Joint measurements of PM&amp;lt;sub&amp;gt;2. 5&amp;lt;/sub&amp;gt; and light-absorptive PM in woodsmoke-dominated ambient and plume environments

K Max Zhang,George Allen,Dirk Felton,James Schwab,Geng Chen,Oliver Rattigan,Jiajun Gu,Bo Yang

doi:10.5194/acp-17-11441-2017

Abstract

Abstract. DC, also referred to as Delta-C, measures enhanced light absorption of particulate matter (PM) samples at the near-ultraviolet (UV) range relative to the near-infrared range, which has been proposed previously as a woodsmoke marker due to the presence of enhanced UV light-absorbing materials from wood combustion. In this paper, we further evaluated the applications and limitations of using DC as both a qualitative and semi-quantitative woodsmoke marker via joint continuous measurements of PM2. 5 (by nephelometer pDR-1500) and light-absorptive PM (by 2-wavelength and 7-wavelength Aethalometer®) in three northeastern US cities/towns including Rutland, VT; Saranac Lake, NY and Ithaca, NY. Residential wood combustion has shown to be the predominant source of wintertime primary PM2. 5 emissions in both Rutland and Saranac Lake, where we conducted ambient measurements. In Ithaca, we performed woodsmoke plume measurements. We compared the pDR-1500 against a FEM PM2. 5 sampler (BAM 1020), and identified a close agreement between the two instruments in a woodsmoke-dominated ambient environment. The analysis of seasonal and diurnal trends of DC, black carbon (BC, 880 nm) and PM2. 5 concentrations supports the use of DC as an adequate qualitative marker. The strong linear relationships between PM2. 5 and DC in both woodsmoke-dominated ambient and plume environments suggest that DC can reasonably serve as a semi-quantitative woodsmoke marker. We propose a DC-based indicator for woodsmoke emission, which has shown to exhibit a relatively strong linear relationship with heating demand. While we observed reproducible PM2. 5–DC relationships in similar woodsmoke-dominated ambient environments, those relationships differ significantly with different environments, and among individual woodsmoke sources. Our analysis also indicates the potential for PM2. 5–DC relationships to be utilized to distinguish different combustion and operating conditions of woodsmoke sources, and that DC–heating-demand relationships could be adopted to estimate woodsmoke emissions. However, future studies are needed to elucidate those relationships.

Highlights

Woodsmoke resulting from anthropogenic activities is a widespread air pollution problem in many parts of the world
It is reported that around 35 % of total fine particulate matter (PM2.5) emissions in the United Kingdom came from domestic wood burning in 2015, while road transport only contributed around 13 % of the total PM2.5 emissions (DEFRA, 2016)
As mentioned in Sect. 2.2.1, we collocated a pDR-1500 with BAM 1020, which is a Federal Equivalent Method (FEM) PM2.5 sampler, from December 2011 to April 2012 at the Rutland site

Summary

Introduction

Woodsmoke resulting from anthropogenic activities is a widespread air pollution problem in many parts of the world. Residential woodsmoke is estimated to account for 20 % of total stationary and mobile polycyclic organic matter emissions, and 50 % of all areasource air-toxic cancer risks according to the 2011 National Air Toxics Assessment in the US (https://www.epa.gov/ national-air-toxics-assessment). It is reported that around 35 % of total fine particulate matter (PM2.5) emissions in the United Kingdom came from domestic wood burning in 2015, while road transport only contributed around 13 % of the total PM2.5 emissions (DEFRA, 2016). In addition to its contribution to regional air quality, residential woodsmoke may cause significant near-source air-quality impacts due to rela-. While in some sense wood burning products may be considered natural substances, the health effects of wood smoke are found to be comparable to those of fossil-fuel combustion sources (Naeher et al, 2007)

Objectives

Results

Conclusion