When the world gets closer.

We help you see farther.

Sign up to our expressly international daily newsletter.

Already a subscriber? Log in .

You've reached your limit of one free article.

Get unlimited access to Worldcrunch

You can cancel anytime .


Exclusive International news coverage

Ad-free experience NEW

Weekly digital Magazine NEW

9 daily & weekly Newsletters

Access to Worldcrunch archives

Free trial

30-days free access, then $2.90
per month.

Annual Access BEST VALUE

$19.90 per year, save $14.90 compared to monthly billing.save $14.90.

Subscribe to Worldcrunch

Why Summer Should Always Remind Us Of The Ozone

With the arrival of the heat, it can seem that air pollution has increased. But is this just our perception or reality?

Why Summer Should Always Remind Us Of The Ozone

The summer heat increases the levels of tropospheric ozone.

Mariana Toro Nader


MADRID — In summer, days are longer and people are more eager to be outside, but does that also increase environmental pollution? In truth, it's not a matter of perception: the summer heat increases the levels of tropospheric ozone, one of the polluting gases with the highest impact in Spain and across the planet.

Ozone (O3) is a colorless, odorless gas that, depending on which layer of the atmosphere it is in, can have either positive or negative effects. Stratospheric ozone is the "good" ozone, found 10 to 50 kilometers above the earth's surface. There, it forms the so-called ozone layer, which protects living beings from the sun's ultraviolet radiation. When this layer degenerates, it creates ozone holes that can contribute to global warming, as well as increase the risk of skin cancer, eye cataracts and affect people's immune system.

However, when ozone is in the troposphere — the layer of the atmosphere closest to Earth — it becomes a byproduct pollutant produced by primary pollutants such as nitrogen oxides (NO and NO2) and volatile organic compounds.

Tropospheric ozone is hazardous to our health: it affects the respiratory system, causes throat, eye and mucous membrane irritation, can trigger coughing and can reduce lung function. It makes breathing more difficult, increases cases of asthma attacks, and can worsen other chronic lung diseases such as emphysema and bronchitis. In addition, it is associated with increased deaths due to cardiovascular failure.

The people most vulnerable to high ozone exposure are children under six years old, people with pre-existing conditions such as chronic respiratory or cardiovascular problems, and the elderly. However, it is also recommended that pregnant women, oncology or polymedicated patients and immuno-compromised persons take extreme precautions when temperatures rise and, therefore, ozone levels increase.

Consequences of "bad" ozone

In addition, it also has a toxic effect on ecosystems. This type of ozone can damage forests and vegetation, impacting the photosynthesis process, thus reducing the plants' absorption of carbon dioxide and, as a result, leading to a reduction in biodiversity. It also affects agricultural yields.

There's also an increase in flights and traffic due to vacations, as well as a spike in electricity production.

Three years ago, 59% of forested areas and 6% of agricultural land was exposed to harmful levels of tropospheric ozone on mainland Europe and, in 2019, economic losses due to O3 effects on the wheat crop were estimated at €1.4 billion in 35 countries, according to European Environment Agency (EEA) data.

According to the EEA, air pollution is the biggest environmental health risk in Europe. In 2020, 96% of the EU's urban population was exposed to ambient concentrations of fine particulate matter above the WHO guideline standard of 5 micrograms per cubic meter of air. The agency estimates that poor air quality causes at least 238,000 premature deaths in the EU.

The only effective way to reduce surface ozone levels could be to eliminate or reduce its sources, i.e., reducing traffic and industrial activity.

Aleksandr Popov

In search of a solution

So what can be done to help? Catalonia's Climate Action Secretariat states that the only effective way to reduce surface ozone levels is to eliminate or reduce its sources, i.e., reducing traffic and industrial activity. Together with carbon dioxide and methane, ozone is one of the major greenhouse gases.

Not only does heat act as an activator of O3, but in the summer there is also an increase in flights and intercity traffic due to vacations, as well as a spike in electricity production in thermal power plants because of more air conditioning being used.

This is especially worrying considering that the world is getting hotter and heat waves will become more extreme and recurrent, as the Intergovernmental Panel on Climate Change has warned. Since the late 1970s, Earth has recorded average temperatures above the 20th-century average every year.

And just last month, the record for the hottest day ever recorded around the world was broken — three times in one week.

You've reached your limit of free articles.

To read the full story, start your free trial today.

Get unlimited access. Cancel anytime.

Exclusive coverage from the world's top sources, in English for the first time.

Insights from the widest range of perspectives, languages and countries.


The Problem With Always Blaming Climate Change For Natural Disasters

Climate change is real, but a closer look at the science shows there are many factors that contribute to weather-related disasters. It is important to raise awareness about the long-term impact of global warming, but there's a risk in overstating its role in the latest floods or fires.

People on foot, on bikes, motorcycles, scooters and cars navigate through a flooded street during the day time.

Karachi - People wade through flood water after heavy rain in a southern Pakistani city

Xinhua / ZUMA
Axel Bojanowski


BERLIN — In September, thousands of people lost their lives when dams collapsed during flooding in Libya. Engineers had warned that the dams were structurally unsound.

Two years ago, dozens died in floods in western Germany, a region that had experienced a number of similar floods in earlier centuries, where thousands of houses had been built on the natural floodplain.

Last year saw more than 1,000 people lose their lives during monsoon floods in Pakistan. Studies showed that the impact of flooding in the region was exacerbated by the proximity of human settlements, the outdated river management system, high poverty rates and political instability in Pakistan.

There are many factors that contribute to weather-related disasters, but one dominates the headlines: climate change. That is because of so-called attribution studies, which are published very quickly after these disasters to highlight how human-caused climate change contributes to extreme weather events. After the flooding in Libya, German daily Frankfurter Allgemeine Zeitung described climate change as a “serial offender," while the Tageszeitung wrote that “the climate crisis has exacerbated the extreme rainfall."

The World Weather Attribution initiative (WWA) has once again achieved its aim of using “real-time analysis” to draw attention to the issue: on its website, the institute says its goal is to “analyse and communicate the possible influence of climate change on extreme weather events." Frederike Otto, who works on attribution studies for the WWA, says these reports help to underscore the urgent need for climate action. They transform climate change from an “abstract threat into a concrete one."

In the immediate aftermath of a weather-related disaster, teams of researchers rush to put together attribution studies – “so that they are ready within the same news cycle," as the New York Times reported. However, these attribution studies do not meet normal scientific standards, as they are published without going through the peer-review process that would be undertaken before publication in a specialist scientific journal. And that creates problems.

Keep reading...Show less

The latest