The physical form of a city is one of the factors that shape the concentrations of air pollutants measured within it, yet the quantitative relationship between the intensity of development and measured concentrations remains poorly documented for Polish cities. This study determines the variation in mean annual concentrations of five air pollutants – benzo(a)pyrene (BaP), benzene (C6H6), NO2, PM10 and PM2.5 – in Kraków in 2018–2024, together with reported emissions, meteorological conditions, and the structure and intensity of the city’s development. Data comprised annual concentrations from the State Environmental Monitoring network, emissions reported to the National Centre for Emissions Management, and building data from the Database of Topographic Objects for 90,563 buildings in 18 districts. Relationships and trends were assessed by Spearman rank correlation with Benjamini–Hochberg correction; development was described by the pseudo-usable floor area, that is the building footprint area multiplied by the number of storeys. In 2024 all five pollutants were lower than in 2018, the largest decrease being for BaP (−83.8%). Significant monotonic decreases, and significant positive emission–concentration relationships, were obtained for BaP (ρ = −1.00 and 0.96) and PM10 (ρ = −0.96 and 0.93); none of the 15 meteorology–concentration pairs was significant. Low-rise and medium-rise buildings account for almost identical shares of the pseudo-usable floor area (43.68% and 43.51%), although building counts alone would indicate a decisive predominance of low-rise development (88.45%). Building intensity ranges from 10,019 m2/ha in Stare Miasto to 701 m2/ha in Nowa Huta. Building counts alone are therefore not a sound basis for assessing urban ventilation.