Analysis of remotely sensed and surface data of aerosols and meteorology for the Mexico Megalopolis Area between 2003 and 2015

Abstract

This paper presents an aerosol characterization study from 2003 to 2015 for the Mexico City Metropolitan Area using remotely sensed aerosol data, ground‐based measurements, air mass trajectory modeling, aerosol chemical composition modeling, and reanalysis data for the broader Megalopolis of Central Mexico region. The most extensive biomass burning emissions occur between March and May concurrent with the highest aerosol optical depth, ultraviolet aerosol index, and surface particulate matter (PM) mass concentration values. A notable enhancement in coarse PM levels is observed during vehicular rush hour periods on weekdays versus weekends owing to nonengine‐related emissions such as resuspended dust. Among wet deposition species measured, PM2.5, PM10, and PMcoarse (PM10‐PM2.5) were best correlated with NH4+, SO42−, and Ca2+, suggesting that the latter three constituents are important components of the aerosol seeding raindrops that eventually deposit to the surface in the study region. Reductions in surface PM mass concentrations were observed in 2014–2015 owing to reduced regional biomass burning as compared to 2003–2013.

On the Morphology and Composition of Particulate Matter in an Urban Environment

“…Reasons for high PM mass concentration include re-suspension of road dust, vehicular emissions, industrial emissions, brick kiln emissions, and residential combustion (Alam et al , 2011, 2015). In contrast, the following are PM values in other regions: PM 2.5 /PM 10 = 23.22 ± 4.72 μg m −3 /51.79 ± 12.63 μg m −3 in Mexico City between 2003–2015 (Mora et al , 2017), 28.4 ± 25.4/87.3 ± 47.3 μg m −3 in Jeddah (Saudi Arabia) (Khodeir et al , 2012), 32 ± 6/121 ± 12 μg m −3 in Udaipur, India in April 2010 (Yadav et al , 2014), 90/278 μg m −3 in Agra, India (Pipal et al , 2014), 21.82/39.45 μg m −3 in Shinjung, Taiwan (Gugamsetty et al , 2012), and 38 ± 12/70 ± 31 μg m −3 in townships in South Africa (Hersey et al , 2015). …”

Contamination Level, Source Identification and Risk Assessment of Potentially Toxic Elements (PTEs) and Polycyclic Aromatic Hydrocarbons (PAHs) in Street Dust of an Important Commercial Center in Iran

“…Street dust is the result of those emissions depositing on paved streets. In addition, particles that settle on the street from both nearby and distant sources can be subsequently resuspended by mechanical lifting, such as from vehicles or wind, as has been demonstrated in a number of areas, such as the Sonoran Desert (Prabhakar et al, 2014) and Mexico City (Mora et al, 2017). Consequently, street dust particles in urban areas are both a sink and source of contaminants such as potentially toxic elements (PTEs) and polycyclic aromatic hydrocarbons (PAHs) (Charlesworth et al 2003; Zhao et al 2006; Zhang and Wang 2009; Soltani et al 2015).…”

Characterizing Weekly Cycles of Particulate Matter in a Coastal Megacity: The Importance of a Seasonal, Size‐Resolved, and Chemically Speciated Analysis

“…T. Cruz et al, 2013;Moron et al, 2009). As an indicator for moisture and potential for aerosol aqueous processing (Mora et al, 2017;Youn et al, 2013), RH is highest in August, associated with the annual precipitation maximum at this time, and shows a secondary maximum in December, independent of precipitation ( Figure 1b). Incident solar radiation peaks in MAM and November (Figure 1c), whereas it exhibits a minimum in JJA, consistent with increased cloud cover and the annual maximum of precipitation during this time of year.…”

“…Intense burning emissions in MAM are indicated by the strength of local fire activity ( Figure S2b) and the sharp WC peak on Tuesday-Thursday in both total PM and key burning tracers (Figures 4c, 5b-5e, S4c, and S4d). Although the higher BLH in MAM (Figures 1d and 1e) may temper the WC baseline concentration to some degree via dilution within the mixing layer (Mora et al, 2017;Sheehan & Bowman, 2001;Tai et al, 2010), the intensity of emissions in MAM seems to be sufficient to counteract the dampening effects of meteorology on aerosol concentrations.…”