Estimation of global vehicular methyl bromide emissions: Extrapolation from a case study in Santiago, Chile

• Published in: Geophysical research letters 1999-02, Vol.26 (3), p.283-286
• Main Authors: Chen, Tai-Yih, Blake, Donald R., Lopez, Jimena P., Rowland, F. Sherwood
• Format: Article
• Language: English
• Subjects: Applied sciences; Atmospheric pollution; Chemical composition and interactions. Ionic interactions and processes; Earth, ocean, space; Exact sciences and technology; External geophysics; Meteorology; Pollutants physicochemistry study: properties, effects, reactions, transport and distribution; Pollution
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/1998GL900214

Between June 1 and June 8, 1996, 144 whole air samples were collected in Santiago, Chile. The temporal and geographical enhancement of CH3Br correlated with incomplete combustion tracers emitted from vehicles during the morning commute. From these, a city‐wide CH3Br/CO volume emission ratio of 2.2 × 10−6 was measured in ambient air. Without using the CO measurements, we estimate an annual release of 8.9 tons of CH3Br in Santiago based solely upon enhanced concentrations observed throughout the study area during the morning traffic period. This enhancement corresponds to 8.0 × 10−6 kg CH3Br emitted for each liter of gasoline used (leaded and unleaded). By scaling the annual gasoline usage in Santiago to countries still using leaded gasoline, and assuming the above 8.0 × 10−6 kg/L value holds true, a global vehicular CH3Br emission of 4 ± 3 Gg/year is calculated. This small vehicular CH3Br emission source strength will not improve the current CH3Br budget imbalance.