Regime shift in secondary inorganic aerosol (SIA) formation
Integrating observations from multiple observation networks and conducting aerosol thermodynamic simulations, I revealed a regime shift in SIA formation in the rural US. I showed that aerosol formation has become insensitive to NH3 perturbations across the rural US, indicating the lack of regulatory incentives of NH3 emission controls for air quality purposes. Meanwhile, emitted NH3 partitioned more into the gas phase. The annual mean molar fraction of gaseous NH3 in total ammonium (NH3 + NH4+) increased from 30 – 40% to 60 – 70% between 2011 – 2019. Because gaseous NH3 deposits faster than particulate NH4+ in aerosols, the regime shift also impacted spatial and temporal patterns of nutrient distribution, explaining aforementioned increasing trends in NH3 dry deposition, with impacts on the C cycle and ecosystem warranting further investigation.
Evaluation of NH3 Bidirectional Flux Models
Using the observations we and our collaborator made, we are evaluating and constraining NH3 bidirectional flux models. We are developing a Bayesian calibration framework using the Markov Chain Monte Carlo.
Redistribution of Air Pollutants by International Trade
International trade affects global air pollution and transport by redistributing emissions related to the production of goods and services and by potentially altering the total amount of global emissions. The paper I jointly first-authored coupled a chemical transport model and an economic model and demonstrated the importance of such redistribution for the first time by combining macroeconomic tools and atmospheric chemistry modeling. It received the 2015 Cozzarelli Prize by PNAS and led to multiple follow-up studies.
