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This research study focuses on the coupling between particulate matter and the planetary boundary layer. Particulate matter affects human health and it is a complex mixture of suspended substances. Various sources of particulate matter include volcanic eruptions, soil lofted by strong winds, wildfires, and particles formed from chemical reactions of gas-phase emissions. Strong winds are one source of dust pollution when they loft soil particles. Particulate matter and the planetary boundary layer are closely linked. The planetary boundary layer plays a critical role in meteorology and particulate matter concentrations due to its involvement in energy, latent heat, and mass transfer with the free troposphere. Currently, there has been no research on the impact of dust events on the planetary boundary layer in our region, El Paso, Texas, which is located on one of the biggest sources of dust in the Western Hemisphere, the Chihuahuan Desert. In this study, we used PM10 concentrations to detect dust events during the 2016–2022 period in the El Paso region. During the study period, we observed 74 dust events. The dust events were categorized as synoptic or convective cases. Synoptic cases are associated with cold fronts, while convective cases are associated with local convective systems such as thunderstorms. We observed that synoptic cases occurred most frequently during springtime, while convective cases were more frequent during summer monsoon months. Synoptic cases tend to occur earlier in the afternoon with lower temperatures, while convective cases tend to occur in the late evening with higher temperatures. We also found that the planetary boundary layer height collapsed after the maximum hourly PM10 concentration and then the boundary layer returned to its original height. [ABSTRACT FROM AUTHOR]

Ozone pollution has been prevalent in the El Paso-Juárez Airshed (EPJA), especially in the past few decades, and it has been on the rise recently. The spatial and temporal distribution of the tropospheric ozone and several key meteorological factors that influence its concentration has not been adequately understood. Therefore, this investigation comprehensively examined 57 high and 48 low ozone episodes occurring in this region during 2013–2019. We found that the interannual ozone concentration in EPJA was strongly affected by anthropogenic emissions. On the other hand, seasonal ozone variations are due to meteorological variables (among them, solar radiation, planetary boundary layer, and winds) in addition to biogenic emission factors. High ozone events are characterized by calm winds, shallow planetary boundary layer (PBL), whereas low ozone events were marked with strong winds, precipitation, and deep PBL. Synoptic and mesoscale wind patterns for these ozone episodes were identified and characterized. Most of the high ozone episodes occurred when an anticyclonic circulation aloft was associated with a 500-mile middle and upper tropospheric high-pressure region over the EPJA. During these events, stable air masses with convective available potential energies (CAPE) values of less than 450 J/kg were found. The importance of surface topography is illustrated by the fact that stations close to the Rio Grande River show a bimodal distribution of wind direction according to the valley axis. High ozone episodes occur with a surface easterly wind that is decoupled from winds above the Franklin mountains. [ABSTRACT FROM AUTHOR]

The adjacent cities of El Paso in Texas, USA, and Juarez in Mexico commonly experience pollution episodes, especially during the summer months. In the summer of 2017, successive high and low ozone episodes were observed. Aerosol backscattered data from a laser ceilometer was used to monitor and continuously measure the aerosol-layer characteristics. Meteorological parameters together with the aerosol layer height were used to determine the reason behind these successive high and low ozone events. In our research, both modelling and experimental data of the planetary boundary layer height (PBLH) were obtained and related to atmospheric stability. Aerosol backscatter data was used to investigate the structure, evolution, and influence of the top of the aerosol layer, which is a proxy for PBLHs. A shallow aerosol layer height (1164 ± 59 m) was observed during the high ozone episodes, in contrast to a deep aerosol layer (1990 ± 79 m) during the low ozone episodes. The ozone precursors, the ozone, and the ground-level aerosol concentrations were also examined during these episodes. It was observed that when the ozone was high, the PM2.5 was high, and when the ozone was low, the PM10 concentrations were high. Analysis of the wind patterns and synoptic scale meteorology also contributed to a better explanation of the nature of these events. [ABSTRACT FROM AUTHOR]