© 2017 Elsevier B.V. 1,3-Butadiene is a carcinogenic compound that can be emitted to the atmosphere from several sources, such as the combustion of organic matter or traffic. However, petrochemical industry is one of the main origins of this compound. Several campaigns (2013-2017) were conducted in twelve Catalan urban areas to determine 1,3-butadiene concentrations in outdoor air, five of which were close to Tarragona petrochemical region. 1,3-Butadiene was dynamically sampled in multi-sorbent bed tubes (Carbotrap, Carbopack X and Carboxen 569) using portable pump equipment. The analysis was performed by automatic thermal desorption coupled with capillary gas chromatography/mass spectrometry detector. El Morell, Perafort and Puigdelfi´, located near petrochemical facilities, were the most impacted locations, with average concentrations up to 15±33, 33±41 and 27±39µgm-3, respectively. Maximum 24h concentrations of 125µgm-3 were observed in Puigdelfi´. However, 1,3-butadiene average and maximum concentrations in the Tarragona petrochemical region diminished significantly (p =0.05) in a drastic way (40-80%) since the first monitoring program in 2013. On the other hand, average concentrations in the rest of studied Catalan urban areas generally presented average values below 1µgm-3, ranging from 0.07-1.1µgm-3. Spain does have neither a monitoring strategy nor standard regulations related to 1,3-butadiene. Taking into account that relevant values can be found in locations near petrochemical facilities, a regulation should be implemented as soon as possible, at least in this specific areas.