Ground-level ozone is still damaging your health

Air pollution, Los Angeles-style. Image: Getty.

Ground-level ozone is one of six major pollutants regulated nationally under the U.S. Clean Air Act. It is not directly emitted, but instead forms in the atmosphere through reactions between other pollutants from cars, power plants and industrial sources. Breathing ozone irritates the airways and can worsen respiratory diseases such as bronchitis, emphysema and asthma.

Regulation has reduced ozone levels across the United States over the past four decades, but exposure to ambient ozone still negatively impacts our health, well-being and productivity. In a recent article published in the journal Health Economics, I found that harm from ozone extends well beyond the high exposure levels and sensitive groups that have traditionally been studied. In fact, I identify negative effects of ozone exposure on the performances of intercollegiate track and field athletes under the relatively clean conditions common in the United States today.

These findings suggest that ozone exposure may be imposing harm on people even when they don’t end up in the hospital, and that much of the U.S. public may still regularly suffer some degree of negative impact from ozone exposure.

Hazardous even at low levels

Health researchers have long known that exposure to high levels of ozone is associated with acute negative health outcomes. These include premature death, compromised lung function and cardiovascular issues.

More recent studies have found evidence that ozone also has negative effects at lower exposure levels. For instance, ozone exposures below regulated levels have been shown to contribute to premature deaths and reduce productivity among outdoor agricultural workers. It is also important to note that ozone exposure affects people’s health by inflaming their airways even when functional effects are not measurable.

Ground-level ozone is formed by complex interactions of nitrogen oxides and volatile organic compounds in the presence of sunlight. As a result, ozone levels tend to be highest in summer months. My results are based on outdoor NCAA and NAIA track and field competitions which are held across the contiguous United States during the spring, when ozone levels tend to be below annual maximums.

Ground-level ozone forms through reactions between other pollutants in the presence of sunlight. Image: Minnesota Pollution Control Agency.

Across the approximately 1,700 outdoor track and field meets that I analsed, the average daily ozone concentration was only 33.47 parts per billion, which is well below ambient ozone levels regulated anywhere in the world. For instance, the current eight-hour average National Ambient Air Quality Standard for ozone in the United States is 70 parts per billion, and the current World Health Organization guideline is approximately 51 parts per billion.

But even at the low ozone levels in my study, and among a young and fit population of college athletes, I found consistent evidence that ozone had negative impacts on competitors in endurance events such as the 800 meter run, 3,000 meter steeplechase and 5,000 meter run.

Higher ozone levels, slower race times

Through the analysis of almost 700,000 competition outcomes in 277 different locations over nearly a decade (2005-2013) across the United States, I found that for every 10 parts per billion increase in ambient ozone levels, athlete performance was degraded by 0.4 per cent across endurance events. This effect represents more than five per cent of the average margin of victory in these races, and suggests that there was a 1.5 per cent difference in average athletic performance between the 5th and 95th per centile ozone days in the data.

For a concrete example, consider performances in the 5,000 meter run event. The mean finishing time for men competing in this event was 15 minutes 54.7 seconds. But at meets with average ozone levels above 50 parts per billion, the mean finishing time was 16 minutes 26.0 seconds. The comparable times for women were 19 minutes 5.7 seconds across all ozone levels versus 19 minutes 58.5 seconds at the higher levels.

I found these negative impacts of ozone were larger for longer events in which athletes competed over more extended periods. However, I did not find larger effects for athletes who competed in multiple events. Nor did I observe effects in events which do not heavily tax aerobic capacity.

Ozone in the stratosphere protects life on Earth from ultraviolet radiation, but at ground level it’s a toxic pollutant.

This makes sense because ozone exposure harms the airways and lungs, which are critical to performance in endurance events. They are less important in sprint events, in which muscles can rely primarily on stored energy reserves, or strength events such as the long jump or shot put, which test a single maximum exertion. While athletes in non-endurance events are undoubtedly harmed by ozone exposure, competitive outcomes in such events did not prove useful for studying the damage.

My findings point to risks for anyone spending time outdoors at current ozone levels. According to the U.S. Bureau of Labor Statistics, nearly half of all U.S. jobs require outdoor work. In 2004, nearly 27m Americans were employed in industry sectors in which at least some workers spent much of their workdays outdoors, such as construction, utilities and agriculture. The agency projects that this number will grow to nearly 31m by 2024, representing nearly 20 per cent of the U.S. workforce.


US standards under review

The Clean Air Act requires the Environmental Protection Agency to review and revise national ambient air quality standards regularly to ensure that they protect public health and the environment. Such reviews led to stricter standards for ozone in 1997, 2008 and 2015, lowering the regulatory threshold to 80, 75 and 70 parts per billion respectively.

The agency is currently preparing to carry out its next review of the ozone standard so that any updates can be finalised by October 2020. Earlier this year, then-EPA Administrator Scott Pruitt proposed changes to the review-and-update process that critics argue could weaken standards and threaten public health.

Deregulation advocates often emphasise the costs of complying with tightened regulations. For example, the EPA estimated that reducing the ozone standard from 75 to 70 ppb in 2015 would cost $2.2bn annually. Importantly however, the agency also projected that this change would generate health benefits worth between $4.1 and $8.0bn annually.

A global health risk

Today more than 105m Americans live in one of the 168 counties currently designated as part of ozone non-attainment areas due to violations of the current national ozone standard. The situation is worse in many emerging economies, such as India and China, where rapid industrialisation has led to high and increasing ozone levels.

Climate change is expected to contribute to increases in ozone levels by warming the atmosphere and extending the annual period of high ozone formation from summer into fall. These possibilities, along with findings like mine showing ozone’s impacts even at low levels, underscore the continued importance of effective global monitoring and regulation of ozone and its precursor pollutants.

The Conversation

Jamie T. Mullins, Assistant Professor of Resource Economics, University of Massachusetts Amherst.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

 
 
 
 

Could twin towns bring Britain back together?

An unlikely pair. Image: Wikimedia Commons.

Twin towns: an irrelevant novelty to most of us, a peculiar name on a village’s welcome sign. But could linking one British town to another – a domestic reinterpretation of this long-standing European practice – help bring Britain back together in a time of national crisis?

Born in the aftermath of World War II, town twinning aimed to foster cooperation and solidarity across Europe. Communities entered formal alliances, nurturing friendships and shared histories. Coventry forged links with Dresden and Volgograd, then Stalingrad, marking the devastation faced by their citizens during the war.

The democratisation of Greece, Spain and Portugal during the 1970s led to a new wave of twin towns across Europe, as did the fall of the Soviet Union a decade later. Since its inception, the focus of town twinning has been on uniting people through relationships. It is a testament to the initiative’s success that many of these remain to this day; Coventry recently enjoyed a performance at the city’s cathedral by Volgograd’s children’s choir.

While European relations have improved since the 1940s, unity at home has received less attention. As a result, Britain is riven with deep economic, political, educational and cultural divides. These fault lines are increasingly determined by geography, with a growing gap between our big metropolitan cities and almost everywhere else.

In comparison to other European countries, we face staggering levels of regional inequality; six of the ten poorest regions in northern Europe can been found in the UK. As outlined by Alan Milburn, the government’s former social mobility tsar, “the country seems to be in the grip of a self-reinforcing spiral of ever-growing division. That takes a spatial form, not just a social one.”

These divisions are poisoning our body politic. As Adam Smith argued in The Theory of Moral Sentiments, putting yourself in someone else's shoes is vital for developing a moral compass; in doing so "we conceive ourselves enduring all the same torments, we enter as it were into his body, and become in some measure the same person with him..." But this is difficult when we have little interaction or experience of those with opposing views.

This is increasingly likely in geographically polarised Britain, with the places we live dominated by people who think alike. Our political leaders must commit time and energy to bridging these divides, just as the leaders of Europe did in the aftermath of the Second World War. By forging links between different parts of the country, a new era of domestic town twinning would do just that.


School exchanges between sister towns would offer an opportunity for children to be exposed to places, people and perspectives very different to their own. This would allow future generations to see things from an alternative and opposing perspective. It may also embed from a young age an awareness of the diversity of experiences seen by people across our highly unequal country.

MPs would be encouraged to spend time in their constituency’s sister town. First-hand exposure to voters in a very different part of the country would surely soften the views of even the most entrenched parliamentarian, making for a more civil debate in the Commons. Imagine the good this would do for Parliament today, with Brexit gridlocked because of the unwillingness of MPs to compromise.

In 2016 the Carnegie UK Trust launched its Twin Towns UK programme, a pilot linking twenty towns across the UK to examine how they might develop together. Emerging benefits include a reduction of insularity and a greater awareness of the bigger picture. Its focus was not on bridging economic divides – towns with similar socioeconomic characteristics were twinned – but initial outcomes from the scheme suggest a broader programme of domestic town twinning could have a powerful impact.

Looking further back, Camden has been twinned with Doncaster since the 1980s, a relationship that unionised Camden Town Hall workers forged in a display of solidarity with striking miners during the 1980s. Funds were raised to feed families of striking workers at the pit and Camden locals even drove north to deliver presents at Christmas. Though the relationship appears less active today, it serves as a powerful reminder of twinning’s capacity to bring people from very different places together.

As we prepare for Brexit it’s imperative that we protect existing twin town relationships with our European partners. This is of vital importance when we know sadly many of these are under threat from austerity and gloriously un-PC mayors. But we should look to breathe new life into these traditions too, where possible. Domestic town twinning would do just that: a step towards bringing Britain back together, just as a continent was reunited after the devastation of war.

Ben Glover is a researcher at the think tank Demos.