Which of the following refers to articles or substances that can pose significant risks to health or safety when transported by air?

The term that refers to articles or substances posing significant risks to health or safety during air transport is Dangerous Goods. This classification includes a wide range of materials that can be explosive, flammable, corrosive, toxic, or otherwise hazardous to human health or the environment. Regulations are in place to govern the handling, packaging, and transportation of these goods to ensure safety in aviation operations. This concept is essential in logistics and supply chain management, particularly in the context of air freight, where the risks are heightened due to the nature of air travel and the environments to which these goods may be subjected.

The other terms do not specifically encompass the broad array of items that are classified under Dangerous Goods. Pollutants generally refer to substances that contaminate the environment but do not necessarily imply air transport risks. Unwanted Substances could refer to a variety of materials that might not be hazardous. Toxics, while they describe harmful substances, do not cover the full spectrum of dangerous goods which can include non-toxic items that are still hazardous when transported. Thus, Dangerous Goods is the most comprehensive and accurate descriptor in this context.