Table 2.

Characteristics of the lifetime household fuel use for cooking and house heating purposes in the Golestan Cohort Study ($N=\mathrm{50,034}$).

Fuel and stove types	Purpose of usea
	Cooking [N (%)]	House heating [N (%)]
Gas	49,591 (99.1)	17,458 (34.8)
Using stoves without chimney	49,591 (100.0)	77 (0.4)
Using chimney-equipped stoves	—	17,360 (99.4)
Using both stove types	—	21 (0.1)
Kerosene	18,064 (36.1)	49,562 (99.0)
Using stoves without chimney	18,064 (100.0)	6,905 (13.9)
Using chimney-equipped stoves	—	13,531 (27.3)
Using both stove types	—	29,126 (58.7)
Biomass	43,840 (87.6)	44,790 (89.5)
Using stoves without chimney	43,840 (100.0)	6,489 (14.4)
Using chimney-equipped stoves	—	31,918 (71.2)
Using both stove types	—	6,383 (14.2)

Note: —, no data; N, number.

^aIn the Golestan region, natural gas, kerosene, and biomass were burned for cooking and house heating purposes. In this area, no cooking-stoves had chimney, although heating-stoves were available as chimney-equipped heating-stoves and heating-stoves without chimney.