单项选择题

Car Pollution Jump in the car, start your engine and you’’re off. But do you give any thought to what’’s coming out of the tailpipe as you go about your drive Carbon dioxide is the dominant greenhouse gas that causes global warming. The effects of global warming are uncertain, but they potentially include disruption of global weather patterns and ecosystems, flooding, severe storm, and droughts. Carbon monoxide, when inhaled, combines with haemoglobin in our blood, impairing the flow of oxygen to our brain and other parts of the body. Carbon monoxide is colorless, odorless, and poisonous even to healthy people (at high levels). It can seriously affect people with heart disease, and can affect the central nervous system. Motor vehicles are the main source of carbon monoxide pollution in many countries. Sulphur oxides contribute to respiratory illness, particularly in children and the elderly, and aggravate existing heart and lung diseases. It contributes to the formation of acid rain, which damages trees, crops, and buildings; and makes soils, lakes, and streams acidic. Nitrogen oxide is a noxious pollutant. It is a lung irritant and reacts with compounds in the air to cause acid rain and ozone (the main reason for smog). Nitrogen oxide is one of the main ingredients involved in the formation of ground-level ozone (which can trigger serious respiratory problems), and contributes to global warming. Particulate matter, consisting of tiny particles of smoke, soot and dust primarily from engines, car parts, tires, and diesel exhaust, are an established cause of lung problems, from shortness of breath to worsening of respiratory and cardiovascular disease, damage to lung tissues, and cancer. The EPA estimates that particulate pollution kills more than 60,000 people per year. In addition, particulates are associated with increased hospital ad missions and emergency room visits for people with heart and lung disease, as well as work and school absences. Particulates can travel deep into the lungs, or in smaller form, directly into the bloodstream. Hydrocarbons, in their many forms, are directly hazardous, contributing to what are collectively called "air toxics." These compounds directly irritate the lung and other tissues, can cause cancer, contribute to birth defects, and cause other illnesses. Lead damages organs, affects the brain, nerves, heart, and blood. Although overall blood lead levels have decreased since 1976, urban areas with high levels of traffic or industrial facilities that burn fuel may still have high lead levels in air. In 1999, ten areas of the country did not meet the national health-based air quality standards for lead. Hybrid cars use less gas, and therefore produce fewer emissions, than conventional cars. Take a look at the statistics below (based on a car travelling 14,000 miles per year). ●A conventional car produces 11,100 pounds of CO2 per year, compared with the 4,800 pounds of CO2 produced by a hybrid car. ●A conventional car produces 330 pounds of carbon monoxide per year, compared with the 230 pounds produced by a hybrid car. ●A conventional car produces 49 pounds of nitrogen oxide per year, compared with the 17 pounds produced by a hybrid car. ●A conventional car produces 670 grams of particulate matter per year, compared with the 240 grams produced by a hybrid car. ●A conventional car produces 29 pounds of hydrocarbons per year, compared with the 8 pounds produced by a hybrid car. Rolling Up Your Window Won’’t Help Exposure to some car pollutants may be much higher inside your car than outside. Commuters driving in rush hour get the highest exposure, often from pollutants emitted by vehicles ahead of them. You are basically driving in and through -- and contributing to -- a lethal cocktail of air pollution. Other Impacts on the Environment When you think of pollution from cars, the first thing that comes to mind is noxious fumes. But the ,problems don’’t stop with air pollution. The environmental consequences associated with cars are much wider. Water Pollution Runoff of oil, automotive fluids, and roadway chemicals are estimated at hundreds of thousands of tons per year, and are considered the leading source of impairment to rivers. In addition, hundreds of thousands of potential leaks from underground fuel storage tanks threaten groundwater, and improperly disposed of used motor oil ends up in waterways. Noise Pollution Noise from car traffic, and loud car stereos and alarms, has become so ubiquitous that we barely notice it anymore -- but it’’s taking its toll. Recent census data indicates that 1 in 8 American households suffer from bothersome noise from the street or traffic. Problems related to noise include hearing loss, stress, high blood pressure, sleep loss, distraction, and lost productivity, and a general reduction in the quality of life and opportunities for tranquility. Solid Waste Over 10 million automobiles are scrapped every year, creating approximately seven billion pounds of unrecycled scrap and waste every year. Approximately 800 million tires are stockpiled in dumps around the country, creating a serious fire hazard and an ongoing environmental hazard. Every stockpiled tire sheds rubber each year, spewing minute grains of rubber into the atmosphere and back down into the water supply and human lungs. Wildlife The Humane Society estimates that around a million animals die on U. S. roads every day. Agriculture Air and water pollution from vehicles compromises the growth, reproduction and over all health of plants, which are susceptible to disease, pests, and environmental stress. It reduces agricultural yields for many economically important crops, such as soybean, wheat, and cotton. The Built-up Environment During the last century, an area roughly equal to all the arable land in Ohio, Indiana and Pennsylvania was paved in the United States -- requiting maintenance costs of over $ 200 million a day and trapping us in large, sprawling and undesirable concrete jungles. Approximately one-third of an average city’’s land is devoted to roads and other car-related elements. Interstate highways cut through and divide countless neighborhoods, taking homes and destroying businesses. We add more and more roads, encouraging wider use of private cars and ever-increasing traffic congestion. Out of the seven pollutants mentioned in the first half of the article, hybrid cars produce fewer pollutants in at least five cases.