Assessing the Effectiveness of Emission Reduction Policies in Mitigating Road Transport-Induced Air Pollution and GHG Emissions in a Non-Attainment City in India

This study investigates the impact of Road Transport Emission Reduction Policies (RTERPs) on air pollutant and greenhouse gas (GHG) emissions in Vijayawada, a non-attainment city in India. Utilising the Activity-Structure-Emission Factor (ASF) modeling technique, we developed an on-road transportation sector emission inventory for the base year 2021, encompassing both vehicle exhaust and non-exhaust emissions. The study found that vehicle exhaust emissions of PM₁₀, NO₂, CO, and HC in 2021 were 4.7 Gg, 5.6 Gg, 17.3 Gg, and 2.4 Gg, respectively.

The study evaluated the effectiveness of RTERPs under different scenarios for 2030. Alternative Scenario I (ALT-I-2030), incorporating national-level policies such as vehicle scrappage, cleaner fuels, and electric vehicle promotion, is projected to reduce pollutant emissions by 22-45%. For instance, PM₁₀ emissions are expected to decrease by 22%, while NO₂ emissions could see a reduction of up to 45%. ALT-II-2030, due to local-level strategies like low-emission zones in addition to national policies, demonstrates a more significant reduction in vehicle exhaust emissions, ranging from 42% to 68%. Under this scenario, PM₁₀ emissions are projected to decrease by 42%, and NO₂ emissions could potentially decline by 68%.

While ALT-II-2030 reduces CO₂ emissions from vehicle exhaust by 29% (from 550 Gg in 2021 to 390 Gg in 2030), the study highlights the potential for indirect CO₂ emissions from coal-based electricity generation to power the growing electric vehicle fleet, potentially offsetting the positive effects of RTERPs.

Non-exhaust emissions were also quantified, with resuspended road dust constituting the primary source, contributing approximately 94% of PM emissions (nearly 2.4 Gg) in 2021. Meanwhile, tyre, brake, and road wear contributed to 1%, 3%, and 2% respectively.  The spatial distribution of both vehicle exhaust and non-exhaust emissions exhibits significant heterogeneity, emphasising the need for localised control strategies in urbanising regions. This study underscores the importance of adopting balanced strategies that simultaneously address air quality concerns and promote sustainable transportation systems, aligning with Sustainable Development Goals 11.2 and 11.6.2.

Keywords: Road transport emissions, Emission inventory, Urban air quality, Scenario analysis, Exhaust and non-exhaust emissions