A quadrat is a small, typically rectangular area set aside for ecological study.

A qualitative use assessment is a report that summarises the major uses of a pesticide including the amount of pesticide applied to a particular site and the percentage of the crop treated by pesticide.

Quality assurance or quality control is widely recognised in the environment industry, and refers to a system of procedures, checklists, audits, and corrective actions. These systems ensure that all research and development, environmental monitoring and sampling, and other technical and reporting activities satisfy quality requirements, comply with regulations, or meet environmental objectives.

Quarantine refers to a time-frame during which people, animals, luggage, substances or other materials that are suspected of carrying pests or diseases are confiscated and isolated, to prevent damage to other humans, animals or the natural environment. Australia has some of the strictest quarantine standards in the world due to its geographic isolation, and unique flora and fauna that require protection from overseas pests and diseases.

A quarry refers to an open-pit mine that is used to remove minerals and stone from the ground.  Quarries often require various abatement methods to address environmental problems such as noise, dust, and appearance.  Many quarries fill with water naturally after the quarry is closed, and become lakes or are made into landfills.