10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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On Particle-Bound Polycyclic Aromatic Hydrocarbons (PPAH) and Links to Gaseous Emissions in Mexico City
LUIS ANTONIO LADINO, Graciela Raga, Darrel Baumgardner, Universidad Nacional Autónoma de México, Mexico City, Mexico
Abstract Number: 949 Working Group: Air Quality in Megacities: from Sources to Control
Abstract Mexico City is a densely populated megacity with average PM10 and PM2.5 levels frequently above those indicated as health threatening for humans by the World Health Organization. Polycyclic aromatic hydrocarbons (PAH) can be emitted by anthropogenic sources as the result of the incomplete combustion of organic matter and fossil fuels and they represent an important risk for human health under poor air quality conditions. High concentrations of PAHs have been linked with cancer and other respiratory diseases. Although particle-bound PAHs (PPAHs) have been previously studied in Mexico City, their temporal scales are not fully understood given the short sampling periods (up to five weeks) during which they were evaluated.
Recent, automated and continuous measurements of PPAH concentration made in Mexico City during one full year (April, 2016 to March, 2017) show average PPAH concentration of 31.7±29.9 ng m-3 at the sampling location. The highest concentrations were observed in winter. On a daily basis, the maximum concentrations were observed between 6:00 and 11:00 am, as high as 352 ng m-3. The average PPAHs levels measured in spring 2016 were found to be ca. 50% higher than those that were previously measured in spring 2003, in approximately the same location. Given the lack of instrumentation to measure PPAH at most air quality monitoring stations, a proxy was developed based upon the concentrations of carbon monoxide (CO) and nitrous oxides (NOx), which are typically measured at urban monitoring stations worldwide. Such parametrizations suggest that people living in the North and Northeast of Mexico City are at higher risk to develop respiratory problems given that in these locations the PPAH concentrations are expected to be higher than in the rest of the city.