Emerging challenges of air pollution and particulate matter in China, India, and Pakistan and mitigating solutions

The impacts of energy efficiency policies: meta-analysis

Vehicle emission inventory forms a critical element for the air pollution studies. The methodology for capturing intercity freight fleet operations is already available. However, urban freight activity and characteristics may be quite different from intercity freight operations. The present study thus aims to provide a generalised methodology to capture urban freight operations data relevant to emission estimates. Delhi has been selected as the case study city to illustrate the application of the proposed methodology. In order to quantify freight fleet emissions, relevant freight fleet characteristics such as age distribution, fuel distribution, fuel economy, and the number of in-use freight vehicles are established through on-field surveys. Further, special attention is paid to quantify the contribution of previously neglected external freight trips entering Delhi to the city’s air pollution. Comprehensive disaggregated analysis for external freight trips terminating in Delhi and transiting through Delhi is presented. 72-hour traffic count and a 24-hour origin and destination surveys are conducted at 17 entry locations of Delhi. Based on the captured characteristics, different emission scenarios are estimated for future policy intervention in the city. The developed methodology will serve as a means of generating emission relevant freight data for various urban areas. Integration of the urban and non-urban freight characteristics is expected to offer a robust and reliable national road freight transport emissions.

Assessment of freight vehicle characteristics and impact of future policy interventions on their emissions in Delhi

In India, there is uncertainty in vehicular emission estimation due to the lack of reliable emission factors (EFs) that represent the real-world driving conditions. In this study, real-world EFs of particulate (PM2.5, PM10, PM2.5-10, PNCs, and BC) and gaseous (CO, CO2, VOCs, and NO2) pollutants from on-road vehicles were developed from the roadway tunnel measurements. Air pollutants measurement campaign was carried out at the Eastern Freeway tunnel (South-bound) in Greater Mumbai in April 2019. Particulate and gaseous samplers were deployed at the entry and exit of the tunnel to measure the targeted air pollutants covering both peak and off-peak traffic hours. The average traffic in the tunnel was ~2450 h−1, dominated by Light-Duty Vehicles (LDVs) (~98%) with an average (±SD) vehicular speed of 59 (±5) km h−1. Almost ~93% of vehicles plying inside the tunnel were with ≤10 years of age and 87% of the fleet predominantly complied with Bharat Stage-IV (BSIV) emission standards. The measured average (±SD) fleet EFs for PM2.5, PM10, PM2.5-10, BC, NO2 and VOCs were 44.2 (±26.9), 118.1 (±28.5), 69.7 (±20.1), 147.0 (±31.5) and 92.9 (±20.7) mg veh−1 km−1, respectively. For CO and CO2, it was 1.6 (±0.3) and 132.4 (±25.0) g veh−1 km−1, and 2.1 (±0.5) ( × 1013 particles veh−1 km−1) for particle number concentrations. The coarse particle EF was 1.6 folds higher than the fine particle EF, signifying the importance of non-exhaust vehicular emission sources. Compared to laboratory-based EFs, the measured real-world EFs were 1.8, 4.8, and 2.2 folds higher for PM2.5, CO, and NO2, respectively. This is likely due to the presence of aged and poorly maintained vehicles in the real-world which were not taken into consideration by the lab-based studies. Capsule We developed hourly EFs of particulate and gaseous pollutants for on-road real-world vehicular fleet (having predominantly LDVs) from air pollution measurements and traffic characterization inside a motorway tunnel in Mumbai, India. Exhaust as well as non-exhaust EFs are developed and compared with the laboratory-based re-constructed EFs (which were 2–5 fold lower than real-world EFs).

Leeza Malik

Papers

Assessment of interstate freight vehicle characteristics and impact of future emission and fuel economy standards on their emissions in India