Mapped: Which Countries Have the Worst Air Pollution?

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In many parts of the world, blue skies are a rarity. Instead, accumulated levels of air pollution from industrial processes and motor vehicle traffic cloak cities in smog year-round.

But to what extent does air pollution impact the human population around the world?

To answer this question, data scientist Matt Dzugan has created a cartogram that shades each country based on levels of fine particulate matter (PM2.5) air pollution experienced by the population living there.

Carto-What?

First off, let’s talk about the visualization style itself.

Not your everyday map, this unconventional cartogram resizes the borders of countries based on their total populations. In this style, a single square represents 500,000 people. According to Matt Dzugan, the cartogram view is meant to provide a bird’s eye perspective of the impact of air pollution and fine particulate matter (PM2.5) on human lives.

A clear correlation emerges: some of the most inhabited places in the world also experience the most pollution. Highly populated China and India show up the most prominently, while other countries like Australia and Canada seem to disappear off the map entirely.

To put this into perspective, 800 dark brown squares on this cartogram (a PM2.5 concentration of 50 μg/m³) represent 400 million people in India that are exposed to polluted air at levels five times past thresholds set by the World Health Organization.

Top 20 Countries with Cleanest Air

So how do countries on each end of the PM2.5 spectrum shake out? Pulling supplemental data from the WHO, here’s how the top 20 countries with the cleanest air rank.

New Zealand tops the above list. And as you can see, air quality tends to be highest in advanced coastal economies with low population densities—and being an island or bordering less habitable Arctic tundra also helps as well.

That said, there are temporary bouts when air quality can dip in even the best of countries. For example, recent wildfires on the West Coast of the United States and Australia resulted in reddish-orange skies and hazardous levels of air quality for weeks at a time.

The 20 Countries with the Most Air Pollution

On the other hand, it may be surprising that Nepal lands all the way at the bottom of the air quality list. Why is this landlocked country—home to less than 30 million—suffering from hazardous air pollution reaching 100μg/m³?

In short, the emissions from fossil-fuel driven traffic and manufacturing operations are trapped within the Kathmandu valley, which causes air quality issues for people living in the region.

The regions with lower air quality tend to be more landlocked with developing economies, such as some countries in central Africa and Asia, as well as in the Middle East.

Finally, while China is lower on this overall list, it’s worth noting that it is one of the most prominent on the cartogram due to its sheer population size.

The Most Valuable Real Estate Cities in America

According to real estate tycoon Harold Samuel, there are three things that matter when it comes to real estate value—location, location, and location.

America’s property market is no exception to this rule. Depending on the city and its—you guessed it—location, there are vast discrepancies in real estate value across the country.

Usingthe latest data from LendingTree, this graphic ranks the top 30 most valuable real estate cities in America. We’ll also evaluate the top cities based on median value of homes, and how COVID-19 has impacted the market.

The Most Valuable Real Estate Cities

Out of the $32.6 trillion of total real estate value included in LendingTree’s database, the top 30 cities account for almost 57%:

New York has the highest real estate value in the country at $2.8 trillion—that’s around the size of the UK’s GDP in 2019. Close behind is Los Angeles at $2.3 trillion, while San Francisco ranks third at $1.3 trillion.

This may not come as a surprise, considering the popularity of these areas. New York and Los Angeles have the two highest city populations in the U.S., and San Francisco is the second most densely populated city in America (after New York). Historically, these areas have been notorious for their red-hot real estate markets, limited housing supply, and high costs of living.

However, while these cities take the top three spots when it comes to total real estate value, the ranking looks a bit different when comparing the median value of each city.

Most Valuable Cities, by Median Home Value

When it comes to median home value, San Jose claims the top spot at $1.1 million, while San Francisco places second at $959K:

The Bay Area leads the pack in terms of median value, but San Francisco and San Jose aren’t the only Californian cities to make the list. In fact, half of the top 10 cities are in the Golden State.

Suburban Shuffle

It’s important to note that these numbers are from January 2020, before the global pandemic triggered numerous societal and economic changes, including an accelerated migration to the suburbs from key urban centers like New York and San Francisco.

This mass exodus has negatively impacted sales activity. In fall 2020, or example, home sales in New York dropped by 50% compared to last year.

In contrast, places like Honolulu have seen significant growth in home sales—in September 2020, single-family home sales rose by 12.7% compared to last year. Some experts believe COVID has been a key factor driving this growth, as more people are able to work from anywhere, thanks to remote work.