June 17th, 2019

j r schrockGUEST COLUMN, John Richard Schrock, Education Frontlines


Visibility was so bad that some superhighways in Shaanxi and Henan Provinces had to be closed for several days. This brown haze was so heavy in my region that you could not see more than one city block away. In the U.S., we occasionally have car pile-ups when there is unexpected fog in a low area, but our fog burns off in a few hours of sunlight. This brown haze does not go away with the sun.

“How does this translate into English?” I am asked. “Smog” is the closest word we have, but it is not correct. Combined from “smoke” and “fog,” smog is man-made pollution where smoke, nitrogen or oxygen oxides, ozone, sulfur dioxides, or soot from burning of coal or agricultural stubble combines with moisture to form smog. When sunlight changes these primary pollutants into even worse chemicals, it becomes photochemical smog. Four decades ago, I can remember this air pollution that caused your eyes to water as you passed through Indianapolis or Cincinnati. The U.S. has greatly reduced this problem with regulations on the sources of pollution.         

But this brown haze is not smog produced by pollution in China. It is a natural airborne dust that would continue to tint the sky many days of the year even if no humans lived here. In Chinese, it is called wù mái [雾霾] and it is a fine dust that blows in from the north. The source is the Gobi Desert and the Loess Plateau. Loess (pronounced “luss”) is the geological name for such windblown soil deposits. These are smaller particles than sand and are unlike the sandstorms of North Africa or our Dust Bowl of the 1930s. The United States does not have exposed loess soils that are deposited by wind and can be lifted back up by wind. 

At the university in Yangling in Shaanxi, the skies are often bright blue when there has been a recent rain or when there is no wind.  But much of the time, the sky has a dull haze and the distant skyline of the Qingling Mountain range disappears. China is criss-crossed by mountain ranges. Without our wide-open plains, Chinese weather fronts are very “chopped up” and weather is local.

Western professors who come on academic exchanges may have a cough for their first month as their lungs get acclimated to this persistent dust. If your windows are open in the summer, you can wipe the furniture clean today and draw your finger through new tabletop dust tomorrow.   

Agriculturally, this continual loess deposit helps replenish nutrients and makes this region of China the origin of ancient agriculture. Today, this is still the center of agricultural research. The layers of loess also compress the underlying deposits into a compact material which on hillsides can be cut into durable cave houses, called yáo dòng [窑洞]; they have arched entrances and comfortable conditions inside.

The students on this agricultural university campus come from across China and adjust to the periodical heavy dust. But this last fall was particularly “dusty.” Over half of the students were wearing cloth face masks, called kǒu zhào [口罩], to filter out the dust.  These face masks are common in Japan and in large cities throughout Asia to reduce the exchange of airborne germs. But here, this high dust level drove many students to don a wide variety of fashionable face masks whenever they ventured outside the university buildings.

In these last two years, traveling to Beijing and back on the high speed train, I could see wide swaths of green plastic ground netting draped across any exposed soil. Whether it was a construction site being cleared for a new building, or the right-of-way at the side of a new road or railroad, if the soil was exposed and not being currently worked, it was covered by this ubiquitous green netting, called bǎo hù wǎng [保护网], literally "protection netting," that kept the wind from lifting up the dust. These sites were near China’s residential population and any airborne soil would have a closer impact on neighbors. I inquired, and yes, this was a new law. And since every bit of exposed soil in these developed areas was covered, that law is obviously enforced. 

As for the exposed surfaces of the massive Gobi Desert and the Loess Plateau, few people live there. That source of natural dust will continue---a problem China has that we don't have. 

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