Objective Some studies have compared the occurrence of croup with air pollution. Results have so far remained contradictory. Motor vehicles represent the principal source of air pollution in the city of Vinnytsya, Ukraine. The objective of this study was to determine the relation of traffic load to traffic-dependent pollutants and croup.

Methods Among a population of 8.067 children in residence near areas of high traffic density (>1.500 motor vehicles/ hour) and 2.473 children in residence near areas of low traffic density (<300 motor vehicles/ hour) cases of croup were registered by physicians during a 4 years period in 2000–03. Air pollution by sulfur dioxide (SO2), nitrogen dioxide (NO2), particulate matter, carbon monoxide (CO) were locally measured.

Results Areas with high traffic load are characterised by higher concentration of traffic-dependent pollutants and higher annual incidence of croup (Table).

Table. Traffic load, traffic-dependent pollutants and annual incidence of croup in children (Vinnytsya, Ukraine, 2000–2003)

Conclusions Croup in children is related to traffic load and traffic-dependent pollutants (SO2, NO2, particulate matter, CO).