Autonomous vehicles opportunities for cities air quality.

Area of Science:

• Environmental Science
• Urban Planning
• Transportation Engineering

Background:

• Autonomous vehicles (AV) are expected to impact safety, energy, and emissions, yet their effect on urban air quality remains under-assessed.
• Previous studies have not comprehensively evaluated the air quality implications of AV integration into urban environments.

Purpose of the Study:

• To assess the impact of autonomous vehicles on urban air quality in a Portuguese city.
• To quantify changes in nitrogen oxides (NOx) and carbon dioxide (CO2) emissions and concentrations under different AV penetration scenarios.

Main Methods:

• A numerical modelling approach was employed, integrating road traffic, road transport emission, and Computational Fluid Dynamics (CFD) air quality models.
• Three scenarios were simulated: a baseline, a 30% autonomous vehicle penetration, and a 30% electric autonomous vehicle penetration scenario.

Main Results:

• The autonomous vehicle scenario led to a slight increase in NOx (+1.8%) and CO2 (+0.7%) emissions.
• The electric autonomous vehicle scenario resulted in approximately 30% emission reductions for both NOx and CO2.
• While the autonomous scenario showed mixed impacts on NOx concentrations, the electric autonomous scenario demonstrated a widespread reduction (average -4%).

Conclusions:

• Autonomous vehicles have the potential to improve urban air quality, particularly when they are electric.
• Further research is necessary to fully understand and optimize the air quality benefits of autonomous vehicle deployment.