Placing grilles, grates or mats at all major entrances is an example of permanent entryway systems used to reduce dust, dirt and contaminants brought into a facility. Permanent entryway systems are designed to capture dirt and particulates from people’s shoes and prevent them from entering the indoor environment. This improves the indoor air quality and reduces the need for cleaning and maintenance. The LEED Green Associate Candidate Handbook states that one of the strategies for achieving indoor environmental quality is to “use permanent entryway systems (grilles, grates, mats) to reduce particulate matter being brought into buildings at regular entryways” [1, p. 16]. References: LEED Green Associate Candidate Handbook, [Indoor Environmental Quality | U.S. Green Building Council]