PARTICLE DICTIONARY

Smog has five main ingredients, which combined into a toxic cocktail. The tiny particles and harmful gases of the polluted air enter deep into the lungs, where they could cause anything from mild inflammation in the body to much more severe conditions such as dementia and diabetes.

provoke immune responses similar to those which cause Alzheimer’s and dementia in people.

CLIMATE AGGRAVATES SMOG

The toxic fog is not only a threat to people in China. Today, air pollution is one of the 10 leading causes of early death in the EU – only out distanced by typical lifestyle diseases such as elevated blood pressure, obesity, and adverse reactions due to smoking. British scientists also indicate that many people with fragile lungs are held hostages by air pollution. They neither can nor dare to venture outside, when particle values are too high. Although they may not die as a result of smog, pollution reduces their quality of life markedly.

However, the emissions that cause smog do not only harm our health, they also interfere with the world climate, altering precipitation and temperatures. The extremely high pollution rates in South East Asia weaken the vital monsoon, because pollution particles interfere with the process, by which humidity produces rain drops.

The effect is also reversed. In 2017, scientists showed that climate change contributes to aggravating China’s smog problems, when areas with toxic fog are more often and for longer periods of time held in place over the nation.

The reason is to be found far to the north, where sea ice is melting, affecting the weather systems of the more temperate regions of the world. Climate researchers have both predicted and observed how the Arctic is warming more than twice as fast as the rest of the world – and faster in the winter than in the summer. The phenomenon is known as Arctic reinforcement. During the winter, temperatures are now typically 5-10 degrees C higher in the North Pole region than 50 years ago. Instead of -40 degrees, the temperature

on a cold winter day is now -25-35 degrees C. That's actually pretty warm.

One of the systems affected by a warmer Arctic is the polar jet stream: a tremendous air current located about 60 degrees north of the Equator. The stream winds around the entire world about 10 km above sea level. The jet stream contributes to defining the boundary between cold and warm climates – a difference which also makes up the jet stream’s "engine". When the Arctic is heated fast, the temperature difference between the polar regions and the subtropics is reduced, causing the jet stream to lose momentum, so the twists of the stream tend to stop instead of continuing to flow west to east. So the same air mass remains in the same place for a long period of time, and can trap smog over a city for days.

WAR AGAINST SMOG PAYS OFF

China is entering its fourth year of the war against smog, and the struggle for clean air is already beginning to pay off. Although Beijing’s air quality remains alarmingly poor on some days, the number of days with acceptable air quality in 2016 was 198. In the same year, the level of hazardous PM2.5 pollution had fallen by about 10% as compared to the level in 2015.

The improvements have been made thanks to large-scale efforts by the authorities, which have established strict rules for the emissions

from anything from factories to motorists. Moreover, technology has lent a helping hand. Particle filters and chemical purification of smoke from diesel engines can remove some 90% of the harmful substances, before the smoke escapes the exhaust pipe. In power plants, sulphur is removed from coal, reducing smog by at least 60 %.

But most importantly, the government has realized that particle filters and sulphur removal are band-aids at best. The long-term solution involves halting the burning of coal and fuel in cities. So, China has allocated more than $400 billion to expanding renewable energy towards 2020, and toward putting more electric cars on Chinese roads than in any other place in the world. Before the Chinese know it, the problem could be solved, as the hazardous particles have very short lives in the atmosphere. If the pollution stops altogether, the air will clear in a few weeks or months to give Beijing its blue sky back.