Which of the following terms refers to pollutants that are generated directly from identifiable sources?

The term that refers to pollutants generated directly from identifiable sources is primary pollutants. These pollutants are emitted straight from the source and can include substances such as carbon monoxide from vehicle exhaust, sulfur dioxide from industrial processes, and particulate matter from construction sites. Since they originate directly from identifiable activities or sources, their effects can often be traced back to specific human activities or natural processes.

In contrast, secondary pollutants are not emitted directly; instead, they form in the atmosphere through chemical reactions involving primary pollutants. An example of a secondary pollutant is ozone, which is created when sunlight reacts with pollutants like volatile organic compounds and nitrogen oxides.

Fugitive emissions refer to unintentional releases of gases or vapors from pressurized equipment due to leaks or other unintended occurrences. Though they can be primary pollutants, they do not encompass all pollutants generated from identifiable sources. Lastly, greenhouse gases are a subset of pollutants that contribute to the greenhouse effect, and they include both primary and secondary pollutants, but they aren't specifically defined by their direct generation from identifiable sources. Thus, primary pollutants is the most accurate term for those that come straight from discernible origins.