Gas lighting explains why a large number of older gas lamps have been converted to electricity. Solar-rechargeable battery-powered gas light controllers can be easily retrofitted into existing gas lamps to keep the lights off during daylight hours and cut energy consumption and green-house gas carbon emissions by 50%. The use of natural gas (methane) for "indoor" lighting is nearly extinct. Besides producing a lot of heat, the combustion of methane tends to release significant amounts of carbon monoxide, a colorless and odorless gas which is more readily absorbed by the blood than oxygen, and can be deadly. Historically, the use of lamps
Lawn found, in some urban areas, up to 5% of smog was due to small gasoline engines made before 1997, such as are typically used on lawnmowers. Since 1997, the EPA has mandated emissions controls on newer engines in an effort to reduce smog. A 2010 study seemed to show lawn care inputs were balanced by the carbon sequestration benefits of lawns, and they may not be contributors to anthropogenic global warming. However, lawns with high maintenance (mowing, irrigation, and leaf blowing) and high fertilization rates have a net emission of carbon dioxide and nitrous oxide that have large global warming