Ключевые слова: air, backgrounds, building, business, carbon, chemical, chemistry, chimney, city, cloud, coal, construction, dawn, energy, environment, factory, fuel, fumes, gas, generation, global, industry, natural, nature, physical, pipe, plant, pollution, power, silhouette, sky, smog, smoke, smoking, stack, station, steam, structure, substance, sun, sunrise, sunset, technology, temperature, tower, tube, up, warming, water, winter,