Excessive use of plastic materials and poor management of plastic waste in modern times have created a growing problem in terms of environmental pollution and impact on living organisms that live in it, including humans. As part of recent scientific research, special emphasis is placed on microplastics, which are formed as a result of the fragmentation of plastic waste due to exposure to environmental conditions. This type of plastic represents a specific danger, since due to its size it can easily move through ecosystems, fit into food chains and accumulate in living organisms, on which it can have potentially harmful effects. In this work, the effect of polystyrene microparticles on the relative survival of human lung cell lines of healthy origin (WI-38) and tumor origin (H1299 and A549) was investigated. The dependence of survival on the size range of the microplastic particle, the concentration of the microplastic solution with which the cells were treated and the exposure time was observed. In order to establish the relative survival of the test cell cultures, the MTT test was performed. Program Desing Expert 7.1.5. was used to determine the experimental conditions under which the most harmful effect of microplastics on the test cell lines was achieved. In other words, those were the conditions under which relative cell survival was the lowest. For the WI-38 cell line, minimum survival was found at: 157.01 μm (PS particle size), 0.50 μg/mL (PS solution concentration) and 39.74 hours (exposure time), a significant process parameters were concentration and particle size. For H1299, the lowest survival was achieved at: 103.11 μm (PS particle size), 1.00 μg/mL (PS solution concentration) and 24 hours (exposure time), where the significant process parameters were concentration and exposure time. The A549 cell line had the lowest survival at: 200 μm (PS particle size), 2.00 μg/mL (PS solution concentration) and 51.17 hours (exposure time), while the only significant process parameter was time. According to the obtained results, it was concluded that the harmful effect of PS microplastics in terms of reducing relative survival exists. Also, depending on the test cell culture type, the decrease in survival depends on the size of the PS particle, the concentration of the solution and the exposure time.