I recall being pregnant and thinking in a completely hyper-focused way about every single thing that entered my body and what effect it might have on my growing child. I was pregnant during my pulmonary and Critical Care Medicine Fellowship, so in addition to working 80 hours a week, I was trying to find time to learn about all the important things that can affect pregnancy. One of the major concerns I wanted to avoid was preterm birth. Unfortunately, around 1 in 10 births in the US are born before 37 weeks, which increases a child’s risk of breathing problems, as well as developmental delay and impairments in other organs. It is also, scarily, the leading cause of death of infants, so I wanted to do everything I could as a young pregnant mother to avoid it. The work of Professor Beate Ritz was very helpful to me in understanding the role that air pollution exposure might play.
Dr. Ritz is an MD, PHD at the University of California Los Angeles. Her research focuses on the way our work and our environment can cause chronic diseases including neurodegenerative ones like Parkinson’s and developmental disorders like autism, asthma, cancer as well as poor pregnancy and birth outcomes. She has developed geographic information system based exposure assessment tools to study health effects of air pollution and of long-term pesticide exposures. She is currently directing the project on adverse birth outcomes as part of a satellite-based modelling effort for speciated fine particulates by the Jet Propulsion Laboratory. She is the 2007 recipient of the Robert M. Zweig M.D. Memorial Award from the California South Coast Air Quality Management District, and has served on multiple Institute of Medicine committees as well with the US EPA and a member of the Scientific Review Panel on Toxic Air Contaminants for the state of California. Professor Ritz has truly done groundbreaking research to help us understand the actual distribution of pollution in different lived environments as well as contributors from different sources. On the podcast, we talked about her research related to pollution and pregnancy, and she also has a whole body of work about pesticide exposure and health as well.
Many studies have shown relationships between air pollution from ground transportation and bad pregnancy outcomes in a variety of settings. Dr. Ritz has contributed significantly to this body of work starting in the late 1990s, with her studies looking at women who were pregnant and the carbon monoxide levels measured at nearby monitoring stations. As the carbon monoxide levels increased, the risk of premature delivery did as well.
Multiple other authors have found similar findings, and several meta-analyses (studies of many studies which combine the effects together), have shown that for every 10ug/m3 increase in PM2.5, risk of premature birth increases by around 15%. Other authors have shown that for each 10ug/m3 increase in PM2.5, birthweight decreases by close to an ounce (see references below).
Ultrafine particulate matter (UFP) which is less than 0.1 microns in diameter, also likely has significant health effects, but it can be hard to measure. Logically, it should have more of a health impact than PM2.5, since with even smaller particles, the increased effect of deeper body penetration and circulation should have more of a health impact. Dr. Ritz has been working with other researchers to study this as well. North Portland, where I work, has significant exposure to traffic related air pollution as well as being under an airport and near a port. Thinking about all those different potential sources of air pollution is important, and Dr. Ritz and other scientists did a study to understand both the risks of ultrafine particulate matter and living under flight paths to an airport.
The authors obtained birth records from 2008-2016 for mothers who lived within 15km of LAX (Los Angeles International Airport). They defined pre-term birth (PTB) as a live birth before 37 weeks, and excluded those with multiple births, missing data, etc, ending up with 174,186 births they were able to analyze. They then compared this to UFP matter emissions from airports (both modeled and directly measured as validation) to the addresses of the mothers to determine the impact on health. They controlled (that means accounted for) differences in NO2 from road-traffic as well as decibel levels for noise, and socioeconomic status.
They analyzed the data in multiple ways. No matter how they sliced it, increasing exposure to UFP was associated with an increased risk of premature births, as you can see below. The first column is the data for all mothers. The next categories show different adjustments or corrections, showing that this association at high levels (> 14,600 particles) remains even when accounting for age, race, education, socioeconomic status, cigarette smoking, NO2 and airport noise. The effect increased as the number of ultrafine particles increased.
TLDR= Don't Light Things on Fire and Breathe them into your Lungs
As a doctor, I spend my day helping translate science into the personal lives of my patients, helping them understand how different studies might apply to them, and what we and they can do to improve their health. One of the things that is so hard about air pollution is it is so often hard for us to control things as individuals unless we do have a lot of resources. Obviously, if we’re more well-off, we can buy houses in less-polluted areas far from the airport, or purchase electric cars, which will have benefits for our health and the health of our families. We can buy organic, live near parks, etc, but there are so many people who don’t have the ability to do that, who live, work, and raise their family in highly polluted environments. This comes at a huge cost to all of us. In 2007, the Institute of Medicine estimated that we spend $26.2 billion per year on the cost of preterm deliveries, or $51,600 per infant born preterm. I imagine that cost has increased over time in 2020 dollars. It is in all of our benefit to decrease preterm deliveries, and a sure way to do that, is to decrease air pollution.
It is important to understand the effects of these things as a community and to work for a day when everybody has a good shot at good health. Professor Ritz also demonstrates how important it is to have a variety of people engaging in science. On the podcast, she told me that she started to do her groundbreaking research about the effects of air pollution on pregnancy when she was pregnant herself, living in polluted air in Los Angeles, and realizing that nobody had done that science. Maybe there had just never been an air pollution researcher living in Los Angeles who was pregnant. This is why we need science at all levels to reflect the diversity of our communities so that science serves everybody in the community. Think of all the children and future adults that will benefit from the research that Professor Ritz has done leading to the policies she has helped inform to decrease pollution exposure to pregnant mothers. Think of the future money we will all keep in our pockets rather than spending on doctors visits and hospitalizations for people who are sick because they were born early due to air pollution.
Working in COVID19 has shown me how much of an anti-science trend there currently is in our society right now. Hard truths are hard to hear, so we want to not believe them, which makes people not want to believe the people who are delivering the bad news. Trust me, as someone who has to tell people regularly that they have cancer or that a loved one is dying, I am familiar with the denial, anger and grief that come from facing a hard truth. It is inconvenient that our current reliance on combustion engines for transportation sickens our communities. But it is important to face that hard truth, so we can move forward into a healthier and wealthier future by working for healthier air.
What can you do?
1- Be considerate about flying. Save money and air quality! Can you schedule that business meeting over video conferencing? Can you take a local vacation? Save up your flights for the truly important trips, like those to visit family or particularly extraordinary or important experiences.
2- Ask your community and local airport to be thoughtful about the total burden of air pollution being brought in. Consider actions like zero or low emissions airport shuttles and transportation, increased public transportation service to the airport, etc, to offset the burden of jet fuel in the area while we hope for future, cleaner air travel.
1- If you have a choice about where to live, consider flight paths to the local airport and whether there are ways to avoid them, balancing other health considerations.
2- Share your story as someone with lung disease, and the importance of breathing healthy air.
3- Learn more about asthma and biologic effects of exposure to jet fuel by listening to the first podcast with Dr. Matt Drake!
References-
Becerra T, Wilhelm W, Olsen J, Cockburn M, Ritz B. Ambient Air Pollution and Autism Risk in Los Angeles County, California. Environ Health Perspect. 2013 Mar;121(3):380-6
Ghosh JK, Wilhelm M, Ritz B. Effects of residential indoor air quality and household ventilation on preterm birth and term low birth weight in Los Angeles County, California. Am J Public Health. 2013 Apr;103(4):686-94
Ritz B, Yu F, Chapa G, Fruin S, Shaw G, Harris J Ambient Air Pollution and Birth Defects. Am J Epidemiol 2002; 155: 17-25.
Ritz B, Yu F, Chapa G, Fruin S Effect of Air Pollution on Preterm Birth Among Children Born in Southern California Between 1989 and 1993. Epidemiology 2000; 11: 502-11.
Wilhelm M, Ritz B Residential Proximity to Traffic and Adverse Birth Outcomes in Los Angeles County, California, 1994-1996. Environmental Health Perspectives 2003; 111(2): 207-16.
IOM Medicine report- cost of preterm birth
Kelly, Mike – photographer 2014. Source of “1 Day of Airplanes from LAX” photo– link photo for this entry
I’m glad it’s helpful! Trying to help people understand how the air we breathe impacts our health!