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First integrated measurement of exhaust and non-exhaust particulate matter emissions of vehicles

The world's first attempt to measure particulate matter (PM) emissions generated by not only engine combustion but also the wearing down of brakes and tires is complete.

The Korea Institute of Machinery and Materials (KIMM), an institute under the jurisdiction of the Ministry of Science and ICT, announced that it has succeeded in an integrated experimental measurement of exhaust (engine combustion) and non-exhaust (tire and brake wear, road wear, and re-suspended road dust) emissions from the internal combustion engine and electric vehicles.

Until now, research on measuring the amount of non-exhaust PM emissions or identifying the phenomenon has rarely been conducted except for brake wear PM emissions. When estimating total PM emissions, superficial methods have used emission factors corresponding to each emission source listed in the national emission inventory.

It is the world's first attempt to measure the total PM emissions according to vehicle type and sources through integrated experimental measurements. The result of this study will be used to identify the cause of the non-exhaust emissions from internal combustion engines and electric vehicles and to develop guidelines for governmental policies to mitigate traffic-related PM emissions.

Seokhwan Lee and his research team in the Department of Mobility Power Research at the KIMM Institute of Carbon Neutral Energy Machinery conducted an integrated experiment and measurement of PM emissions according to the powertrain type for compact SUVs using an in-house developed tire wear simulator, brake wear simulator, and a mobile road dust measurement vehicle.

The results for gasoline, diesel, and electric vehicles were as follows. PM10 emissions were 42.3 mg/km for gasoline vehicles, 43.2 mg/km for diesel vehicles, and 47.7 mg/km for electric vehicles. PM2.5 emissions were 14.5 mg/km for gasoline vehicles, 14.1 mg/km for diesel vehicles, and 13.9 mg/km for electric vehicles.

In the case of the latest internal combustion engine vehicles, the current technological advancement of engine combustion and after-treatment devices have evolved considerably to reduce particulate matter emission. As a result, the share of non-exhaust PM in the total PM emissions has been increased to more than 90%.

According to Dr. Lee, "Electric vehicles do not emit toxic exhaust gases and greenhouse gases at all. Nevertheless, our results show that they do emit a significant amount of non-exhaust emissions." He added, "To improve urban air quality, the government should parallelly implement various policies to mitigate non-exhaust emissions, rather than only focusing uptake of the electric vehicles."

Provided by National Research Council of Science and Technology