Table 1. Physiological O₂ distribution in different organs/tissues^*.

Organ/tissue	%O2	pO2 (mmHg)	Concentration(μM)
Ambient air	21	160	206
Alveoli	14	104	134
Arterial blood	13	100	129
Kidney	4–9.5	30–73	39–94
Liver	4–7	30–54	39–69
Heart	2–6	15–46	19–59
Brain	3–5	23–39	29–50
Small intestine	2–9	15–69	19–89
Large intestine	0–6	0–46	0–59
Bone marrow	1.5–7	11–54	14–69

^*The O₂ levels in different organs are adjusted from references Burmester and Hankeln, 2014; Lecomte et al., 2005; Hatefi, 1985; Zaccara et al., 2019; Ball et al., 2014 and the partial pressure and concentration are calculated according to references Ortiz-Prado et al., 2019; Carreau et al., 2011; Jagannathan et al., 2016; Cigognini et al., 2016; Donovan et al., 2010; Mas-Bargues et al., 2019; Place et al., 2017.