution in the Southern California region. Watch and be inspired to make a difference and “Do One Thing” (or maybe more)! (Note: We are not biased even though this video features two of our researchers: Ed Avol and Rob McConnell).
For related information on the health effects of traffic related pollution, click through to see this infographic.
Our Center members and outreach program have been involved in discussions, meetings, and planning regarding the I-710 Corridor for much of the previous decade. This has included speaking at public hearings, participating in planning sessions, providing the latest scientific research findings to involved policymakers and commenting on potential alternatives developed by the LA County Metropolitan Transportation Authority (METRO), Caltrans, and the Gateway Cities Council of Governments, the regional organization providing a forum for the 21 cities adjacent to and/or directly impacted by the I-710 Freeway. Our primary concerns have centered on the health impacts of near-roadway air pollution. Expanding the number of lanes on the I-710 means that freeway pollution will be closer to homes, schools, and parks. Today’s article in the Los Angeles Times describes the current CalTrans plans which appear to be supported by Southern California Assn. of Governments. Also note, an alternative that has been offered by the Coalition for Environmental Health and Justice.
Many studies have measured the health effects of pollution by comparing locations with different air quality. The challenge lies in ruling out other factors that may account for health differences between communities.
By following more than 2,000 children in the same locations over two decades and adjusting for age, gender, ethnicity, height, respiratory illness and other variations, the study provides stronger evidence that improved air quality by itself brings health benefits – benefits which last a lifetime for children breathing cleaner air during their critical growing years.
“We saw pretty substantial improvements in lung function development in our most recent cohort of children,” said lead author W. James Gauderman, professor of preventive medicine at the Keck School of Medicine of USC, noting this was the first good news from the long-running study.
“It’s strange to be reporting positive numbers instead of negative numbers after 20 years.”
Widely-covered previous findings from the study showed an increase in stunted lung development for children in areas with heavy air pollution, as well as a higher risk of asthma for children living near busy roadways.
Combined exposure to two harmful pollutants, nitrogen dioxide (NO2) and particulate matter of diameter under 2.5 microns (PM2.5), fell approximately 40 percent for the third cohort of 2007-2011 compared to the first cohort of 1994-98. The study followed children from Long Beach, Mira Loma, Riverside, San Dimas and Upland.
Children’s lungs grew faster as air quality improved. Lung growth from age 11 to 15 was more than 10 percent greater for children breathing the lower levels of NO2 from 2007 to 2011 compared to those breathing higher levels from 1994-1998.
The percentage of children in the study with abnormally low lung function at age 15 dropped from nearly 8 percent for the 1994-98 cohort, to 6.3 percent in 1997-2001, to just 3.6 percent for children followed between 2007 and 2011.
That compares to 2.5 percent by age 18 for children from the first two cohorts who lived in cities with cleaner air, such as Lompoc and Santa Maria. Cuts in federal funding forced the researchers to exclude those cities in the last cohort and focus only on areas with heavier air pollution.
“Reduced lung function in adulthood has been strongly associated with increased risks of respiratory disease, cardiovascular disease, and premature death,” said Gauderman. “Improved air quality over the past 20 years has helped reduce the gap in lung health for kids inside, versus outside, the L.A. basin.”
The growing years are critical for lung development. The researchers are monitoring lung function in a group of adults who participated in the study as adolescents. So far they have not found evidence of a rebound after the teenage years.
“Their lungs may have lost the opportunity to grow any more,” Gauderman suggested.
Broad benefits from better air
Lung development measured by the study improved across the board, regardless of education, ethnicity, tobacco exposure, pet ownership and other factors.
Across all five communities, lung development for children with asthma improved roughly twice as much as for other children. But even children without asthma showed significant improvements in their lung capacity, suggesting that all kids benefit from improved air quality.
“We expect that our results are relevant for areas outside southern California, since the pollutants we found most strongly linked to improved health — nitrogen dioxide and particulate matter — are elevated in any urban environment,” Gauderman said.
The incidence of asthma did not change significantly over the three cohorts. Previous research by the Children’s Health Study showed that the risk of asthma increases with proximity to busy roadways.
Lung function testing took place in school at least three times for each cohort, when the children were approximately 11, 13, and 15 years old. Students were asked to blow into a spirometer, an instrument that measures lung size and strength. The spirometer reads total lung volume as well as the amount of air that a person is able to blow out in one second.
Air quality monitoring stations in the five communities took continuous readings of key pollutants over the study period, which the researchers averaged to examine the exposures for each cohort.
Southern California cleans up
Local, state and federal regulations have achieved large reductions in pollutants in the Los Angeles basin.
In 2011, the concentration of NO2 was below the federal standard throughout the basin. PM2.5 was below the federal standard over most of the basin, and near the standard in a small area straddling Riverside and San Bernardino counties. However, the federal standard was lowered in 2012, leaving the five communities in the study at or slightly above the new standard.
Ozone was below the federal eight-hour standard for most of Los Angeles and the coastal basin and exceeded the standard fewer than 20 days a year in the valleys, although parts of San Bernardino and Riverside counties continued to exceed the federal standard 40 to 80 or more days per year.
“It’s an environmental success story. The air has gotten much cleaner than it was in the past. I grew up here in the ‘70s. Even from Pasadena you couldn’t see the San Gabriel Mountains on a typical summer day,” Gauderman said.
Gains not guaranteed
Gauderman cautioned: “We can’t get complacent, because not surprisingly the number of vehicles on our roads is continually increasing. Also, the activities at the ports of L.A. and Long Beach, which are our biggest polluting sources, are projected to increase. That means more trucks on the road, more trains carrying cargo.”
“These gains really aren’t fixed,” added senior author Frank Gilliland, Hastings Professor of preventive medicine at the Keck School. “We have to maintain the same sort of level of effort to keep the levels of air pollution down. Just because we’ve succeeded now doesn’t mean that without continued effort we’re going to succeed in the future.”
Gilliland noted that the state’s historic drought is expected to raise particulate pollution.
The study’s third cohort of 2007-11 also came of age at a fortunate time for respiratory if not financial health. The economy shrank and emissions fell during the Great Recession.
But the study also shows that air pollution and growth can coexist over the long term. The economy and population in the basin have grown since the cohort of 1994-98.
“Our results suggest that better air quality in future will lead to even better lung health,” Gauderman said.
Gauderman’s and Gilliland’s co-authors were Robert Urman, Edward Avol, Kiros Berhane, Rob McConnell, Edward Rappaport and Roger Chang, all from the Department of Preventive Medicine at the Keck School, and Fred Lurmann of Sonoma Technology, Inc.
The authors dedicated their paper to the late John Peters of the Keck School’s Department of Preventive Medicine, who conceived the Children’s Health Study and directed it over most of its 20 years.
The study was funded by the Health Effects Institute, a partnership of the auto industry and the federal government; the California Air Resources Board; the Hastings Foundation; and the National Institute of Environmental Health Sciences (grants ES011627, ES07048, and ES022719).
Sources: New England Journal of Medicine
Final 2012 Air Quality Management Plan, South Coast Air Quality Management District
California Regional Haze Plan, 2014 Progress Report (Appendix C), Air Resources Board of the California Environmental Protection Agency
The Community Outreach and Engagement team at the USC Environmental Health Centers has developed an infographic, the first in a series that we will be sharing with you over the next few months and years. This infographic has been developed especially for people who want to learn more about how their health is affected if they live or go to school in an area with lots of traffic pollution, near a busy road or traffic corridor. The infographic provides direct links to research studies done by USC Environmental Health researchers as well as other important studies on this topic.
Click on the image above to go to the interactive infographic. If you have more questions and want to learn more about the content of the infographic, please email us (scehsc (at) usc . edu) or visit our Facebook page and post a comment.