Introduction and objective: This study evaluated the impact of day-to-day air pollutants, such as particulate matter PM_2.5, PM₁₀, nitrogen dioxide (NO₂), and ozone (O₃) on the development on asthma and allergy in preschool children. Materials and methods: A total of 284 5-year-old children participated in the study. The questionnaires were completed by the caregivers. For each child, the visit involved skin prick testing and the distribution of backpacks containing GilAir Plus Basic personal aspirators for 24-hour measurement of PM_2.5 and PM₁₀. The dust samples were analysed in the laboratory. Air pollutants in the place of residence have been assessed for 5 years using the CALMET/CALPUFF modelling system. Results: Significantly higher levels of PM_2.5 (as measured by personal aspirators), 2015 PM_2.5 [μg/m³] and 2015 PM₁₀ [μg/m³] were observed in the allergy group in comparison to the no-allergy group. 2018 and 2019 ozone levels differentiated the analysed groups. In multivariate analysis, passive smoking was associated with a 3-fold increase in the risk of allergy (odds ratio – OR = 2.76, 95% confidence interval – 95% CI [1.21;6.53], p = 0.017). Among the analysed pollutants, 2017 PM₁₀ [μg/m³] increased the odds of allergy with the highest strength. An increase in its concentration by 1 μg/m³ resulted in 14% higher odds of allergy (OR = 1.14, 95% CI [1.02;1.28], p = 0.021). Among the assessed pollutants, 2017 ozone increased the odds of asthma, with an increase in its concentration by 1 unit resulting in 41% higher odds (OR = 1.41, 95% CI [1.02;2.04], p = 0.049). Conclusions: Exposure to PM_2.5, PM₁₀ and ozone seem to increase the overall risk of allergy and asthma. Passive smoking showed the strongest correlation with an increase in the risk of allergy.