Evaluation of Variability in the Ambient PM2.5 Concentrations from FEM and FRM-like Measurements for Exposure Estimates

Yu-Cheng Chen,Mu-Jean Chen,Chin-Yu Hsu,Ching-Yi Mou

doi:10.4209/aaqr.2020.05.0217

Abstract

This study aims to evaluate the variability in ambient fine particulate matter (PM2.5) concentrations obtained from the federal equivalent method (FEM) and federal reference method (FRM)-like measurements at the national air quality monitoring stations (AQMSs) for exposure estimates and to examine the effect of environmental factors and sampling site characteristics affecting the spatial and temporal variations in PM2.5 concentrations. A mixed-effects model was used to evaluate the temporal and spatial variability in daily and annual PM2.5 concentrations during 2014-2017 at 16 AQMSs in the Big Taipei City, Taiwan. The mean FEM PM2.5 concentrations were ~30% higher than the FRM-like PM2.5 concentrations. The FRM-like PM2.5 concentrations obtained by applying the calibration procedures presented a negligible between-site variability. The daily FEM PM2.5 concentrations were dominated by the within-site variability (~90%), whereas the annual concentrations were reasonably attributable to the between-site variability (47.8%). Ambient PM2.5 was mainly affected by the gaseous pollutants (such as NO2, O3, and SO2), accounting for 45.8% and 26.8% of the within-site and between-site variability in concentrations, respectively. The FEM measurements rather than the FRM-like measurements at the AQMSs could provide a higher between-site variability for exposure estimates of PM2.5 in the epidemiological studies.

Highlights

The elevated levels of fine particulate matter (PM2.5) are associated with adverse health effects, such as respiratory and cardiovascular morbidity and mortality, which have been reported in many studies (Beelen et al, 2014; Cai et al, 2016; Kaufman et al, 2016)
This study aims to evaluate the variability in ambient fine particulate matter (PM2.5) concentrations obtained from the federal equivalent method (FEM) and federal reference method (FRM)-like measurements at the national air quality monitoring stations (AQMSs) for exposure estimates and to examine the effect of environmental factors and sampling site characteristics affecting the spatial and temporal variations in PM2.5 concentrations
This study aims to evaluate PM2.5 variability in FRM-like and FEM measurements and identify the important factors affecting within- and between-site (-group) variability in PM2.5 concentrations in the metropolitan area

Summary

Introduction

The elevated levels of fine particulate matter (PM2.5) are associated with adverse health effects, such as respiratory and cardiovascular morbidity and mortality, which have been reported in many studies (Beelen et al, 2014; Cai et al, 2016; Kaufman et al, 2016). Recent literature has documented that exposure to even low levels of PM2.5 can significantly increase all-cause mortality (Shi et al, 2016). National ambient air quality standards (NAAQS) are usually regulated in many countries to limit air pollution (such as ambient PM2.5 levels) and protect public health. The annual (15 μg m–3) and daily (35 μg m–3) standards of PM2.5 have been set by Taiwan EPA while lower guideline limits for outdoor PM2.5 (annual = 10 μg m–3, daily = 25 μg m–3) have been suggested by WHO. The filter-based instruments such as BGI PQ200 and RAAS2.5 single and multi-day samplers are usually used for consistent

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