为什么城市的空气质量越来越差？温室效应究竟是指什么

今天的这段对话，在讨论环境污染，
 
为什么城市的空气质量越来越差？温室效应究竟是指什么
 
来听今天的讲解:
 
A:  the air quality in this city is horrendous! The pollution levels were so high that we weren't supposed to go outside with a face mask again!
 
这个城市的空气质量实在是太差了!污染指数那么高,以至于我们都已不再希望于外出时戴防毒面具保护自己了.
 
B:  exhaust fumes from vehicles cause a great deal of damage to the environment.
 
汽车排放的尾气严重污染了环境.
 
A:  on top of that, there are a few large chemical factories in the suburbs, which are contributing to the high pollution levels in the water and the air in this city.
 
最要命的是,郊区还有好几家大型化工厂,这些工厂是这个城市空气和水污染的罪魁祸首.
 
B:  as much as I love this city, I think I'm going to have to find a greener city to live in. Living in a polluted city like this just can't be good for my health.
 
我热爱这个城市但是我也想找一个更加环保的城市居住.住在污染这么严重的城市里对我的健康可是不好的.
 
A:  I know what you mean. However, there are so few places left that have not been affected by global warming. If it's not the pollution, then it's the natural disasters, deforestation, or the greenhouse effect.
 
我明白你的意思.不过现在已经很少有城市不受全球变暖的影响了.不是有污染,就是有自然灾害,或者是森林毁坏和温室效应.
 
B:  what is the greenhosue effct exactly?
 
温室效应究竟是指什么?
 
A:  it's the gradual rise in the earth's temperature.
 
是指地球温度逐渐上升.
 
B:  I see, so it's similar to global warming?
 
我明白了.是不是跟全球变暖很相似?
 
A:  they're related to one another, yes.
 
没错,他们是彼此联系的.
 
B:  I heard that some people in England are pleased with the fact that the climate is becoming warmer because it's making their towns a more pleasant place to live.
 
我听说英国的一些人对气候变暖感到高兴，因为这使他们的城镇成为一个更宜人的生活场所。
 
A:  people joke about the benefits of the increase in temperature, but it's not all good news. They've been experiencing a lot of deadly storms there as well.
 
有时候人们会拿气温升高的好处开开玩笑,不过这毕竟不是好事.他们已经经历过因此而造成的暴风雨雪天气了.
 
B:  people always seem to make jokes as a way to deal with unfortunate situations.
 
人们总是会调侃这个,就像他们面对不幸境遇的时候一样.
 
A:  I think if everyone pitches in, the world will be a better place.
 
我觉得如果人人都能同心协力,这个世界将会更美好.