正如我们从事实中了解的那样,城市越大,空气质量恶化越严重
As we know from, the bigger the city, the more serious the deterioration of air quality
我觉得这样译更恰当:
As we know from the facts that the bigger the city, the worse the air quality.
As we know from the facts as larger the city the more serious deterioration of air quality.