Size-specific PAHs and Associated Health Risks over a Tropical Urban Metropolis: Role of Long-range Transport and Meteorology

Abstract

The polycyclic aromatic hydrocarbons (PAHs) are considered as an important class of organic pollutants in the urban atmosphere to pose serious health hazards. A comprehensive study was conducted during the dry seasons of 2017-2018 to understand the impacts of local sources, meteorology, boundary layer dynamics, and long-range transport, on the sizespecific particulate PAHs (Coarse: 10-2.1 µm; Superfine: 2.1-1.1 µm; Accumulation: 1.1-0.4 µm and Ultrafine: < 0.4 µm). Samples were collected over Kolkata (22.33°N and 88.20°E), a megacity of the lower Indo-Gangetic Plain (IGP). Wintertime distributions of all PAHs were exclusively unimodal with their maximum abundance in accumulation mode, whereas the 4,5 and 6-ring PAHs showed additional coarse mode peaks during post-monsoon and pre-monsoon. The Concentration Weighted Trajectory model has identified the middle IGP and the Eastern Ghats as the potent PAH source regions for the receptor site. Meteorology significantly influenced, in minimizing the contributions of transported PAHs from biomass burning regions of Eastern Ghats during pre-monsoon. On the contrary, meteorology favored the PAHs accumulation from local emissions and long-range transport during winter and post-monsoon. Source apportionment by positive matrix factorization model identified unburned petroleum, incineration, fossil fuel and coal burning as possible major sources of size-specific PAHs. Additionally, based on benzo(a)pyrene equivalent concentrations, the incremental lifetime cancer risk (ILCR) values were estimated for four human age groups. In general, ILCR values were influenced by the accumulation mode, and they were highest for all size ranges during winter. The estimated upper limit of ILCR (9.26 × 10-6) exceeding the carcinogenic benchmark level (1 × 10-6), draws attention towards the adverse impacts of wintertime ultrafine PAHs on human health in Kolkata, where poor air quality is already a major concern.

Wintertime Air Quality in Lumbini, Nepal: Sources of Fine Particle Organic Carbon

“…The winter season in the Indo-Gangetic Plains (IGP) is characterized by severe haze and high particulate matter (PM) concentrations. − Frequent exceedance of the PM level over the World Health Organization (WHO) guidelines is well documented. − Negative consequences of regional pollution events include exacerbations of respiratory and cardiovascular diseases, , increasing incremental lifetime cancer risk, − harm to agriculture, , and reduced visibility . Understanding the natural and anthropogenic sources and processes that contribute to airborne particulate matter (PM) is the focus of this study.…”

Summertime Characteristics of Atmospheric Polycyclic Aromatic Hydrocarbons in a Coastal City of Northern Poland

“…Atmospheric PAHs can exist in the gas phase and aerosol, which depends on their chemical structure and properties, but also complicated mechanisms of their formation/transformation [2,3]. Anthropogenic sources such as incomplete combustion of fossil fuel, industrial activities and traffic emissions can emit a substantial amount of volatile, semivolatile and non-volatile PAH compounds into the atmosphere over urban agglomerations [4,5]. In many urban areas, PAH emissions are of great concern due to their climatic, human health and environmental effects [6,7].…”