I wonder how the atmosphere on the example exo-planet (RS 0-B-3894743-1646-33-B-7338743-B02 3) is breathable at only .229 atm. It seems like at 0.21 atm a 100% pure O2 atmosphere with no inert balance gas should be fine for people, but at about 0.35 atm (around 8000m elevation on Earth) life is impossible. Pulmonary and cerebral edema lead to death. You could possibly survive down to .12 atm but need a pure oxygen supply. At 0.0618 atm water boils at human body temp. With a higher atm more oxygen is forced into the lungs there-by requiring less percentage of oxygen in the air. Oxygen toxicity must be considered for exposure concentrations greater than 50 percent at 1 atm. Pure oxygen can be breathed for limited periods of time: up to 3 hours at 1 atm and 1 hour at 3 atm of pressure. Adverse effects from breathing pure oxygen at sea-level pressure can be felt in 4 to 24 hours. Plus that's pretty low gravity, that surely affects how well humans breath too, they would lose lower body strength and their lungs would expand due to the lack of gravity. I guess I can let that example planet slide for now.
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Here's a half dozen of planets that come fairly close but fall short of breathable for various reasons
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List of other "Close, but don't try to light that cigar just yet" candidates:
HIP 43077 4 : .198atm 18% O2, 1.6% CO2, .040% SO2, .002% H2S, .283% CH4 Temp 10F
Lambda Aurigae 4 : .305atm 28% O2, 1.7% CO2, .314% SO2, .0005% H2S, .011% CH4 Temp 30F
RS 5408-0-7-913985-114 3 : 1.93atm 16% O2, 8.3% CO2, .482% SO2, 0.00% H2S, 0.00% CH4 Temp 173F
RS 6637-5538-8-20178-87 B3 : .891atm 15% O2, 7.3% CO2, .095% SO2, .003% H2S, .001% CH4 Temp 171F
RSC 5510-4444-3-112-5 3 : .507atm 14% O2, 8.0% CO2, 1.91% SO2, .003% H2S, .009% CH4 Temp 193F
RS 8475-7-6-21783-242 3 : .989atm 49% O2, 7.6% CO2, .166% SO2, .183% H2S, .911% CH4 Temp 121F
RS 1169-2-4-2798-255 4 : .596atm 50% O2, 7.7% CO2, .124% SO2, .024% H2S, .947% CH4 Temp 12F
RS 6637-5538-8-20179-76 B3 : .886atm 64% O2, 8.5% CO2, .996% SO2, .108% H2S, .078% CH4 Temp 123F
RS 6552-173-5-17103-55 7 1.12atm 78% O2, 8.8% CO2, .145% SO2, .004% H2S, 1.47% CH4 54F
HIP 11389 4 .984atm 81% O2, 6.6% CO2, 1.49% SO2, .465% H2S, 6.28% CH4 30F
RS 8475-6-5-7001-283 B3 .860atm 51% O2, 11.4% CO2, .158% SO2, .009% H2S, .132% CH4 168F
RS 6637-5538-6-315-224 4 1.04atm 30% O2, 13.4% CO2, .141% SO2, .007% H2S, .071% CH4 57F
RSC 6637-1720-4-1797-28 5 1.39atm 114% O2, 20.0% CO2, 2.8% SO2, .187% H2S, 1.44% CH4 6F
RSC 5563-545-3-31-3 8 .968atm 71% O2, 25.1% CO2, .056% SO2, .073% H2S, .260% CH4 41F
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I have a feeling the algorithms used by SE to generate atmospheres will not allow numbers to be in breathable range for humans.