Estimating the contribution of vehicle composition on air pollution – A case study in Chittagong-Rangamati Highway

• Main Authors: Tabassum, Nafisa, Khan, A. F. S. Ahad Rahman, Arefin, Aohona
• Format: Conference Proceeding
• Language: English
• Subjects: Air pollution; Air quality; Automobiles; Carbon monoxide; Composition; Dependent variables; Emissions control; Highways; Independent variables; Mathematical analysis; Mathematical functions; Nitrogen oxides; Particulate emissions; Pollutants; Roads & highways; Sulfur oxides; Trucks; Vehicles
• ISSN: 0094-243X; 1551-7616
• DOI: 10.1063/5.0130635

With the progression of a country, the number of vehicles increases and their composition varies very rapidly. Though these are essential for mobility, these have become a major concern for the overall environment as they pose adverse impacts on it. In this study, the effect of different types of vehicles plying on the highways on the surrounding air quality is analyzed. It focuses on the vehicle composition on a specific link of national highway: N106-1 or Chittagong-Rangamati Highway, a Bangladeshi national highway connecting Chittagong with Rangamati via Raozan Upazila & Hathazari Upazila. Vehicle composition data is taken from the surveys done by the RHD Division, Bangladesh from their RMMS Database. Emission factors are taken from the literature. For relating emission factors to vehicle composition, a simple mathematical function is used with three independent variables: No. of a certain type of vehicle on that road (AADT value), length of the road section traveled by that vehicle, and their emission factors. The dependent variable is the amount of a certain type of pollutant emitted daily. Pollutants considered in this study are-Nitrogen Oxides (NOx), Sulfur Oxides (SOx), Hydrocarbons (HC), Carbon Monoxide (CO) and Suspended Particulate Matter (SPM). For this link, trucks are the main contributor of pollution and contribute to 55% of NOx pollution and 68% of SOx pollution. Trucks are also the main contributor to SPM and CO pollution. The second highest contributor varies for specific types of pollution. Bus is the second highest contributor of NOx, SOx and SPM pollution but it has comparatively less impact on HC and CO pollution. The number of auto-rickshaws is the highest (56%) on the road and they mainly contribute to HC and CO pollution. The contribution of auto-rickshaws to other pollution is relatively insignificant. Motorcars plying on this highway section need less attention than the major vehicles using this road segment. These results illustrate the severity of the current operating modes of transportation for emitting different pollutants on the regional highways near Chittagong-Rangamati. These can certainly help the policy-makers to introduce preventive policies to different modes according to their emission level to reduce the overall pollution.