Grantee Research Project Results

Low-Cost Methods for Black Carbon Source Apportionment

EPA Grant Number: SU841122
Title: Low-Cost Methods for Black Carbon Source Apportionment
Investigators: Presto, Albert
Institution: Carnegie Mellon University
EPA Project Officer: Callan, Richard
Phase: I
Project Period: March 1, 2025 through February 28, 2027
Project Amount: $75,000
RFA: 21st Annual P3 Awards: A National Student Design Competition Focusing on People, Prosperity, and the Planet Phase I (2024) RFA Text
Research Category: P3 Awards , Air Quality and Air Toxics , Health Effects , Particulate Matter , Human Health , Air , P3 Challenge Area - Air Quality , Environment

Description:

The overall goal is to take our existing cellphone-based black carbon (BC) detection method and add the functionality that we can apportion the BC into fossil fuel and biomass burning contributions. To do this, we will need data for training a source apportionment algorithm. We will therefore start by collecting the data necessary to train the new algorithm. We will: (1) Obtain filter samples for periods in 2023 that were impacted by the Canadian wildfires. This will let us do a 1-to-1 comparison of our revised algorithm with existing high-cost methods for determining the split between biomass burning and fossil fuel BC. (2) We will generate new samples in the lab and field. For example, we will use our smog chamber to sample wood smoke, diesel exhaust, and mixtures of the two, as well as to create ambient filter samples ‘doped’ by laboratory-generated wood smoke and diesel exhaust. Once we have enough training data, we will develop and train the new algorithm. We will test the performance of the new algorithm by performing both a 10-fold cross validation and by holding back a portion of the available data as a test set. Lastly, we will use our algorithm on real samples deployed in communities.

Objective:

The goal of this proposal is to develop a low-cost method for community-scale measurement and source apportionment of black carbon (BC) in fine particulate matter (PM_2.5). BC is a component of PM_2.5 that is emitted from all combustion systems. It is therefore both a marker for combustion emissions and it contributes to the PM_2.5 exposure burden borne by communities.

Approach:

We have already developed a low-cost, cellphone-based method for BC quantification. This project will expand that work to create a method for performing source apportionment of BC, and PM_2.5 more broadly, between fossil fuel and biomass burning sources. Application of this method will in turn enable both regulatory agencies and communities to better understand their exposures and to create data-driven change. This project will meet the following specific objectives: (1) Develop an algorithm that can use our existing cellphone-based method to determine fossil fuel and biomass burning contributions to BC. (2) Apply this algorithm to samples collected in various environments, including from overburdened communities. 

Expected Results:

The primary outcome of this project will be a low-cost method for determining the concentrations and sources of BC. This method will be deployable in communities and will allow community members to build evidence-based arguments for change. We will partner with at least one community group in Pittsburgh to teach them how to use this method and to help quantify their own exposures. This project will help address knowledge gaps in how to apply low-cost methods to collect policy-relevant data that can be used to advocate for change. Many communities have begun using low-cost sensors for PM_2.5 monitoring, but these sensors do not provide information on PM_2.5 sources. Our approach expands on those efforts, at very low cost, in a way that provides the source specificity needed to inform revised policies that will reduce exposures.

Supplemental Keywords:

particulate matter, exposure, ambient measurement, source apportionment, black carbon, aerosol, air quality