R&P
Rupprecht and Patashnik Co., Inc.

Radon
A colourless naturally occurring, radioactive, inert gas formed by radioactive decay of radium atoms in soil or rocks.

Receptor
1) In biochemistry: a specialised molecule in a cell that binds a specific chemical with high specificity and high affinity. 2) In exposure assessment: an organism that receives, may receive, or has received environmental exposure to a chemical.

Reconnaissance Visit
Pre-test visit to assess the suitability and safety of stack sampling facilities or location of air quality monitoring equipment.

Recycle/Reuse
Minimising waste generation by recovering and reprocessing usable products that might otherwise become waste (i.e. recycling of aluminium cans, paper, and bottles, etc.).

Recycling
Reusing materials and objects in original or changed forms rather than discarding them as wastes.

Reduction
The addition of hydrogen, removal of oxygen, or addition of electrons to an element or compound.

Remote Sensing
The capture of information about the Earth from a distant vantage point. The term is often associated with satellite imagery but also applies to aerial photography, airborne digital sensors, ground-based detectors, and other devices.

Representative Sample
A portion of material or water that is as nearly identical in content and consistency as possible to that in the larger body of material or water being sampled.

Ringlemann Chart
A series of shaded illustrations used to measure the opacity of air pollution emissions, ranging from light grey through black; used to set and enforce emissions standards.

Risk Management
The process of evaluating and selecting alternative regulatory and non-regulatory responses to risk. The selection process necessarily requires the consideration of legal, economic, and behavioural factors.

Rotary Kiln Incinerator
An incinerator with a rotating combustion chamber that keeps waste moving, thereby allowing it to vaporise for easier burning.

Route of Exposure
The avenue by which a chemical comes into contact with an organism (e.g., inhalation, ingestion, dermal contact, and injection.)

Run-Off
That part of precipitation, snowmelt, or irrigation water that runs off the land into streams or other surface-water. It can carry pollutants from the air and land into receiving waters.