Ключевые слова: acid rain, air, blue, cancer, chance, chemical, chemicals, chimney, climate, cloud, clouds, co2, contamination, damage, danger, destruction, dirty, dust, ecology, emission, energy, environment, environmental, factory, future, generate, get contaminated, global, greenhouse effect, industrial, industry, mill, ozone, paper, poison, pollute, polluting, pollution, sky, smog, smoke, smokestack, smokestacks, steam, thick, toxic, warming, waste,