1. Department of Environmental and Occupational Health, School of Public Health, University of Nevada, Las Vegas, Las Vegas, Nevada 89154, United States
2. Division of Atmospheric Sciences, Desert Research Institute, Reno, Nevada 89512, United States
3. Institute of Earth Environment, Chinese Academy of Sciences, Xi’an 710061, China
4. Department of Chemistry and Biochemistry, University of Alaska, Fairbanks, Alaska 99775, United States