Ambient sampling of real-world residential wood combustion plumes

ABSTRACT

Wood smoke contains large quantities of carbonaceous aerosols known to increase climate forcing and be detrimental to human health. This paper reports the findings from our ambient sampling of fresh residential wood combustion (RWC) plumes in two heating seasons (2015–2016, 2016–2017) in Upstate New York. An Aethalometer (AE33) and a pDR-1500 were employed to monitor residential wood smoke plumes in Ithaca, NY through a hybrid mobile-stationary method. Fresh wood smoke plumes were captured and characterized at 13 different RWC sources in the city, all without significant influence from other combustion sources or atmospheric aging. Wood smoke absorption Ångström exponent (AAE) was estimated using both a one-component model, AAE_WB, and a two-component model, AAE_BrC (assuming AAE_BC = 1.0). Consistent with the recent laboratory studies, our results show that AAEs were highly variable for residential wood smoke for the same source and across different sources, with AAE_WB values ranging from 1.3 to 5.0 and AAE_BrC values ranging from 2.2 to 7.4. This finding challenges the use of using a single AAE wood smoke value within the range of 1 to 2.5 for source apportionment studies. Furthermore, the PM_2.5/BC ratio measured using optical instruments was demonstrated to be potentially useful to characterize burning conditions. Different wood smoke sources can be distinguished by their PM_2.5/BC ratio, which range between 15 and 150. This shows promise as an in-situ, cost-effective, ambient sampling-based method to characterize wood burning conditions.

Implications: There are two main implications from this paper. First, the large variability in wood smoke absorption Ångström exponent (AAE) values revealed from our real-world, ambient sampling of residential wood combustion plumes indicated that it is not appropriate to use a single AAE wood smoke value for source apportionment studies. Second, the PM2.5/BC ratio has been shown to serve as a promising in-situ, cost-effective, ambient sampling-based indicator to characterize wood burning conditions. This has the potential to greatly reduce the costs of insitu wood smoke surveillance.

Acknowledgment

The authors acknowledge funding support from the New York State Energy Research and Development Authority (NYSERDA), and appreciate the assistance of Ye Lin Kim, Ye Xie and Qikun Wang at Cornell University with conducting the field measurements. The New York State Department of Environmental Conservation (NYSDEC) provided forecasting support for mobile measurements, and the authors thank Robert Gaza, John Kent and Julia Stuart for their kind assistance. The authors also thank Magee Scientific for loaning the Aethalometer Model AE33 employed in the field measurements and Dr. James Schwab from the Atmospheric Science Research Center at University at Albany for valuable assistance. AFL would like to acknowledge his support from the Engineering Learning Initiative (ELI) at Cornell University.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available from the corresponding author, Dr. K. Max Zhang, upon reasonable request.

Supplementary material

Supplemental data for this paper can be accessed on the publisher’s website

Additional information

Funding

The work was supported by the New York State Energy Research and Development Authority [123059].

Notes on contributors

Alexander F. Li

Alexander F. Li completed his B.S. degree at Cornell University where he studied electrical and computer engineering and participated in environmental research. He earned a Master’s degree at Tsinghua University as a Schwarzman Scholar where he studied U.S.-China climate cooperation.

K. Max Zhang

K. Max Zhang is a professor of mechanical engineering at Cornell University, Ithaca, NY, USA.

George Allen

George Allen is the Chief Scientist at the Northeast States for Coordinated Air Use Management, Boston, MA, USA.

Shaojun Zhang

Shaojun Zhang was an Atkinson Postdoctoral Fellow at Cornell University. He is currently an assistant professor at School of Environment, Tsinghua University, China.

Bo Yang

Bo Yang was a postdoctoral researcher at Cornell University after receiving his PhD degree in mechanical engineering at the same institution. He is currently working at 3M.

Jiajun Gu

Jiajun Gu is currently a postdoctoral researcher at Cornell University after receiving her PhD degree in mechanical engineering at the same institution.

Khaled Hashad

Khaled Hashad received his PhD degree in mechanical engineering at Cornell University. He is currently working at Exponent, Inc.

Jeffrey Sward

Jeffery Sward received his PhD degree in mechanical engineering at Cornell University. He is currently working at Rocky Mountain Institute.

Dirk Felton

Dirk Felton is currently employed by the New York State Department of Environmental Conservation (NYSDEC) as a Research Scientist IV, where he oversees the air toxics monitoring program.

Oliver Rattigan

Oliver Rattigan is employed as a Research Scientist with the New York State Department of Environmental Conservation (NYSDEC) working on ambient air pollution monitoring.