Table 1. The estimated cancer risks from indoor exposure to formaldehyde and benzene.

	City and country	Source of IURsa	Compound	Cancer risk (excess cases per 1 million population)
				Mean	SD	Median	95%
Our study	Beijing, China	OEHHAb	Formaldehyde	604	314	531	1,260
			Benzene	463	285	394	1,030
		U.S. EPA IRISc	Formaldehyde	1,340	771	1,160	2,880
			Benzene	131	96	107	304
Loh et al. [21] d	USA	OEHHA	Formaldehyde	100e
			Benzene	108e
		U.S. EPA IRIS	Formaldehyde	240e
			Benzene	30e
Sax et al. [20] d	New York City and Los Angeles, USA	U.S. EPA IRIS	Formaldehyde	205 (NYC), 258 (LA)e
			Benzene	25 (NYC), 34 (LA)e
Zhou et al. [36] f	Tianjing, China	U.S. EPA IRIS	Benzene	∼22e

^aIURs refers to Inhalation Unit Risk Values.

^bOEHHA: California Office of Environmental Health Hazard Assessment.

^cU.S. EPA IRIS: U.S. EPA Integrated Risk Information System.

^dThe cancer risk estimates from Loh et al. [21] and Sax et al. [20] represented the cancer risks associated with baseline exposure to formaldehyde and benzene in both indoor and outdoor microenvironments.

^eMedian cancer risk values are provided for Loh et al. [21], Sax et al. [20] and Zhou et al. [36].

^fThe cancer risk estimates from Zhou et al. [36] represented the cancer risks associated with exposure to benzene in both indoor and outdoor microenvironment.