Recent research by Eco Experts on global levels of pollution for air, light and noise, ranks the most and least toxic cities in the world. Cairo tops the worst ten list, followed by Delhi, Beijing, Moscow, Istanbul, Guangzhou, Shanghai, Buenos Aires, and Paris. Los Angeles is the only American city in the top ten list and comes in tenth. On the other hand, Zurich is the cleanest city in the world.
Pollution, of all kinds, can have a real impact on the health and well-being of everyday people. According to the World Health Organization (WHO), 9 out of 10 people around the world breathe polluted air. We seem to just accept it now as part of life.
Furthermore, WHO estimates that about 7 million people die every year from exposure to fine particles in polluted air that penetrate deep into the lungs and cardiovascular system, causing diseases like stroke, heart disease, lung cancer, chronic obstructive pulmonary diseases and respiratory infections, including pneumonia.
We have always known that high pollution levels can have devastating impacts on both physical and mental well-being, leading to obesity, insomnia and depression. What is unique about the Eco Experts’ report is that it includes not just air pollution but artificial light pollution and noise pollution as well.
These last two have dramatic effects on sleep and circadian rhythms, which in turn have effects on mental and physical well-being in ways we did not understand until recently.
Poor sleep is indicated as a major cause of Alzheimer’s, Parkinson’s, and Lewy Body diseases as their associated build-up of specific proteins and peptides (short protein-like biomolecules), like alpha-synuclein and amyloid beta, occur when we do not have sufficient or quality deep sleep, particularly REM sleep.
Only during deep sleep are these cellular waste products cleaned out of our brains by specific neurological cells.
Since these neurodegenerative diseases are on the rise worldwide, affecting younger and younger people, light and noise pollution have become very important issues. Between 1979-2010, America had the worst increase in neurological deaths of any country – men up 66% and women up 92%.
The Eco Expert’s report used specific international definitions to rank these cities. The WHO defines air quality mostly based on two measures – PM10 and PM2.5. PM10 is particulate matter in the air that is 10 micrometers in diameter or less, and PM2.5 is 2.5 micrometers in diameter or less, often described as fine particles or aerosols.
The finer the particle the longer it is suspended in air, and the easier it is to become airborne in wind. It can be fine solid or liquid particles. Safe levels of PM10 are those under 20 ug/m3, while safe levels of PM2.5 are under 10 ug/m3.
The level of artificial light pollution at night for each city is measured in candelas per square meter (μcd/m2). As references, 1 μcd/m2 is the absolute threshold of vision and the natural night sky is about 174 μcd/m2.
The Mimi Hearing Index was used by the researchers to define noise pollution as a unitless number between 0 and 2, the closer to 2 the noisier the city.
This Eco Experts’ report names Cairo as the most polluted city in the world, scoring in the bottom three for air pollution (284 PM10), light pollution (14,900 μcd/m2) and noise pollution (1.7).
Chinese cities dominate the most polluted 10 – Beijing is 3rd, Guangzhou is 6th and Shanghai is 7th. Beijing scored badly for toxic air (73 PM2.5), the third highest air pollution score in the study and over 7 times the WHO safe level.
Los Angeles is the most toxic city in America, the tenth in the world, with the 7th highest PM10 air pollution levels at 57 PM10, and a light pollution score of 10,900 μcd/m2. Chicago and New York ranked in 21st and 26th place, respectively.
On the other side, Zurich, the largest city in Switzerland, is the cleanest city in the world, scoring in the bottom five across all pollution types, with light pollution levels of only 2,170 μcd/m2 and the lowest noise pollution of all cities studied, probably because the Swiss have a tradition of ‘Quiet Hours’, usually between 10 PM and 6 AM, noon to 1 PM and all day Sundays.
People in Switzerland must make an effort not to make undue noise, including bans on mowing the lawn, using power tools, playing music, or talking too loudly within these hours of quiet.
It is no coincidence, then, that Switzerland is also in the top ten list of the Happiest Countries in the World. And no coincidence either, that the ten cleanest cities in the world are also some of the happiest cities in the world.
We already know that filthy air, contaminated water and other polluted parts of our environment kill more people worldwide each year than almost everything else combined – smoking, hunger, natural disasters, war, murder, AIDS, tuberculosis and malaria. And this pollution costs us well over $4 trillion in annual losses, or 6% of global GDP.
China knows this better than any other country as they have three cities in this top ten list, and over 300,000 people die each year in China from toxic emissions coming out of coal-fired power plants alone. It is the main reason that China is breaking ground on a new nuclear power plant every month.
While civilization has undeniably increased overall lifespan and quality of life for billions of people, we still have a lot of work to do to clean up some of the collateral damage that civilization has caused at the same time.
