Bhashya
यस्मान्न विद्ध असुरै मुख्य , तस्मात् नैव एतेन सुरभि न दुर्गन्धि च विजानाति लोक , घ्राणेनैव तदुभय विजानाति , अतश्च पाप्मकार्यादर्शनात् अपहृतपाप्मा अपहृत विनाशित अपनीत पाप्मा यस्मात् सोऽयमपहृतपाप्मा हि एष , विशुद्ध इत्यर्थ ।यस्माच्च आत्मभरय कल्याणा-द्यासङ्गवत्त्वात् घ्राणादय — न तथा आत्मभरिर्मुख्य , किं तर्हि ? सर्वार्थ , कथमिति, उच्यते—तेन मुख्येन यद्श्नाति यत्पिबति लोक तेन अशितेन पीतेन च इतरान्क्षते एतमेव सन्तम् ' ऋषिमपि , तथा माध्यमा गृत्समदो विश्वामित्रो वामदेवोऽत्रि इत्यादीन् ऋषीनेव प्राणमापादयति श्रुति ,तथा तानपि ऋषीन् प्राणोपासकान् अङ्गिरोबृहस्पत्यायास्यान्प्राण करोत्यभेदविज्ञानाय— ' प्राणो ह पिता प्राणो माता 'इत्यादिवच्च ।तस्मात् ऋषि अङ्गिरा नाम, प्राण एव सन्,आत्मानमङ्गिरस प्राणमुद्गीथम् उपासाञ्चक्रे इत्येतत्, यत्यस्मात् स अङ्गाना प्राण सन् रस , तेनासौ अङ्गिरस ॥
In plain words
Since the primary breath was untouched by the demons, people do not perceive pleasant or foul odors through it, but through the nose alone. And because no trace of evil clings to it, it is truly 'apahatpapman'—one whose evil has been dispelled, washed away, and destroyed—completely pure. Unlike the individual senses which are bound by worldly attachments, the primary breath sustains all. Through it, whatever food and drink people consume, it nourishes the entire system... Thus the sage Angiras, who is none other than prana, meditated upon his own identity as the prana-udgitha, because as the vital essence of all the limbs, he is truly Angirasa.
Close to the Sanskrit
Because the principal breath was not pierced by demons, therefore the world does not perceive fragrance or foul odor through it; through the nose alone one perceives both. And because of the non-observation of sinful effects, he is free from evil — 'apahatpapma' meaning 'evil removed, destroyed, dispelled', for he is this pure one. And because the senses like smell have attachments and self-seeking, whereas the principal is not self-seeking in that way, but rather universal — how so? It is explained: through that principal one whatever food and drink the world consumes, with that consumed and drunk he supports the other breaths... therefore the sage named Angiras, being prana itself, meditated upon himself as Angirasa prana as the udgitha, because he being the essence of the limbs, therefore he is Angirasa.