QUESTIONNAIRE STUDY OF THE EFFECT OF METE OROLOGICAL CONDITION, PARTICULARLY FOG, ON THE SYMPTOMATOLOGY OF ASTHMATIC-PATIENTS

The role of fog in the symptomatology in asthmatic subjects has been a ssessed by a questionnaire concerning respiratory complaints linked to meteorological conditions and to non-specific irritant factors. In a population of 121 asthmatics (59 men and 62 women) 74.4% complained th at fog was a factor aggravating their symptoms while only 3% of a grou p of 30 non-asthmatic subjects expressed discomfort during episodes of fog. The chemical analysis of fog during 32 episodes of local fog (pH , chloride, nitrate, sulphate, sodium, ammonia, potassium, magnesium, calcium) has shown a greater concentration of pollutants and greater a cidity in the smaller particles (2-6 mu m) which are able to penetrate the bronchial tree. This acidity could explain the role of fog in res piratory physiology. Certain authors have suggested that the aggravati on of respiratory symptoms observed during peaks of pollution could be induced by aerosols containing sulphuric acid while others have descr ibed effects on respiratory function at the rime of exposure to acid a erosols in asthmatic subjects but the results of the different studies have not all been concordant. Putting aside the role of the susceptib le individual, other factors may intervene at the time inhalation of p ollutants, notably the ambient humidity, the neutralising effect of en dogenous ammonia and the synergystic effect between acid aerosols and atmospheric pollutants.