Improved air quality in the Los Angeles region is linked to roughly
20 percent fewer new asthma cases in children, according to a USC study that
tracked Southern California children over a 20-year period.
The research expands on the landmark USC Children’s Health
Study, which found that children’s lungs had grown stronger in the
previous two decades and rates of bronchitic symptoms decreased as pollution
declined throughout the region.
“While the findings show a clear benefit of lower air pollution
levels, there must be continued efforts to reduce pollution in our region,”
said first author Erika Garcia, a postdoctoral scholar in the Department of
Preventive Medicine at the Keck School of Medicine of USC. “We’re
not in a place where we can stop and say, ‘Hey, we’ve arrived’.”
Los Angeles remains the nation’s most-polluted region, but
air quality improvements between 1993 and 2006 cut nitrogen dioxide pollution
by 22 percent and fine particulate matter by 36 percent.
Nitrogen dioxide can cause airway inflammation and airway
hyper-responsiveness. Particulate matter — tiny particles of soot, smoke dust,
etc. — can penetrate deep into the lungs and cause serious health problems.
To assess new-onset cases of asthma, USC scientists used
data from 4,140 children in nine California communities: Alpine, Lake Elsinore,
Lake Gregory, Long Beach, Mira Loma, Riverside, San Dimas, Santa Maria and
Upland. Parents or guardians completed questionnaires regarding their
children’s health. New-onset asthma was defined as a newly reported,
physician-diagnosed case of asthma on an annual questionnaire during follow-up.
Researchers looked at rates of new-onset asthma alongside
air pollution data collected from monitoring stations in each of those
communities during three different periods: 1993-2001, 1996-2004 and 2006-2014.
Using statistical methods, they separately examined four air pollutants and
found that two were associated with reductions in new-onset asthma. They estimated
that the nitrogen dioxide reductions achieved between 1993 and 2006 led to a 20
percent lower rate of asthma, while fine particulate matter reductions led to a
19 percent lower rate.
The findings add to the increasing scientific evidence supporting
the role of air pollution in the development of new cases of asthma. Asthma is
the most common chronic disease in children, affecting about 14 percent of
children around the world, and a major contributing factor to missed time from
school and work.
“This is encouraging news as it shows the number of new
cases of asthma in children can be reduced through improvements in air
quality,” said Kiros Berhane, a professor of preventive medicine at the Keck
School of Medicine of USC and one of the study’s authors. “This is very likely
a direct result of the science-based environmental policies that have been put
In addition to Garcia and Berhane, the study’s other authors
are Talat Islam, Rob McConnell, Robert Urman, Zhanghua Chen and Frank
Gilliland, all of the Department of Preventive Medicine at the Keck School of
The research was supported by the National Institute of
Environmental Health Sciences (grants P30ES007048, P01ES009581, R01ES021801,
and R01ES025786), the National Heart, Lung and Blood Institute (grant
R01HL118455), the United States Environmental Protection Agency (grants R826708
and RD831861), and the Hastings Foundation.
In June 2018, USC Environmental Health Centers
exposure assessment expert Rima Habre, ScD, contributed to a two-day
workshop hosted by the U.S. Environmental Protection Agency. Habre
discussed essential features, design recommendations and performance targets
specifically for wearable personal PM2.5 deployed in health research
studies to assess personal exposures and investigate relationships with health
outcomes in population studies. Dr. Habre’s presentation
discussed her work in the UCLA/USC Los
Angeles PRISMS center led by Dr. Alex Bui (UCLA Medical Imaging
Informatics) where researchers are developing a multi-sensor informatics
platform to enable mHealth studies of pediatric asthma. The platform, called BREATHE (Biomedical
REAl-Time Health Evaluation for Pediatric Asthma) allows researchers to monitor
environmental exposures, behaviors, medications and symptoms using Bluetooth-enabled
wearable sensors in real-time and in context, to ultimately help predict and
prevent asthma attacks in children. Dr. Habre’s presentation focused on ‘real-life
compatibility’ design and performance needs for low-cost PM2.5
sensors deployed as part of an informatics ecosystem, including flexible wear
options, battery life, communication needs, but also calibration well-suited
for mobile deployments on humans moving in and across microenvironments in
from the meeting that focused on performance targets for low cost sensors that
measure fine particulate matter and ozone, are summarized in a research
paper of which Habre is a co-author, published in April 2019 in the
Atmospheric Environment journal.
Williams, R., Duvall, R., Kilaru, V., Hagler, G., Hassinger, L., Benedict, K., Habre, R. … Ning, Z. (2019). Deliberating performance targets workshop: Potential paths for emerging PM2.5 and O3 air sensor progress. Atmospheric Environment: X, 2, 100031. https://doi.org/10.1016/J.AEAOA.2019.100031
information about the workshop, including links to all presentations, click here.
Learn more about Dr. Habre’s recent research here.
The landmark Children’s Health Study tracked thousands of children in California over many years—and transformed our understanding of air pollution’s harms.
Across Southern California, in school gyms and libraries and lunchrooms, the children filed in, one by one, to put their lips around a plastic tube and blow with all their might. Thousands of them, year after year, in rich neighborhoods and poor ones, from the breezy towns along the Pacific coast to the hot, smoggy valley locals know as the Inland Empire.
Erika Fields was one of them, back in the 1990s, when she was in high school at Long Beach Poly, just outside Los Angeles. Even now, she’s the kind of person who raises her hand, who steps forward when volunteers are needed, and she liked being the only one called out of her class, walking down the hall to the quiet room where the breathing machine sat on a desk. She liked, too, the sense of being part of something bigger than herself, something that might really matter in the world.
In the empty classroom, the woman from the University of Southern California would hand her a sterile mouthpiece, attached by a tube to the spirometer ready to gauge the power of her lungs. Erika would give it a couple of practice puffs to get comfortable before the one that counted. “I remember her saying ‘Push, push, push. Blow all the air out.’ And then she would show me on her laptop, and I could see on a graph where I pushed the most,” and watch the line edge downward as her breath tailed off.
After that, there was a survey to fill out, a couple of pages about her health and her family, about smoking in the home and pets and diet and exercise, and then Erika would walk back down the hall, back to her classmates and the ordinary rhythms of the school day.
She didn’t know it then, but those brief, once-a-year interruptions to her routine helped lay the foundation for insights that would ultimately change scientists’ understanding of what air pollution does to the human body. In the vast stacks of accumulating numbers—results from Erika Fields’s breath tests and thousands of others— a team of patient researchers would discern the outlines of a threat that had, until then, been hard to see.
Ed Avol was one of those scientists. He grew up breathing the foul air of 1960s L.A., and he remembers well the hacking coughs that filled the playgrounds of his childhood. An engineer by training, he worked early in his career on hospital-based studies that examined the effects of dirty air as researchers had for decades, by pumping pollution into small rooms and watching volunteers exercise inside.
The team he was part of wasn’t allowed to make conditions in their smog chambers any worse than what Angelenos would experience outdoors, but in the 1980s that still gave them plenty of latitude. The researchers would monitor subjects as they pedaled, measuring their heart rates and oxygen levels, making note of their coughing, their shortness of breath, and their red, watery eyes.
By that time, it was clear to scientists that ozone—the main ingredient in the smog that still plagues L.A. and so many other cities—had an immediate effect on those who breathed it. And the impact could be far more serious than the discomfort Avol saw so plainly: When ozone blankets a city, asthmatics wheeze, emergency room visits spike, and even in healthy people, the lungs can grow inflamed and struggle to do their job.
Read the rest of this article, including more of the history of the Children’s Health Study, and interviews from CHS investigators including Ed Avol and Jim Gauderman here on CityLab’s website.
On April 25, USC Community Engagement staff along with community partner Sandy Navarro from LA Grit Media began A Day in the Life program with youth from Pacoima Beautiful. The training kicked off the program during which youth from Pacoima will engage in community based air monitoring and storytelling through digital media. For more information on A Day in the Life click here.
This post was published on the Department of Preventive Medicine’s website as part of their National Public Health Week series. Please find the original post here.
Environmental health researcher Carrie Breton, ScD, associate professor of preventive medicine, has dedicated the last decade to studying how environmental exposures—like air pollution—early in life contribute to the increased risk of disease later in life. In this Q&A learn about her work as part of a maternal and developmental research center.
What area of public health does your work focus on?
I conduct research centered on understanding how early-life environmental exposures affect risks for cardiovascular, respiratory and metabolic diseases later in life. As part of this research paradigm, I have focused on exploring the novel roles that epigenetic changes may have in affecting susceptibility to environmental exposures such as air pollution and tobacco smoke.
What drew you the topic of environmental exposure in particular?
I have a fundamental interest in understanding how the environment affects pregnancy and the developing child.
In March 2019, youth participants from the Los Angeles communities of South LA and Wilmington, along with youth organizers from their respective communities and USC Environmental Health staff presented at the annual Citizen Science Conference, held this year in Raleigh, North Carolina.
The group presented during a workshop comprised of groups from around the country: Building Collaboration and Ensuring Justice in Community-Based Participatory Research: Lessons Learned from California, South Carolina, and Michigan.
The two youth who presented have shared the following reflections about their experience presenting and attending the conference:
Ashley Lazaro, 12th grade, South Central Youth Leadership Coalition
The highlight of my trip was having the opportunity to share my story with others and being able to connect with others that were dealing with similar situations. This trip taught me to be more assertive and to stand up for myself. I learned to not feel inferior or intimidated by anyone and that my voice as a youth is powerful.
To me citizen science means science or research that is conducted by the community itself. However, I do wish it was called people’s science to be more inclusive to my immigrant community. Citizen science gives me the opportunity to defend myself. Taking the research into my own hands gives me and my community power against big industries who try to make us feel inferior.
In the future I hope that the Day in the Life project can expand to more youth in the community. It was a helpful and fun project. Next time, people can journal their journey or it can be expanded to a week in the life.
Viridia Preciado, 12th grade, Communities for a Better Environment
The highlight of my trip was exploring a new place and exploring all it had to offer. What I took away from this trip was understanding that not only my community is going through all of this environmental racism, but others around the world are going through similar things. If parts of my community have came together to fight for environmental justice, why can’t the whole world do that to get what was once stolen from us. The right to clean air, water, soil, and so much more.
What citizen science means to me is the work and research done by individuals in our community to make that change and present it back to others to inform them. CBE may not use the term citizen science to describe our work, but it connects with our work because the community is really the ones who do all the work to mark a change in this world.
It would be great to involve more people to really experience this great program and to fully understand what it’s like to be in their community.
A recent research study by Dr. Rima Habre took a detailed look at
the short-term health impacts caused by breathing in ultrafine particulate
(UFP) matter that is emitted from aircraft activity at the Los Angeles
International Airport (LAX). Several years ago, USC researchers identified a
clear pattern of UFP emissions from takeoff and landing aircraft activities at
LAX. Levels of the dangerous UFPs were found to be 4 to 5 times greater than
background levels in downwind communities.
“Ultrafine particulate matter is known to contribute to reduced lung
function, and airway inflammation in individuals with asthma. We wanted to take
a close look at short term effects on health when individuals breathe air that
contains UFPs from airplanes,” said Habre. The study participants were made up
of adults with doctor diagnosed asthma.
Dr. Rima Habre has been with USC for five years. Dr. Habre’s
expertise lies in air pollution exposure assessment, analyzing patterns of how
people get exposed to air pollution across time and space and studying how
specific pollutants impact their health.
Recently Dr. Habre’s work reached the international stage through a documentary, produced by the Canadian Broadcasting Company, called Something in the Air. “The producers were very interested in learning more about our latest work around air pollution and asthma – specifically around the latest technologies we are using to better understand the impacts of small particles on a personal level – in children and adults with asthma, and in pregnant women.” Dr. Habre was interviewed about her work around ultrafine particle exposures downwind of major airports and its effects on asthma, as well as her work to understand how children’s personal exposure to air pollution predict their risk of experiencing an asthma attack. Something in the Air will be released this week in Canada, with an international release to be announced.
Airport-related ultrafines affect health differently than traffic-related
Habre and her team designed this study to test the short-term effects of breathing ultrafine particles by asking study participants to walk in a Los Angeles park located within the known higher levels of UFPs emitted from airplanes and near heavily trafficked roads, and another park farther away from the airport and busy roads with lower levels of UFPs.
“In our study, we found that inhaling UFPs led to higher
inflammation in the blood in adults with asthma shortly after exposure.
However, different inflammation markers responded to aircraft-related versus
traffic-related UFPs – both of which are major ultrafine particle sources in dense
urban areas. We were able to see these different signals because we managed to
overcome the challenge of separating the air pollution mixture into its major
sources using sophisticated measurements and modeling techniques,” said Habre. The pollutants measured by the study included
UFP particle number, particle size, black carbon, carbon dioxide,
particle-bound polyaromatic hydrocarbons, and ozone.
The significance of Habre’s study is that in such a short time,
following regular walking exposure and a higher exposure, they were able to see
significant elevation in inflammation systemically, not just in the lungs but
in the overall blood circulation. Inflammation is tied to a lot of disease
processes; cardiovascular, respiratory, and metabolic. “We don’t know
specifically what this inflammation will lead to down the line, but we know
that inflammation is generally a bad thing, and will complicate or exacerbate
existing conditions. Ideally, we would have liked to have been able to monitor
people long-term to see if that inflammation persists or if it goes down after
a while but we were not able to do that in this specific study, that’s a future
direction of this research I’d like to look at,” said Habre.
When asked what this research means to the overall population,
Habre described the current body of research that has found ultrafine particles
to be much more toxic than the larger sizes of particulate matter, UFPs are not
regulated, and UFPs impact large numbers of people who live in communities
Dr. Habre also leads environmental exposure assessment efforts in
multiple research studies being conducted at USC, including the MADRES
study of pregnant women and babies and the LA
DREAMERs study of children’s health across the life course, and in
partnership with other research groups such as the Los Angeles PRISMS
Center, a UCLA/USC partnership. Her work in the Los Angeles PRISMS
Center is taking a deeper dive into the different sources of air
pollution asthmatic children encounter in their day to day lives in Los Angeles
and how it impacts their health. This
study focuses on personal experiences, using Bluetooth-enabled wearable sensors
to monitor environmental exposures, location, activity, medications and
symptoms, to ultimately generate new information to help predict and prevent
asthma attacks. To learn more about the Los Angeles PRISMS Center, watch this
As she moves forward with her research on the health effects of
ultrafine particulate matter in urban areas, Dr. Habre plans to build on her
current work by studying how people with asthma are affected, as well as those
who are obese, have diabetes, or cardiovascular issues. “I would like to be
able to capture a wider variety of sources of ultrafines in urban areas and
also be able to monitor individuals for a longer period of time to really
understand what happens next. In this study we saw very quick and acute
effects, but do people tend to recover after a day? I think the ultimate goal
would be to really understand if people living in these high exposure locations,
for extended periods of time, and breathing this mixture in regularly are at a
significantly higher risk or not,” she said.
For more information on the “Something in the Air” documentary
that Dr. Habre’s work is featured in, on the documentary’s website: www.somethingintheair.ca.
Once the documentary is released in the United States, USC Environmental Health
Centers will publish the release date and viewing information.
Funding: This study was funded by the Southern California
Environmental Health Sciences Center (National Institute of Environmental
Health Sciences, P30ES007048) pilot program, NIEHS grants 1R01ES023262, 1K22ES022987,
1R01ES027860, and the Hastings Foundation.