The sun comes up, beaming its warmth on the ocean. Its energy gives life to powerful winds which circle eastward across the Northern hemisphere. The cycle is as old as the world. These days, though, the prevailing winds carry an undesired cargo: plumes of pollutants from the smokestacks of China. Of all China’s exports to North America, the deadliest is its air. North America struggles to improve its own air quality, only to have it destroyed by Chinese smog. The mechanisms of this air pollution problem are beginning to be understood but solutions are still a long way off.
China is a growth machine. Its average annual growth rate is an almost unheard of ten percent (Batson). The ruling communist party knows that only by growing gross domestic product (GDP) at this rate can it continue to provide an increasing quality of life for its very large, very poor population. Only by doing this can the party stay in power. China has always been prepared to keep growing at any cost.
Smog in Tianjin, China
Growth is impossible without energy. Most of China’s energy comes from coal-fired power plants. China uses more coal than the United States, the European Union, and Japan put together (Bradsher and Barboza). While it is one of the cheapest fuels, coal is also one of the dirtiest. As it burns it emits carbon dioxide, a greenhouse gas that causes global warming. Another byproduct is deadly sulfur dioxide gas, which causes about 400,000 premature deaths per year in China (Batson). Sulphur dioxide is also the primary cause of acid rain, which is currently experienced as far away as Korea and Japan. Finally, coal power plants produce fine particles of soot which dim the skies and produce health problems for all who breath them (Bradsher and Barboza).
China brings new power plants on line at a staggering rate. A new facility opens every week to ten days (Bradsher and Barboza). Between 2006 and 2012, China will build 800 new power plants (Zakaria 31). Even so, they have been hard pressed to meet demand during boom times. Chinese factories, faced with rolling blackouts, have installed small diesel generators. These units are often even dirtier than the coal plants they supplement. One benefit of the current recession is that it has given utility companies a chance to “catch up” and most private generators have been shut down, for now (Tran).
As China’s economy grows, so does its middle class. People who once lived in mud huts and cooked over dung fires are now moving into comfortable city apartments with computers, cellular phones, televisions and air conditioning. The number of air conditioners alone more than tripled between 2001 and 2006 (Barboza and Bradsher). Of course, all of these things require a great deal of electricity to build and operate. While these middle class Chinese still have a much lower energy footprint than their American counterparts, they use many times as much as their rural countrymen.
As much as the Chinese value their electronics and appliances, there is another status symbol for which they truly lust: the automobile. Only about ten percent of Chinese currently have drivers licenses, (Batson) but the rest will be driving soon. In 2007, China added about 14,000 cars to its fleet every day (Freidman 59). At this rate there will be 130 million cars in China by 2020. By 2050 (or perhaps even earlier) there will be more cars in China than in the US (Ibid).
The motorization of China is actively supported by the government, who see road building as a means of job creation and as a way to bring fast transportation to a big country. The Chinese government plans to expand its highway system to 53,000 miles of roads in 2020 The entire interstate highway system in the United States has about 47.000 miles of roads (Batson).
One of the primary byproducts of China’s growth pattern is air pollution. Coal plants, cars, and factories emit a plethora of undesirable by-products. Three of the worst of them, in terms of human health, are sulphates, particulates, and ozone.
Sulphates start out at the smokestacks of coal power plants as poisonous sulfur dioxide gas . When exposed to the atmosphere, the gas rapidly oxidizes to form particles of sulphate (Mickley 37). Some of the sulphate particles come into contact with water droplets creating acid rain. This sulphate laced water is corrosive enough to strip paint. It kills forests and crops and makes rivers and lakes unfit to sustain life. Most of it falls on China itself, but some is blown as far as Korea and Japan (Barboza and Bradsher). The solid sulphate particles are often blown as far as North America (Hotz). In the mountains of many West Coast states, the density of sulphate particles in the air already amounts to about one fifth of the maximum particulate concentration allowed by federal air quality standards (Barboza and Bradsher). Sulphate is also one of the major precursors to smog (Mickley 37). China emits more than 22.5 million tons of sulfur per year, accounting for one sixth of the world’s sulphate pollution (Barboza and Bradsher).
Another byproduct of coal combustion is black carbon. Black carbon is essentially very fine soot. When I first moved to Southern California I noticed how a fine black dust collects on any item left outside for more than a few hours. What I did not know until later was that over three quarters of the carbon dust pollution on the West Coast is directly traceable to China (Hadley et al. 1). The dust is more than just an aesthetic problem. Much of it is composed of respirable particles less than two point five microns in diameter. Particles of this size are dangerous because the human lung breaths them in easily but can not expel them again. Once lodged in lung tissue, they work their way deeper, contributing to cancer, respiratory damage, and heart disease (Bradsher and Barboza).
The other major ingredient in smog, besides particles like sulphates and black carbon, is ozone. Ozone is actually a good thing when it is found in the stratospheric ozone layer. It blocks harmful radiation that can cause skin cancer. When ozone is closer to the surface, however, it can cause big problems. Not only is it a smog precursor, but it is also highly reactive. Ozone molecules are “sticky”. They adhere to and damage human lung tissue and the leaves of plants. Ozone is not a direct emission of Chinese power plants or cars, but they do emit plenty of carbon monoxide, volatile organic compounds, and nitrates. When exposed to sunlight these chemicals react to form ozone (Mickley 36-37). Ozone, like particulates, then blows towards the West Coast on the prevailing winds, creating a ready-made “smog cocktail”.
The mechanism by which small particles are transported from Asia to North America has only recently been understood. For about a decade, scientists in the Sierra Nevada mountain range have been sampling the air in collectors. Analysis of the collected particles suggests an Asian origin. Other scientists notice a black haze over the pacific in satellite photos (Bradsher and Barboza). These observations led many to postulate the existence of high altitude “dust plumes”. It is believed that these plumes originate as clouds of natural dust in the Taklamakan and Gobi deserts of Central Asia. As the dust plumes blow east, they pick up particles of sulphates, black carbon, and other industrial pollutants (Hotz). As the plumes travel across the Pacific, they are lifted to high altitudes by cold fronts, where they are caught by fast moving winds (Hadley et al. 2). The particles in the plumes do not settle to the ground until they are slowed by the mountain ranges of North America (Hotz).
The dust plume theory was validated in 2006 when an international team of scientists, sponsored by the National Science Foundation, used a specially outfitted Gulfstream jet to systematically sample air over the Pacific. The study found new plumes every few days. The plumes form sinuous river-like structures high in the atmosphere. Some were as much as 300 miles wide and six miles deep–deeper than the Grand Canyon and wider than the Amazon (Hotz).
More recent research, such as the work of Prof. Ramanathan of the Scripps Institute, has used unmanned air vehicles (UAVs) instead of the more expensive jets. Because UAVs are much cheaper, they can fly more missions and produce more detailed maps of particulate distribution (National Science Foundation).
It is difficult to predict how the effects of the air pollution problem will change in the future. Most scientists agree that global warming will change world weather patterns, which will in turn change the distribution of smog. No one is quite sure how this will happen. One possibility is that a hotter atmosphere will be more stagnant. That is, there will be less air movement. This would tend to slow down the dust plumes and keep more smog closer to its source. Smog would get worse in Asia, but better in North America. In a more stagnant atmosphere, smog would also take longer to clear. Bad air quality events might last days longer than they do today (Mickley 39-39).
Whether smog stays in Asia or crosses the Pacific, warmer temperatures are likely to make it worse. Increased heat will accelerate the reactions that cause smog in the first place. The warmer the atmosphere becomes, the worse smog will become. Ironically, China’s air pollution might be slowing down global warming in the short term. China emits so many aerosol particulates like sulphates and black carbon that they actually block sunlight. It is estimated that the Chinese dust plumes currently block as much as ten percent of the sunlight over the Pacific (Hotz). This “global dimming” process is keeping the planet cooler than it would otherwise be. However, aerosol particles do not stay suspended in the atmosphere nearly as long as the greenhouse gases that causes global warming. Particles or no particles, global warming is coming and will intensify the smog problem (Bradsher and Barboza).
The Chinese realize that they have a serious air pollution problem. The central government in Beijing, spurred on by citizen activists, has unveiled a number of new policies to clean up their air. They have even had some initial successes. Beijing was able to host the 2006 Olympic Games partly because of its promises to clean up the city’s air quality. By delaying construction projects, closing factories, and only allowing cars to be used on alternate days, they achieved a substantial improvement by the time of the games. The programs worked so well that they decided to keep some of them in place after the games. Currently, drivers in Beijing are prohibited from driving for one day each week, based on their license plate number (Tran).
The pilot environmental programs that were begun during the Olympics were a good start. Even so, Beijing is still one of the most polluted cities on Earth. Beyond the capital, the central government has considerably less power. The provinces are largely governed by local politicians. These men are often involved financially with the same industries that they are supposed to be regulating. Not surprisingly, environmental regulations often tend to sporadically enforced (Bradsher and Barboza). China is so large, and the pollution is so bad, that it will take truly phenomenal efforts to clean it up.
Despite the scale of the problem, the Communist party has set ambitious goals in its most recent five-year plan. A number of the smaller and older coal power plants are scheduled to be decommissioned in the next few years. All of the remaining power plants must install scrubbing equipment by 2010. These scrubbers, which are standard equipment in the United States and European Union, remove most sulphates and nitrates at the smokestack (Bradsher and Barboza). New cars in China are now required to meet stricter emissions standards. Vehicles with larger engine sizes are taxed at a higher rate (Ho and Poon). It will be interesting to see how well China manages to enforce its new environmental regulations.
The air pollution problem in China is one of the biggest environmental challenges ever to face humanity. In the near future, the problem will probably get worse. While the pollution originates in China, high altitude dust plumes quickly transport it to North America and around the world. The Chinese government has begun to deal with the air pollution problem, but with limited success so far. Until the air pollution problem can be solved in China, efforts at healthy air in North America will ultimately be futile.
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