On the diurnal variability of particle properties related to light absorbing carbon in Mexico City
Open Access
- 14 May 2007
- journal article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 7 (10), 2517-2526
- https://doi.org/10.5194/acp-7-2517-2007
Abstract
The mass of light absorbing carbon (LAC) in individual, internally mixed aerosol particles was measured with the Single Particle Soot Photometer (SP2) in April of 2003 and 2005 and evaluated with respect to concentrations of carbon monoxide (CO), particle bound polycyclic aromatic hydrocarbons (PPAH) and condensation nuclei (CN). The LAC and CO have matching diurnal trends that are linked to traffic patterns and boundary layer growth. The PPAH reaches a maximum at the same time as CO and LAC but returns rapidly back to nighttime values within three hours of the peak. The number of particles containing LAC ranges between 10% to 40% of all particles between 150 nm and 650 nm and the mass is between 5% and 25% of the total mass in this size range. The average LAC equivalent mass diameter varies between 160 and 230 nm and the thinnest coating of non-light absorbing material is observed during periods of maximum LAC mass. The coating varies between 10 nm and 30 nm during the day, but is a strong function of particle size. The mass absorption cross sections, σabs, derived from the SP2, are 5.0±0.2 m2g−1 and 4.8±0.2 m2g−1, dependent on the optical model used to describe LAC mixtures. The LAC contributes up to 50% of the total light extinction in the size range from 100 nm to 400 nm. The estimated emission rate of LAC is 1200 metric tons per year in Mexico City, based upon the SP2 measurements and correlations between LAC and CO.This publication has 35 references indexed in Scilit:
- Estimation of a "radiatively correct" black carbon specific absorption during the Mexico City Metropolitan Area (MCMA) 2003 field campaignAtmospheric Chemistry and Physics, 2007
- Limitations in the enhancement of visible light absorption due to mixing stateJournal of Geophysical Research: Atmospheres, 2006
- Light Absorption by Carbonaceous Particles: An Investigative ReviewAerosol Science and Technology, 2006
- Size distributions and mixtures of dust and black carbon aerosol in Asian outflow: Physiochemistry and optical propertiesJournal of Geophysical Research: Atmospheres, 2004
- Warming of the Arctic lower stratosphere by light absorbing particlesGeophysical Research Letters, 2004
- Diagnosing black carbon trends in large urban areas using carbon monoxide measurementsJournal of Geophysical Research: Atmospheres, 2002
- On the evolution of aerosol properties at a mountain site above Mexico CityPublished by American Geophysical Union (AGU) ,2000
- Calibration and Intercomparison of Filter-Based Measurements of Visible Light Absorption by AerosolsAerosol Science and Technology, 1999
- The Impact of Aerosols on Solar Ultraviolet Radiation and Photochemical SmogScience, 1997
- Climate Forcing by Anthropogenic AerosolsScience, 1992