Ключевые слова: air, air pollution, alternative energy, background, business, chemical, chemistry, chimney, city, cityscape, climate, cloud, coal, construction, dirty, district, eco, ecological, ecology, emission, energy, environment, environmental, exhaust, factory, gas, global, industrial, industry, manufacturing, nature, pipe, plant, pollution, power, power plant, production, smog, smoke, smokestack, station, steam, sunset, technology, town, toxic, tube, urban, warming, winter,