higher [e.g., ] ceilings. While these are general kitchen design trends, they have also influenced cabinetry. Kitchens today. Modern kitchen design has improved partly as a result of ergonomic research. Functionality is important; one research study had "anthropological scientists" observing homeowners "interact" with their kitchen cabinets. Kitchens are larger and have more cabinets; some kitchens may have as many as fifty drawers and cabinet doors. New features today include deep drawers for cookware, pull-out shelves to avoid excess bending, sponge trays on the front of sink cabinets, pullout hideaway garbage/recycling containers, pull-out spice cabinets, lazy susans in corner cabinets, vertical storage for cookie sheets, full-extension drawer slides, and drawers and doors with so-called soft-close/positive-close mechanisms enabling drawers to shut quietly, or which shut fully after being pushed only partially. As housing stocks get older, many homeowners face problems with visually unappealing older kitchen cabinets; in such situations, there is a choice to buy new (most expensive), reface existing (less expensive), or to strip and refinish existing (least expensive if done by the homeowner) cabinets. By 2009, there was more emphasis on cabinets designed with environmental factors in mind. So-called "green cabinets" were becoming more popular. As homes in Western countries became more airtight to save on heating and cooling costs, air quality has sometimes suffered as gases which are released from resins as they cure. Resins, organic materials which convert from liquid to solid form, are used to manufacture engineered wood (e.g., particleboard) frequently used to build kitchen cabinet carcases can be a factor. According to a recent report: Considering that North Americans spend a large proportion of their lives indoors, it’s clear why this is a key issue in designing healthy spaces. Additionally, air quality is not a stand-alone problem; rather, every other component of the home can affect air quality. Air quality can be compromised by off-gassing from cabinetry, countertops, flooring, wall coverings or fabrics; by cooking by-products released into the air, and by mold caused by excess moisture or poor ventilation. Universal design Some designers have begun to build houses and cabinetry to address the needs of users throughout the human life cycle and among all user capabilities, under a concept called universal design. The United States requires universal design for federally-funded housing, under the Americans with Disabilities Act of 1990. Universal design features include easily manipulated handles, low switches, and numerous other innovations. Cabinet wood choices