common to outdoor ranges. Several studies of outdoor ranges have shown that prolonged exposure to lead and noise can cause health problems, particularly among employees and instructors. Due to their larger area and more "open air" nature, outdoor ranges need less cleaning and maintenance than indoor ranges. However, despite the natural ventilation of outdoor firing ranges, some outdoor ranges have ballistic baffles overhead, and concrete walls and structures on the sides that can cause the air to stagnate and lead to increase exposure to lead and noise. Consequently, operators of outdoor ranges might consider adding sound transmission barriers, absorptive materials, and natural vegetation to lessen noise emission. Fans pointing downrange can provide air movement away from shooters to lessen lead exposure. Air rifle Outdoor air rifle ranges can have a fixed distance such as or or be an area for the practice of the sport of field target shooting, where reset metal targets are placed in natural surroundings at various distances and elevations, with a pellet trap behind the target. Small-bore rifle Small-bore (.22 Long Rifle caliber) rifle ranges are typically to accommodate the Olympic 50 m Rifle event, but they can extend to . These ranges are found around the world as part of various cadet shooting programs, sometimes reduced to , or in American parlance "the thousand-inch range". Often called "miniature rifle ranges", they featured as training establishments for initial military marksmanship training using lower-cost ammunition imparting less recoil or for entertainment carnival games or, if built to a high specification, are used for zeroing-in full-bore rifles using specially designed "ladder" targets. Full-bore rifle Target shooting range for larger-caliber centerfire rifles are no shorter than , except in the case of “Zero” ranges used for setting or checking the open (iron) or aperture (peep) sights of the rifle and telescopic sight “Zero”. Military ranges are typically at least to safely accommodate the range of most rifles. Public ranges can be as long as and typically accommodate hunters and sportsman participating in sports such as 300 m Standard Rifle, metallic silhouette or benchrest shooting. Shotgun Specialist ranges cater for various clay pigeon shooting events and require special layouts and equipment. Archery ranges Oftentimes the same range is made available to both bow and gun shooters. However, there are many ranges that have been made available exclusively for archers, and thousands of them can be found in the USA. The