Assessment of the Actual Toxicity of Engine Exhaust Gas Emissions from Euro 3 and Euro 6 Compliant Vehicles with the BAT-CELL Method Using In Vitro Tests

Abstract

Legal restrictions on vehicle engine exhaust gas emission control do not always go hand in hand with an actual reduction in the emissions of toxins into the atmosphere. Moreover, the methods currently used to measure exhaust gas emissions do not give unambiguous results on the impact of the tested gases on living organisms. The method used to assess the actual toxicity of gases, BAT-CELL Bio-Ambient-Tests using in vitro tests, takes into account synergistic interactions of individual components of a mixture of gases without the need to know its qualitative and quantitative composition and allows for determination of the actual toxicity of the gas composition. Using the BAT-CELL method, exhaust gases from passenger vehicles equipped with spark-ignition engines complying with the Euro 3 and Euro 6 emission standards were tested. The results of toxicological tests were correlated with the results of chromatographic analysis. It was shown that diverse qualitative composition of the mixture of hydrocarbons determining the exhaust gases toxicity may decrease the percentage value of cell survival. Additionally, it was proven that the average survival of cells after exposure to exhaust gases from tested vehicles meeting the more restrictive Euro 6 standard was lower than for vehicles meeting the Euro 3 standard thus indicating the higher toxicity of exhaust gases from newer vehicles.

The Actual Toxicity of Engine Exhaust Gases Emitted from Vehicles: The Development and Perspectives of Biological and Chemical Measurement Methods

“…It is currently an original solution for the methodology of this type of research. Studies have shown that Euro 6 vehicles have 4% higher cell survival rate than Euro 3 vehicles (Figure ). Therefore, selecting the appropriate time of cell exposure to toxins is very important in the measurement procedure and should be adjusted depending on the use of physicochemical barriers that hinder direct contact of cells with the toxic gas mixture.…”

“…54 Another problem is the fact that the standards do not limit the emissions of some of the very harmful groups of compounds that determine the toxicity of engine exhaust gases. 55 The emission standards in their present form certainly raise some questions. At the same time, there are alternative solutions that can be used to determine the actual toxicity of engine exhaust gases in a simple and undisputed way, reflecting the actual impact of exhaust gases on living organisms (Figure 3).…”

“…The more diverse the qualitative and quantitative composition of PAHs and VOCs, the more cells degenerated. 55 It is worth mentioning that microscopic methods are an important tool in the biological evaluation of cells. Confocal microscopy is used to assess cell morphology after exposure to gas mixtures, 60 and transmission electron microscopy is used to assess the morphology and size of solid particles.…”

“…It is a known fact that the current tests do not cover the full range of frequent driving conditions that can result in increased emissions, such as short urban distances of less than 16 km, ambient temperatures below −7 °C or above 35 °C, or altitudes above 1300 m. Difficulties in emission control also result from the regulation loopholes, which create opportunities to optimize emission control systems in vehicles in order to improve the type-approval test results . Another problem is the fact that the standards do not limit the emissions of some of the very harmful groups of compounds that determine the toxicity of engine exhaust gases …”

“…Figure 4. Correlations between the values of percentage cell survival and the number and cumulative concentration of compounds determined in the PAH group 55. …”