Research

Particulate matter (PM) has been identified as a health concern, but temporally well-resolved measurements that describe the composition of PM are lacking, particularly those of toxic metals. To fill the gap, we have developed a spark-induced breakdown spectroscopy instrument for the analysis of toxic metals in ambient PM (toxic-metal Aerosol Real Time Analyzer, TARTA). TARTA is inexpensive ($3,000), compact (1 ft cube), high time resolution (30 minutes), and power-efficient (< 30 W). The instrument can be used for monitoring metals in ambient air, occupational exposure assessment, and continuous emission monitoring of hazardous air pollutants at the point of emission (stack).

We conduct field-based, multi-pollutant emission characterization studies across diverse urban and rural environments, such as Imperial Valley, Los Angeles, San Diego, and Sacramento. By integrating advanced monitoring technologies and community-engaged research approaches, we aim to better understand the sources, transformations, and health impacts of air pollutants in complex atmospheric systems. 

Dr. Li's research also leverages data mining tools to address analytical challenges in aerosol studies. 

• Develop a correction algorithm using statistical approaches to minimize light absorption measurement artifact of filter-based absorption photometers. 

• Propose a machine learning-based model to predict the mass absorption cross-section (MAC) of BC aerosols from both ambient and BB environments. 

• Incorporate advanced data analytical techniques to improve the quantification of elemental concentration in spectroscopic analysis. 

In the aftermath of the LA fires in 2025, our team conducted a field-based study to assess indoor and outdoor air quality in affected homes. We focused on real-time measurements of PM, soot, and hazardous air toxics in residences that were damaged or partially destroyed by fire. We go beyond simply reporting numbers—each participating household receives personalized reports that include clear interpretations of the findings and tailored recommendations to support safe reoccupation and long-term recovery. An example of reports can be found here.