Ключевые слова: air, atmosphere, background, black, bubble, carbon, carbonic, chemistry, cloud, co2, combustion, concept, contamination, damage, danger, dioxide, discussion, eco, ecological, ecology, emission, energy, environment, environmental, exhaust, flat, formula, gas, global, greenhouse, hand, icon, industry, issue, label, pollutant, pollute, pollution, reduce, reduction, sign, smog, smoke, stamp, symbol, text, toxic, warming, warning,