On-road vehicular emission characterization from the road-tunnel measurements in India: Morphology, emission factors, and sources

Nagendra Raparthi; Harish C Phuleria

doi:10.1016/j.envres.2022.114295

On-road vehicular emission characterization from the road-tunnel measurements in India: Morphology, emission factors, and sources

Environ Res. 2022 Dec;215(Pt 2):114295. doi: 10.1016/j.envres.2022.114295. Epub 2022 Sep 17.

Authors

Nagendra Raparthi¹, Harish C Phuleria²

Affiliations

¹ Environmental Science and Engineering Department, Indian Institute of Technology Bombay, Mumbai, India.
² Environmental Science and Engineering Department, Indian Institute of Technology Bombay, Mumbai, India; Interdisciplinary Programme in Climate Studies, Indian Institute of Technology Bombay, Mumbai, India. Electronic address: phuleria@iitb.ac.in.

PMID: 36126689
DOI: 10.1016/j.envres.2022.114295

Abstract

In India, there is very limited data on vehicular emission characterization in real-world driving conditions and the contribution of non-exhaust vehicular emissions to ambient particulate matter (PM) is still unanswered. Furthermore, there are no real-world emission factors (EFs) for the PM constituents. Thus, this study aims to characterize the trace elements and metals, and black carbon (BC) in PM_2.5 and PM₁₀ from the light-duty vehicles (LDVs) and mixed vehicular fleet with significant contribution of heavy-duty vehicles (HDVs) through road-tunnel measurements. Real-world EFs were estimated for the measured PM chemical constituents. Further, source apportionment was carried out to find the plausible sources and their contribution to total PM_2.5 and PM₁₀ road traffic emissions. Air pollutant and traffic measurements were conducted at two roadway tunnels: Eastern Freeway tunnel (FT; only LDVs) and Kamshet-I tunnel (KT; 80% LDVs & 20% HDVs) in Mumbai, India covering both peak and off-peak traffic hours. Major elements (Al, Ca, Fe, K, Mg, and Na) constitute 90─93% of total measured elemental concentrations in both PM_2.5 and PM₁₀ road traffic emissions. Overall, the elemental concentrations were higher for the HDV-dominant fleet than the LDV-fleet for both PM_2.5 and PM₁₀. Similarly, BC was higher for the HDV-dominant fleet which is corroborated by the morphological analysis. The measured BC, trace elements and metals EFs in this study were higher than those reported than previous road tunnel studies with similar vehicle composition indicating the presence of high-emitting vehicles in this study. The dominant proportion of PM_2.5 road traffic emissions was from the tailpipe (52%) followed by brake wear (30%) and vehicular driven resuspended road dust (18%). Whilst, resuspended road dust (63%) was identified as the major source of PM₁₀ traffic emissions followed by vehicular exhaust (28%) and brake wear (9%). With the potential increase in the share of electric and hybrid vehicles in the vehicular fleet, the relative contribution of non-exhaust emissions to the airborne PM will be more significant. Hence, there is an imminent need to regulate non-exhaust vehicular emissions.

Keywords: Brake and tire wear; Emission factor; Exhaust; Non-exhaust; Resuspended road dust; Sources.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Air Pollutants* / analysis
Carbon / analysis
Dust / analysis
Environmental Monitoring
India
Metals / analysis
Particulate Matter / analysis
Soot / analysis
Trace Elements* / analysis
Vehicle Emissions / analysis

Substances

Air Pollutants
Dust
Metals
Particulate Matter
Soot
Trace Elements
Vehicle Emissions
Carbon