Were the French breathing better because of the Olympics?
Were the French breathing better because of the Olympics?
Olympic host countries often make improvements in preparation for the games. Can reducing pollution make their citizens healthier?
Organizers of the Olympic Games in Paris aimed to “cut the carbon footprint of the Games in half compared with previous editions” and host the “greenest-ever” international event. For example, plans for the Olympic Village constructed just outside of Paris focused not only on the athletes’ needs during the Olympics, but on what the residential facility can provide to the local community after the games are over: 2,500 homes, office and retail space, and ample parks and greenery built to accommodate a future with climate change. Thousands of trees were planted throughout the city, and numerous other interventions were taken to add greenery and promote pedestrian and bicycle activity over vehicular travel.
These efforts are part of a larger push by the International Olympic Committee to focus on minimizing environmental impacts and promoting long term environmental sustainability for the host cities. In addition to the future-minded Olympic Village, Paris took the games as an opportunity to make a variety of long term improvements to the city and its communities. This included efforts to clean up the Seine river, in which swimming has been banned for over a century due to pollution, to the point that bacterial levels were low enough to host the swimming portion of the Olympic triathlon (though some triathaloners fell ill, it’s not believed to be due to bacteria in the Seine).
These, along with a variety of other environmental, social, and economic programs that were part of the Paris 2024 Olympics may indeed improve health for the local population; only time will tell for Paris, but similar programs have had mixed results for prior host cities. But a growing body of research on prior Olympics—natural experiments that take advantage of the rapid changes made in preparation for the games—can tell us what some of those health benefits might be.
What were impacts on air pollution from prior Olympics?
We’re going to focus on air pollution and the measurable impacts it can have on human health, which has been shown to be wide-ranging. There are the more obvious impacts of poor air quality like asthma and other breathing problems, and less obvious ones like heart attacks, strokes, low birth weight, and death from all causes. A number of clever researchers over the past several decades took advantage of the natural experiments brought on by sudden major changes that impact entire populations all at the same time—what we might call an as-good-as-randomly-timed “shock to the system”—because of the Olympics.
Beijing 2008
Air pollution has long been an issue in Beijing, but organizers of the 2008 Beijing Olympics took a number of measures to improve air quality (many of them temporary, like pausing high-emissions industrial operations or limiting who was allowed to drive a car) during the games in August and September of 2008. These efforts worked, with various air pollutant levels dropping by 20-60% in the weeks leading up to the Olympics.
In a study of pregnant mothers that took advantage of the random timing of the Olympics relative to when mothers would be giving birth, researchers in China and the U.S. analyzed birth weights of 83,672 full term births that occurred in Beijing around the time of the 2008 Olympics (birth weight is a common public health metric, since low birth weight is associated with short- and long-term health problems, and air pollution has previously been shown to reduce birth weight). The study found that babies who spent the 8th month of their gestational period—when significant growth occurs—during the 2008 Beijing Olympics had a higher birthweight (by 23 grams) than babies born on those same calendar dates in 2007 or 2009 when pollutant levels were higher.
Another study of about 200 randomly selected Beijing residents measured lung function before, during, and after the Beijing Olympics, finding that airflow on exhalation (which can be impacted by air pollutants) increased in 78% of subjects during the Olympics compared to before the Olympics, and then it worsened in 80% of them after the Olympics were over and pollution control methods had stopped.
Air quality in Beijing has improved significantly since the 2008 Olympics, which seemed to have served as a catalyst for ongoing projects to address air pollution that have continued—such as a large urban forestry project we visited in an earlier post.
Atlanta 1996
Organizers of the 1996 summer Olympics in Atlanta, Georgia were also worried about air quality, which had historically gotten worse in the summer months in Atlanta—suggesting air quality could be bad that summer even before the estimated 2 million visitors would arrive for the games. In preparation, Atlanta restricted automobile and delivery vehicle travel, encouraged changes in business hours and greater telecommuting (fire up the dial-up modem!), improved existing train systems and public transit, and created new temporary bus lines to both accommodate the crowds and reduce emissions of air pollutants.
In a study published in 2001, a group of university- and CDC-based researchers in Atlanta measured changes in air quality, vehicular traffic, and rates pediatric asthma exacerbations in Atlanta emergency departments in Atlanta in the time before, during, and after the 1996 summer Olympics. They noted significant reduction in the air pollutant ozone—which has been closely tied to increases in asthma exacerbations in children—as well as particulate matter and carbon monoxide (see figure below). They also saw the expected reduction in vehicular traffic. Indeed, the interventions to reduce air pollution levels worked (as they would 12 years later in Beijing).
What happened to the kids with asthma? Depending on which database they used, they saw a reduction in visits to Atlanta emergency departments for asthma ranging from 11% to 44%—with the 44% reduction being among the children covered by Georgia Medicaid (who would be expected to be more susceptible to air pollution levels compared to children covered by commercial insurance policies).
What about Paris?
Compared to Beijing in 2008, the city of Paris was starting with generally better air quality before the Olympics began, and predictions were that air quality would be acceptable based on historical trends for this time of year. Paris already had robust public transit options and is accustomed to receiving millions of tourists every year, but of course, the Olympics is different. As in past Olympics, vehicular travel was restricted, and additional free bus lines were established to get spectators to and from athletic venues.
In the air quality diagram below, with each rectangle representing the daily air quality index measured in the heart of Paris for the year 2024, we can see that after some rough days in January, air quality has been average (“moyenne”) for most of this year, though there happened to be some days with inferior air quality in the weeks leading up to the July 26th opening ceremonies (Jui = Juillet, or July). During the games which ended on August 11th (Aou = Aout, or August), there were some days with poorer air quality.
Now, we won’t read into this too much since some variation in air quality is expected, particularly in the hottest months of the year. Without seeing what happens over the next few weeks, it’s hard to know how this stacks up with prior years. It may be the case that despite some days with poorer air quality, this is was actually better than we otherwise might have expected this time of year.
As far as health outcomes for Parisians, we’ll wait to see if any French researchers take advantage of this natural experiment as more data roll in over the coming years. Beyond air quality, some of the programs focused on urban improvement and promotion of sports among the population may reap benefits—again, only time will tell.
In the meantime, we now look to the future as we prepare to host the 2028 Olympics here in the U.S. in Los Angeles—a city famous for, among other things, its air pollution.