The focus of this work was on the analysis of indoor air pollution. Indoor pollutants can come from typical household items such as furniture, carpets, cleaning products, cooking appliances and much more. Indoor air pollution can be much worse than outdoor air. While the concentrations of pollutants in outdoor air are regulated by laws and directives, there are no regulations for indoor air quality. The concentrations of the PM1 fraction (particles with an aerodynamic diameter of 1 μm or less) of particulate matter and the composition of polycyclic aromatic hydrocarbons (PAH) in the PM1 fraction were determined, and sampling was carried out in households in the Zagreb area and its surroundings. The Air Quality and Cleaner Air for Europe Directive (EU, 2008) does not set limit values for PM1, although they can be more dangerous to human health than PM2.5 and PM10 particles because their size makes them easier to disperse in the body. The highest mass concentration of PM1 particle fractions and the highest mass concentration of all PAHs were measured in the sample taken from a household in the Trstenik. In addition to Trstenik, elevated concentrations of PM1 and PAHs were also measured in households in Siget and Jarun. Significant spatial differences were observed, which indicates the necessity of further research that will take into account numerous factors such as the quality of the outdoor air, the physical characteristics of the household and the habits of the householders themselves. The dominant PAHs at almost all measurement sites are benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP), benzo[ghi]perylene (BghiP), and indeno[1,2,3-cd]pyrene (IP ). Based on the specific ratios of the individual PAHs, conclusions were drawn about possible sources of pollution (fossil fuels, coal combustion). A greater contribution was found from PAHs with a larger number of rings than from PAHs with 2 or 3 rings. The calculated mutagenic equivalent for the PAHs detected in the samples was 0.439 ng/m^3, while the carcinogenic equivalent was 0.313 ng/m^3. The results obtained confirm the suitability of BaP as a marker for the mutagenic and carcinogenic potential of various PAHs in the air. The values determined for the equivalents were low and therefore not indicative of poor indoor air quality in view of PAHs.