How a California DUI breath test sample should estimate a person's Blood Alcohol Content

You were just arrested for a California DUI.  A California DUI Attorney asks you what your Blood Alcohol Concentration (BAC) level was. The understanding of the California DUI breath test is for a driver to blow into a breath machine.   The machine is supposed to give us some idea of how much alcohol the driver has been drinking.Here's how inhaled air becomes presented California DUI evidence which may or may not tell us exactly how much a California driver has been drinking.When a person inhales, air from the room goes into their lungs.The air goes into these tiny air sacks.These sacks are lined with capillaries that  carry blood to the sacks. Inside these sacks is where gasses are exchanged from the air to the blood, and from the blood to the air.  Among other things, there's a natural O2 and CO2 exchange.Alcohol is a volatile chemical. That means when there is liquid alcohol present, a portion of that alcohol will escape as a gas.This escaping alcohol gas gets into the air inside these tiny air sacks. The more alcohol that jumps into the air inside these tiny sacks, the more alcohol the driver will blow into the machine when they exhale.Of course, how much someone has been drinking has an effect on how much alcohol will go into the air.There are other factors besides how much someone has been drinking that will cause this amount of alcohol to change:In fact, if 1000 people of the exact same height, weight, and sex, if they all had the exact same amount to drink, and if they all blew into a breath machine, you could get 1000 different numerical BACs.Notably, there could be over 300% difference in the lowest and highest breath alcohol result you would get.All of those differences in those equal drinkers would be due to natural or biological differences in those individuals. For example, you would have:  (a) some people who could blow .05%, and (b) some could blow .15%.(a) .05 is a lawful alcohol concentration, while (b) 15 is almost twice the legal limit. In conclusion, these same people - who could be as low as .05 or as high as .15 - would have had the same amount of alcohol to drink.  So similar people could drink the same amount of alcohol yet have BAC's .10 different.