Ключевые слова: air, atmosphere, backgrounds, blue, building, business, chemical, chimney, cloud, color, day, dirty, ecology, electricity, energy, environment, environmental, equipment, factory, fog, fuel, fumes, gas, global, high, horizontal, industrial, industry, landscape, light, long, manufacturing, metal, nature, oil, outdoors, pipe, plant, pollution, power, refinery, sky, smog, smoke, stack, steam, technology, tower, toxic, warming,