Related Experiment Video
Updated: Aug 24, 2026

A Novel Inhalation Mask System to Deliver High Concentrations of Nitric Oxide Gas in Spontaneously Breathing Subjects
Published on: May 4, 2021
Nitrogen dioxide is not associated with respiratory infection during the first year of life
Jordi Sunyer1, Carme Puig, Maties Torrent
1Unitat Recerca Respiratria i Ambietal, Institut Municipal Investigació Mèdica, Barcelona, Catalonia, Spain. jsunyer@imim.es
Background:
Nitrogen dioxide (NO(2)) has been related to respiratory infections in experimental studies but its role remains controversial in general population studies of children. We aim to assess the association between indoor NO(2) and lower respiratory tract infections (LRTI) during the first year of life in a multicentre prospective cohort study.
Methods:
Children (n = 1611) were recruited prior to birth for the Asthma Multicentre Infants Cohort Study (AMICS). Three concurrent cohorts (Ashford, Kent [UK]; Barcelona city, and Menorca Island [Spain]) followed the same research protocol. NO(2) was measured with passive diffusion tubes placed in the living room for 2 weeks when infants were approximately 3 months old. Doctor-diagnosed LRTI during the first year of life (as well as antibiotic use) were measured by questionnaire, and in Ashford validated by the examination of clinical records. In Barcelona, direct measurements using nasopharyngeal lavage and cultures within a continuous surveillance system were done.
Results:
The cumulative rates of LRTI (39% in Ashford, 28% in Barcelona, and 45% in Menorca) were unrelated to NO(2) levels (corresponding medians 6, 46, and 12 ppb, respectively) in all three centres (all odds ratios being around 1). Similarly, the rates of LRTI in Barcelona measured with the continuous record showed no association with NO(2) (all rate ratios being below 1). In addition, there was no association between rate of antibiotics courses per year per child (2.4 in Ashford, 1.7 in Barcelona, 0.9 in Menorca) and NO(2) levels.
Conclusions:
Indoor NO(2) at current levels does not seem to be involved in increasing respiratory infections by itself in infants, suggesting that the effects observed in studies on outdoor air are probably due to other copollutants.
Related Concept Videos
Respiratory Syncytial Virus Disease
Microbiota of the Respiratory Tract
Respiratory Assessment: Purpose and Indications
Objectives and Importance:
The primary goal of respiratory assessment is to evaluate patients at early risk of clinical deterioration. Since respiratory distress often precedes other signs of declining health, breathing patterns and sounds become a...
2° Amines to N-Nitrosamines: Reaction with NaNO2
Pneumonia I: Introduction
Pneumonia I: Introduction
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
