The act of crying impacts upon the observations. It causes increased blood flow to the face producing increased redness to the face and eyes. Increased blood flow to the respiratory tract brings more alcohol to the area and the production of nasal secretions and tears containing alcohol. These secretions and tears can contaminate the breath specimen resulting in erroneous elevation of the results of evidentiary breath testing due to the presence of the contamination with additional alcohol. (Garriott’s Medicolegal Aspects of Alcohol, 5th Edition, Edited by James C. Garriott, 2008, p. 123.)
While the subject is crying, there is also a tendency for the operator to hold the breath tube for a longer period of time after the subject has inhaled. This allows for more time for additional alcohol to pass from the respiratory tract and the secretions into the breath specimen before it is measured and extrapolated to arrive at the blood alcohol level. (Garriott’s Medicolegal Aspects of Alcohol, 5th Edition, Edited by James C. Garriott, 2008, p. 406.)
{Observations and Breath test}