Strangely, it turns out that the dust storms and the sulfur from power plants engage in a yin-yang like balancing act that somehow protects the city from toxic acid rain.
From Discovery News:
The Olympics put Beijing's ridiculous pollution problems on the world stage. It was common knowledge that China is a polluted place, but the smog-filled days leading up to the games genuinely surprised the world at large.
March 31, 2009 -- Powerful dust storms that whip across China's north and central deserts are infamous for blotting out the skies over Beijing. They wreak havoc with transportation and industry, and pose a serious health risk to the 17 million people who live there.
But they may be a blessing in disguise. According to a new study, the dust is protecting the city from a horrible case of acid rain.
And government reforestation and farmland management programs may be backfiring, inviting corrosive precipitation into the country's capital region.
Acid rain is a known scourge in China's heavily industrialized southern and northeastern reaches, threatening soil quality, forests and food supplies.
But for all its smog-ridden reputation, Beijing remains comparatively acid-free; an island amid the country's sea of coal-burning, sulfur-belching power plants. The reason is the region's regular dust storms. The calcium-rich dust acts as a buffer, neutralizing sulfuric and nitric acid particles before they fall to Earth.
"This is a time bomb waiting to happen in China," Gene Likens of the Institute of Ecosystem Studies in New York said. "Once you clean up the dust particles, all that material that was buffering and neutralizing the acidity is gone."Read On
But to anyone who'd visited China, let alone anyone who'd lived in China, the pollution problems exposed to the world were already common knowledge.
When people ask me about living in China (or in Xi'an particularly), I invariably tell them that pollution is the biggest drawback to being here. Waking up in the morning and walking out into acrid smoggy air is not something I'll ever get used to.
Xi'an, like Beijing, has out-of-control pollution. Xi'an's problem has a lot to do with the surrounding area's geography. Xi'an has exceptionally good feng shui. This can be seen in its name; "Xi" means "west" and "An" means "peace." Basically, Xi'an is considered a very safe and peaceful place because of it being in a cradle of the Qingling Mountains.
This Google Earth terrain map helps visualize Xi'an and its mountainous geography:
While these mountains give Xi'an good feng shui, they wreak havoc on Xi'an's air quality. The dust that comes in from nearby desertification and the pollution that comes from a fair bit of manufacturing in and around Xi'an makes for a pretty rancid mix. The pollution in and around Xi'an just stagnates in the city. It's awful.
The Google Earth terrain map that I just posted is helpful, but this Google Earth satellite photo of near where I live is even better for understanding Xi'an's pollution problem:
Notice the milky color here. That's the air. Not so nice.