Effect of Implementing Electronic Toll Collection in Reducing Highway Particulate Matter Pollution

Area of Science:

• Environmental Science
• Public Health
• Transportation Engineering

Background:

• Highway vehicle emissions contribute to adverse health effects, particularly during traffic congestion.
• Electronic Toll Collection (ETC) policies aim to alleviate congestion and reduce air pollution.
• The impact of ETC on ultrafine particles (UFPs) and PM2.5 is not well understood.

Purpose of the Study:

• To investigate the effects of ETC implementation on traffic patterns and air quality, specifically UFP and PM2.5 concentrations.
• To quantify the reduction in UFP and PM2.5 levels and associated health risks after ETC deployment.

Main Methods:

• A case study was conducted at a highway site in Tainan, Taiwan.
• Measurements of UFP and PM2.5 concentrations were taken before and after ETC system implementation.
• Traffic volumes during peak hours were analyzed to assess traffic pattern changes.

Main Results:

• ETC implementation led to more homogeneous traffic volumes during peak periods.
• Significant reductions were observed in UFP number concentrations (4 × 10³ #/cm³) and PM2.5 mass concentrations (20.5 μg/m³).
• Excessive Lifetime Cancer Risk (ELCR) from combined PM2.5 and UFP exposure decreased by 49.3%.

Conclusions:

• ETC effectively alleviates traffic congestion and reduces harmful air pollutants like UFPs and PM2.5.
• Implementing ETC contributes to improved public health by lowering cancer risk for communities near highways.
• ETC is a viable policy for mitigating traffic-related environmental and health impacts.