Ключевые слова: air, atmosphere, background, black, blue, chemical, chimney, city, climate, coal, damage, danger, diesel, dioxide, dirty, ecology, effect, emission, energy, engine, environment, environmental, exhaust, exhaust pipe, factory, fire, fuel, fume, gas, global, heating, industrial, industry, metal, nature, pipe, poison, pollute, pollution, power, sky, smog, smoke, steam, toxic, tube, urban, vertical, view, warming,