Table 4

Indoor air pollution from biofuel combustion in developing countries

Location and year	Description	n	Particulate concentration (μg/m³)	Reference
Kitchen area concentration
Papua New Guinea
1968	Overnight at floor level	9	200–4900	Cleary & Blackburn101
1974	Overnight at sitting level	6	200–9000	Anderson102
Kenya
1971–72	Overnight - highlands	5	2700–7900	Hofmann & Wynder103
	- lowlands	3	300–1500	Clifford104
1988	24 hours	64	1200–1900 (RSP)	Boleijet al 105
India
1982	15 min cooking - wood	22	15 800	Aggarwalet al 106
	- dung	32	18 300	Patel et al 107
	- charcoal	10	5500
1988	Cooking (0.7 m to ceiling)	390	4000–21 000	Menon108
Nepal
1986	Cooking - wood (geometric mean)	17	4700	Davidson et al 109
China
1987	All day - wood	?	2600 (RSP)	Mumford et al 110
The Gambia
1988	24 hours	36	1000–2500 (RSP)	Boleij et al 105

Exposures during cooking (2–5 hours per day)
India
1983	4 villages	65	6800	Smith et al 111
1987	8 villages	165	3700	Ramakrishna et al 66
1987	2 villages	44	3600	Ramakrishna112
1988	5 villages	129	4700	Menon108
1991	3 villages - winter	95	6800	Saksenaet al 113
	- summer		5400
	- monsoon		4800
Nepal
1986	2 villages^4-a	49	2000	Reid et al 114
1990	1 village - before^4-b	20	8200 (RSP)	Pandeyet al 115
	- after	20	3000 (RSP)

↵4-a Approximately half “improved cookstoves”.
↵4-b Cooks' exposures measure before and after introduction of improved stoves.
The studies are not completely comparable because of different measurement protocols and equipment but, nevertheless, are fairly consistent. Area concentrations are measured with stationary instruments placed indoors at breathing height. Exposure rates were measured with instruments worn by the cook during food preparation. For comparisons, the US 24-hour standard, not to be exceeded more than once per year, has been 260 μg/m3 and the Japanese one-hour standard is 200 μg/m³. Some of the studies listed here also measured other pollutants, including carbon monoxide and benzo(a)pyrene, which were sometimes found in concentrations well above those found in public settings in developed countries, as well as nitrogen and sulfur oxides and formaldehyde, which were found in concentrations roughly equal to the high end of those measured in indoor developed country conditions.
Modified from Pandey et al.49