There are major cities that, due to industrialization, geographic factors, and just sheer size, have a reputation for problematic air quality. Travelers to Beijing, Delhi, or Los Angeles are familiar with the air quality issues found in those cities–issues that can carry serious health implications for residents.

But what is not as commonly known is just how pervasive air pollution is. Even when planning a trip to a seemingly remote vacation getaway, it may still not be possible to escape the effects of poor quality.

Here are five of the world’s most famous vacation cities that also have some of the worst air quality on record.

Paris, France

Paris, Francehas a reputation that precedes it around the world: the Eiffel Tower, the Louvre, and the sumptuous cuisine of this vibrant European city drew over 30 million tourists every year prior to the COVID-19 pandemic.¹

But less known is that the air quality in Paris is among the worst in Europe. A 2016 study by the French health agency Santé Publique France found that nearly 48,000 people die in Paris every year from causes related to air pollution.²

How does such an iconic city fall prey to dangerous air pollution? There are a few reasons behind this.

First, Paris is an enormous business, financial, and professional center. Along with this concentration of power comes dense, daily commuter traffic. Thousands of cars emit exhaust into the city’s air each day – so much so that, when Paris implements its regular bans on cars driving through the city, the air becomes drastically cleaner.^3,4

In response to high concentrations of air pollution, Paris has implemented a phased system of driving requirements with increasingly higher emission standards necessary for entry into the city. Entry requires a sticker displayed on the vehicle indicating how much pollution the vehicle emits.⁵ By 2030, only electric and hydrogen fuel cell vehicles will be allowed entry.⁶

Next, many people still burn wood in their furnaces for heat during the winter. This creates a two-fold effect: burning wood emits dangerous ultrafine particles into the atmosphere, and the cold winter weather traps pollutants in the lower atmosphere, creating a temperature inversion.

Wood burning is also the target of many bans in Paris, most of which have been unsuccessful.⁷ However, the French government intends to reduce domestic wood burning and fine particle emissions, or PM2.5, by 50 percent through policy plans under development.⁸

So before you visit the city of lights and love, be wary of air pollution as you traverse Paris’ historic streets. Stay indoors during peak commuting hours and avoid indoor areas that burn wood for heat.

Yosemite National Park, California

Known for its idyllic wilderness and stunning, forested views, Yosemite, along with many other U.S. national parks, has perennial air quality issues.

Between its mountainous inland location and proximity to enormous wooded areas prone to wildfires, Yosemite often falls victim to vast plumes of wildfire smoke and other pollutants that get trapped in its numerous valleys and shroud its famous landmarks, such as the striking El Capitan peak and groves of giant sequoia trees, in a thick, dark haze.

And the annual summer wildfire season can cause air quality in Yosemite to skyrocket to unimaginable levels. In 2018, as smoke traveled south through Yosemite from the Carr Fire in Northern California’s Shasta County, Air Quality Index (AQI) measurements in Yosemite were regularly recorded over 300, which are considered emergency-level conditions that threaten the health of residents and tourists alike. At one point, Yosemite’s air quality was the worst in the United States, with an AQI measurement of 386.⁹

That same year, Yosemite Valley and the surrounding areas were declared ‘indefinitely closed’ in late July as the local Ferguson Fire burned over 90,000 acres in the region and as the Carr Fire broke records as the largest fire in California history.¹⁰

Wildfires also caused Yosemite Lakes to be the most polluted city in the U.S. during 2020.

Like many Californians do each year, prepare for the possibility that a fire can break out without warning when planning a trip to Yosemite. Use an air quality monitor to check in real-time for poor air quality conditions and to keep an eye out for long periods of hot, dry weather. When that’s combined with high winds and a lack of rain in local weather reports, this can lead to conditions for wildfires to break out.

Kraków, Poland

Poland is a go-to destination for students of European history, architecture, and nature. Many Polish towns contain remnants of Europe’s colorful medieval past as well as reminders of the country’s more recent occupation by the Nazi-controlled German government during World War II.

Kraków, Poland’s former capital and one of its oldest cities, is often on the top of the list for travelers who want to take in Poland’s unique, well-preserved European charm, with over 15.8 million tourists coming through each year.¹¹

But Kraków is also on another, much less desirable list – in 2017, it was included on a list of Europe’s 50 most polluted cities (along with 32 other Polish cities), mainly due to its reliance on coal stoves for heating during cold weather. Kraków was the 11th most polluted city in Poland that year and the largest among the listed cities.

The changes in air quality during cold snaps are immediately recognizable, too: within hours, a perfectly clear day becomes a whitish haze of PM2.5 and ultrafine particles as cold smoke gathers in the atmosphere, trapped by inversions, and people don air-pollution masks even just to walk down to the local market.¹²

And the pollution is often exacerbated by another nasty pollutant once the sun comes out: ground-level ozone, which forms when particle pollutants and gases react with heat from sunlight. In no time at all, the streets of Kraków are bathed in a thick pollution soup.

The people of Kraków have taken notice. Resident Anna Dworakowska gathered nearly 18,000 signatures on a petition to get the city government to pass legislation to ban not only home coal use but also commercial use in factories, who produce a majority of the coal emissions.¹³

To address these problems, the city is paying for low-income households to switch to central heating, while working to eliminate other coal and wood-burning stoves.¹⁴

Air quality in Kraków continue to be poor, as the city registered as having the third worst air pollution in the world on January 12, 2021 as reported by Notes from Poland.¹⁵

Though poor air quality continues to affect Kraków, public awareness is inspiring enormous strides towards the elimination of pollution sources altogether.

Sydney, Australia

Australia can seem like a paradise on earth: miles of sandy beaches, picturesque skylines along the coast, and no shortage of world-famous attractions, such as the Sydney Opera House.

But when you land in this iconic Australian metropolis of over five million people, you may notice an unwanted visitor: dense, hazy smog. For years now, Sydney has been battling against two significant threats to its air quality.

The first is PM2.5 and ultrafine particulate matter. These harmful airborne pollutants are produced not only by vehicles and factories within the city but also by controlled fires around the city intended to reduce the amount of dry brush that can fuel wildfires during hot periods.¹⁶

A 2020 study published in Environment International found that 24 percent of PM2.5 created by human activity in Sydney came from wood heaters. Vehicles contributed an additional 16.9 percent and power stations were responsible for 10.5% of human-created PM2.5.¹⁷

Though hazard reduction measures can help keep wildfire threats to a minimum, the resulting smoke can make local air quality hazardous. During 2018, the AQI in Sydney reached as high as 476 in some northwest areas of the city.¹⁸ Just to put that in perspective, the AQI only needs to reach 300 to be considered an “emergency,” and rarely do even infamously polluted cities like Beijing reach AQI levels that high.

During the 2019 to 2020 brushfire season, 33 people lost their lives and over 17 million hectares were burned.¹⁹ In addition, a 2020 study published in The Medical Journal of Australia found that 417 people died from brushfire related asthma attacks and a further 3,151 were admitted for heart and respiratory problems.²⁰

The next biggest air quality threat is ozone, generated by a combination of exhaust pollutants, soaring temperatures, and an absence of wind to disperse pollution.²¹ Sydney, like most of Australia, can get really hot, and ozone can develop quickly in such a huge city with millions of vehicles and industrial sites.

And the situation may not improve without some intervention: a 2018 study from the University of New South Wales in Sydney found that the city’s air quality is increasingly sending people to the hospital for respiratory conditions linked to PM2.5 and ozone.

Air quality in Sydney may worsen in tandem with man-made (anthropogenic) global climate change without further research and public policies developed around minimizing air pollution and protecting public health.²²

Seoul, South Korea

Home to the 4th-largest metropolitan economy in the world (following Tokyo, New York City, and Los Angeles), Seoulis a dreamland of urban living and tourism. Over 10 million visitors flock to Seoul every year, seeking diverse, world-class attractions like the Dongdaemun shopping district, the gorgeous views of Namsan Park, and the more solemn Demilitarized Zone (DMZ) between North and South Korea.

But as with any major city, air quality in Seoul can be problematic.

In addition to PM2.5, ultrafine particles, and ozone generated by heavy commuter traffic and industrial activity (especially from coal plants), Seoul faces air quality challenges unique to much of Asia.

One of these challenges is Asian dust, dust blown up from infertile, desertified land and industrial emissions that covers many parts of Asia, including Seoul, in a thick, dangerous haze that’s known to cause heart attacks and kidney disease.^23,24

And ironically, this phenomenon is most disruptive during the summer, and few things can ruin a vacation through South Korea’s bustling capital than air that you can’t breathe safely.

But Seoul has taken notice and thus taken steps to combat this threat to its appeal as a world travel destination: when air quality becomes toxic, the city offers free public transit to public employees to encourage them to avoid taking pollution-emitting cars and trucks through the bustling urban region.²⁵

And Seoul doesn’t plan to stop there: the South Korea Ministry of Environment intends to address the causes of much of its national pollution sources by reducing emissions from older vehicles and coal plants, introduce new clean-energy fuels, and replace diesel-powered public transit with newer, clean natural gas (CNG) vehicles.²⁶

In 2019, South Korea passed emergency measures after record levels of fine dust covered the nation.²⁷ Measures included installing air purifiers in classrooms and encouragements to purchase liquified petroleum gas vehicles – vehicles that produce lower emissions than standard gasoline and diesel.

Tips for clean air travel

Air quality is a global issue. Air pollution in major cities can have systemic effects around the world – due to worldwide wind currents and increasing anthropogenic pollutant concentrations, few places are truly free from the consequences of air pollution. But by taking public transportation or using clean fuel to heat the home, everyone can have a positive impact on global air quality the long run.

Almost every major destination in the world has some kind of air quality issue – some air pollution is inescapable. Yet there are steps that can be taken to reduce exposure to harmful airborne pollutants.

Here are a few pro travel tips to help provide clean air for all travelers:

• Keep an eye on your air quality.Bring anair quality monitor along while traveling to get live air quality readings of ambient air as well as 72-hour air quality forecasts for planning activities around local air quality.

• Create a personal breathing zone. Select a quality personal air purifier, preferably designed to supply clean air free of 99% of pollutant particles down to 0.003 microns. Many major travel destinations are significantly affected by tiny particles from vehicles, factories, and smoke from coal and wood – an effective personal air purifier controls these pollutants and more.
• Choose clean travel options. Many major cities and attractions have world-class public transportation. Opt for the bus, subway, bicycles, or rideshare programs instead of renting a car, which can not only add to expenses with gas and rental costs but also contribute to local air quality issues.

The takeaway

Poor air quality doesn’t have to stop travelers from having fun. Recognizing where pollution comes from and how to keep it from harming human health is a step towards taking control of valuable vacation time and staying safe during travels.