Comparative analysis of real-world vehicular emissions from BS-IV and BS-VI cars in India.

This study investigates real-world carbon dioxides (CO) and nitrogen oxides (NO) emissions from diesel (Bharat Stage-IV (BS-IV)) and petrol/gasoline (BS-IV and BS-VI) cars in Indian driving conditions using a portable emission measurement system (PEMS). The paired sample t-test revealed a significant difference ( < 0.05) in NO and CO emissions among the three types of cars, except for CO emissions ( > 0.05) between BS-IV petrol and BS-VI petrol cars. The highest NO emission rates were observed in all car types during acceleration (> 1 m/s) and deceleration (- 2 m/s). CO emission rates were also high during acceleration (> 1 m/s) for all car types. At low speeds (around 20 kmph), all car types had low emissions of CO and NO, with acceleration and deceleration rates ranging from - 0.5 to 0.5 m/s. BS-IV diesel cars emit significantly higher NO emissions compared to petrol cars, especially at vehicle-specific power (VSP) bin 0 (deceleration to idling mode) and during VSP bin 7 (acceleration mode). BS-IV diesel cars emit 228% and 530% higher NO emissions than BS-IV and BS-VI petrol cars at VSP bins 0 and 7, respectively. CO emissions from BS-VI petrol cars were 10% lower than those from BS-IV petrol cars across all VSP bins, indicating moderate reductions. Furthermore, diesel cars emit 140% less CO emissions than petrol cars across various VSP bins. The findings highlight the need for cleaner technologies and responsible driving practices to address vehicular emission concerns.