Ключевые слова: air, air pollution, airplane, atmosphere, blue, blue sky, burning, carbon, chemical, chemistry, chimney, climate change, clouds, co2, dioxide, dirty, ecological, ecology, electricity, emission, energy, environment, environmental, exhaust, factory, flight, fumes, gas, gasoline, global, global warming, greenhouse, industrial, industry, ozone, pipe, pipeline, plane, pollution, production, sky, smog, smoke, stack, steam, toxic, trail, warming, weather, white,