Ключевые слова: air, alternative, atmosphere, blue, carbon, change, chemical, chemicals, chemistry, clean, climate, contamination, dioxide, earth, eco, ecological, ecology, ecosystem, emission, emissions, energy, environment, environmental, gas, gases, global, globe, green, greenhouse, harmful, industrial, industries, industry, naturally, photosynthesis, planet, pollutant, pollutants, pollute, pollution, reduce, reducing, reduction, sign, source, sources, sustainability, sustainable, warming, warning,