Methylsiloxanes from Vehicle Emissions Detected in Aerosol Particles

Author(s)

Yao, Peng ; Holzinger, Rupert ; Materic, Dusan ; Oyama, Beatriz Sayuri ; Andrade, Maria de Fatima ; Paul, Dipayan ; Ni, Haiyan ; Noto, Hanne ; Huang, Ru-Jin ; Dusek, Ulrike

• Document type: Journal article
• Source: Environmental Science & Technology; v. 57, n. 38, p. 11-pg., 2023-09-12.

Abstract

Methylsiloxanes have gained growing attention as emerging pollutants due to their toxicity to organisms. As man-made chemicals with no natural source, most research to date has focused on volatile methylsiloxanes from personal care or household products and industrial processes. Here, we show that methylsiloxanes can be found in primary aerosol particles emitted by vehicles based on aerosol samples collected in two tunnels in Sao Paulo, Brazil. The aerosol samples were analyzed with thermal desorption-proton transfer reaction-mass spectrometry (TD-PTR-MS), and methylsiloxanes were identified and quantified in the mass spectra based on the natural abundance of silicon isotopes. Various methylsiloxanes and derivatives were found in aerosol particles from both tunnels. The concentrations of methylsiloxanes and derivatives ranged 37.7-377 ng m(-3), and the relative fractions in organic aerosols were 0.78-1.9%. The concentrations of methylsiloxanes exhibited a significant correlation with both unburned lubricating oils and organic aerosol mass. The emission factors of methylsiloxanes averaged 1.16 +/- 0.59 mg kg(-1) of burned fuel for light-duty vehicles and 1.53 +/- 0.37 mg kg(-1) for heavy-duty vehicles. Global annual emissions of methylsiloxanes in vehicle-emitted aerosols were estimated to range from 0.0035 to 0.0060 Tg, underscoring the significant yet largely unknown potential for health and climate impacts. (AU)

• FAPESP's process: 12/21456-0 - Determination of the organic fraction in the fine particles emitted from the vehicular fleet in São Paulo City
• Grantee: Beatriz Sayuri Oyama
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• FAPESP's process: 11/17754-2 - Determination of the organic fraction in the fine particles emitted from the vehicular fleet in São Paulo city
• Grantee: Beatriz Sayuri Oyama
• Support Opportunities: Scholarships in Brazil - Doctorate