Introduction. Peak Expiratory Flow Rate (PEFR) was first described by Hadorn as a measure of the lung function. The definition of PEFR established by the European Respiratory Society defines it as the maximal flow achieved during the phase of expiration, delivered with maximal force and starting from the maximal lung inflation level.

Aim. The authors of this study attempted at evaluating the variations of PEFR, taking into consideration the effects of one’s age, height Body Mass Index (BMI), Body Surface Area (BSA), seasons of the year and air pollution. Healthy adults living in urban areas were subjects of the study.

Material and methods . The study group consisted of some 179 healthy subjects, 102 women and 77 men, aged 18 to 66. Every patient’s medical history, including epidemiological, demographic data, as well as the information about the occurrence and symptoms of lung diseases, was taken from every patient. Only healthy subjects were selected for further analysis. Participants performed spirometry testing. Physical parameters were measured. Appropriate pollution data was obtained.

Results. The study group consisted of 179 patients (102 women and 77 men). There is a negative correlation between PEFR and age and a positive one between PEFR and height, as well as Body Surface Area and BMI (regarded as a quantitative, but not as a qualitative trait). There is a significant correlation between PEFR and PEFR adjusted by age, height and weight with seasons of the year. There is a statistically significant negative impact of NO2, SO2 and O3 24 h mean and hourly NO2 concentration on PEFR.

Conclusions. Peak Expiratory Flow Rate changes are also present in a healthy adult population. Prevalence of obesity is an important factor of the examined population.