Assessment of Reliability when Using Diagnostic Binary Ratios of Polycyclic Aromatic Hydrocarbons in Ambient Air PM10.

Siwatt Pongpiachan

doi:10.7314/apjcp.2015.16.18.8605

Abstract

The reliability of using diagnostic binary ratios of particulate carcinogenic polycyclic aromatic hydrocarbons (PAHs) as chemical tracers for source characterisation was assessed by collecting PM10 samples from various air quality observatory sites in Thailand. The major objectives of this research were to evaluate the effects of day and night on the alterations of six different PAH diagnostic binary ratios: An/(An + Phe), Fluo/(Fluo + Pyr), B[a]A/(B[a]A + Chry), B[a]P/(B[a]P + B[e]P), Ind/(Ind + B[g,h,i]P), and B[k]F/Ind, and to investigate the impacts of site-specific conditions on the alterations of PAH diagnostic binary ratios by applying the concept of the coefficient of divergence (COD). No significant differences between day and night were found for any of the diagnostic binary ratios of PAHs, which indicates that the photodecomposition process is of minor importance in terms of PAH reduction. Interestingly, comparatively high values of COD for An/(An + Phe) in PM10 collected from sites with heavy traffic and in residential zones underline the influence of heterogeneous reactions triggered by oxidising gaseous species from vehicular exhausts. Therefore, special attention must be paid when interpreting the data of these diagnostic binary ratios, particularly for cases of low-molecular-weight PAHs.

Highlights

Over recent decades, major advances have been made in elucidating the environmental fate and behaviour of polycyclic aromatic hydrocarbons (PAHs) in various environmental situations (Pongpiachan, 2013a,b, 2014, 2015; Pongpiachan et al, 2013a,b,c, 2015a,b)
The reliability of using diagnostic binary ratios of particulate carcinogenic polycyclic aromatic hydrocarbons (PAHs) as chemical tracers for source characterisation was assessed by collecting PM10 samples from various air quality observatory sites in Thailand
The Spatial Distributions of PM10-bounded PAHs based on a Monitoring Campaign (SDPMC) were carefully assessed using seven air quality monitoring sites operated by the Pollution Control Department of the Ministry of Natural Resources and Environment, Thailand: Klongchan National Housing Authority (KHA; 13°49’11.761”N, 100°34’33.190”E), Nonsreewitayakom High School (NWS; 13°42’28.937”N, 100°32’50.443”E), Singharaj Pitayakhom High School (SPS), Thonburi Power Substation (TPS; 13°43’39.205”N, 100°29’11.776”E), Figure 1

Summary

Introduction

Major advances have been made in elucidating the environmental fate and behaviour of polycyclic aromatic hydrocarbons (PAHs) in various environmental situations (Pongpiachan, 2013a,b, 2014, 2015; Pongpiachan et al, 2013a,b,c, 2015a,b). The application of diagnostic binary ratios of PAH congeners to categorise their potential sources is a comparatively simple process, which provides a broad comprehensive perspective of source classification. For these particular reasons, diagnostic binary ratios of PAHs have been used widely as promising chemical tracers in marine deposits, terrestrial soils, atmospheric particles, and agricultural products (Tipmanee et al, 2012; Alam et al, 2013; Pongpiachan, 2014, 2015; Pongpiachan et al, 2015a,b)

Objectives

Methods

Results