Air pollution, encompassing a range of substances like particulate matter, ozone, sulfur dioxide, and nitrogen oxides, poses significant threats to public health and the environment. A common crossword clue, often referencing legislation designed to mitigate these threats, points to specific pollutants regulated by landmark environmental law.
Controlling these substances is crucial for protecting respiratory health, reducing the impacts of acid rain, and mitigating visibility impairment. The historical context involves evolving scientific understanding of the detrimental effects of air pollution, leading to legislative action and technological advancements aimed at reducing emissions from various sources, including industrial facilities and vehicles. These efforts have demonstrably improved air quality in many regions, highlighting the importance of continued regulation and innovation.