How can I check my lungs at home?

At home, you may check your lungs functioning with an instrument named "Peak Flow meter". It is a small hand held device, when you blow air into it, it calculates the lung capacity and expansion. Spirometer is another instrument which helps in similar way in lung assessment and additionally it also has therapeutic usage. You may check oxygenation level by "Pulse Oximeter" which gives indirect clue on lung damage but keep in mind there are other medical conditions which may affect pulse oximeter readings.