INTRODUCTION: Pollution and climate have an impact on pediatric respiratory diseases; few studies have assessed this in the Autonomous City of Buenos Aires. OBJECTIVE: To assess the impact of the interaction between air pollutants and climate on the Emergency Department visits for acute lower respiratory tract infection (ALRTI) in a children's hospital. METHODS: Ecological, time-series study with generalized additive models that included total visits and visits for ALRTI to the Emergency Department between 2012 and 2016. A series with 7-day moving averages for ALRTI visits was founded as a bias control measure. Predictors were daily levels of air pollutants (carbon monoxide, nitrous dioxide, particulate matter < 10 mu) and meteorological variables (temperature, humidity). Pollutants were measured at three monitoring stations. Temporal variables (day of the week, warm/cold semester) were controlled. RESULTS: There were 455 256 total visits; 17 298 accounted for visits for ALRTI. A correlation was established only between total visits and day of the week (Mondays and Saturdays, more visits; Thursdays, less visits). Less visits for ALRTI were recorded in the warm semester compared to the cold semester (relative risk = 0.23; 95 % confidence interval: 0.29-0.18; p < 0.001). One monitoring station did not show any correlation; the other two stations showed a weak correlation between carbon monoxide and particulate matter < 10 mu and visits for ALRTI. CONCLUSION: The season accurately accounts for the increased number of total visits and visits for ALRTI. Although there was a correlation between the level of certain pollutants and the number of visits, its impact was irrelevant.