Low-pressure sodium (LPS) is a type of gas discharge lamp that produces light through the excitation of sodium vapor. These lamps are known for their distinctive yellow-orange glow and high energy efficiency. They are commonly used for street lighting and outdoor applications due to their long lifespan and low energy consumption. LPS lamps operate at low pressure, which allows them to emit a monochromatic light spectrum. This means they primarily produce light at a single wavelength, making them less effective for color rendering. Despite this limitation, their efficiency and durability make them a popular choice for urban lighting, contributing to reduced energy costs and lower environmental impact.