Particle size distribution and particulate matter concentrations during synoptic and convective dust events in West Texas

Abstract

Abstract. Dust events are an important and complex constituent of the atmospheric system that can impact Earth's climate, the environment, and human health. The frequency of dust events in the Southern High Plains of West Texas has increased over the past 2 decades, yet their impact on air quality in this region is still unclear. This is due to the fact that there is only one air quality monitoring station that measures only PM2.5 concentrations (particulate matter with an aerodynamic diameter < 2.5 µm), and there is no information on other PM sizes or the particle size distribution. The Aerosol Research Observation Station (AEROS) unit provides insight into the local variation in particle concentration during different dust events and allows for a better understanding of the impact of dust events on air quality. As this area is prone to dust events, we were wondering if dust events generated by different meteorological causes (synoptic vs. convective) would present similar particle concentrations or particle size distributions. Thus, in this project, three different dust events were measured by AEROS and compared. Each dust event originated from a different direction and lasted a different duration. One of the dust events was synoptic (10 April 2019) and two were convective (5 and 21 June 2019). Measurements of particle mass and number concentration, size distribution, and meteorological conditions for each dust event were compared. The synoptic dust event (on 10 April) was longer (12 h) and had stronger wind speed conditions (up to 22.1 m s−1), whereas the two respective convective dust events on 5 and 21 June lasted only 20 and 30 min and had lower wind speeds (up to 16.5 and 13.4 m s−1). Observation of PM based on daily and hourly values showed an impact on air quality, yet measurements based on daily and hourly values underestimate the impact of the convective dust events. Observations based on a shorter timescale (10 min) reveal the true impact of the two convective dust events. A comparison of the particle size distribution showed that all three dust events presented an increase in particles in the 0.3–10 µm size range. Comparisons of the particle concentration for particles > 5 and > 10 µm show very high values during the dust events. Some particle sizes even increase in concentration by ∼ 2 orders of magnitude compared with the time before the dust event. This leads us to speculate that the impact of convective dust events on air quality in this region is underestimated with the current (hourly basis) method.

When a Dust Storm Is Not a Dust Storm: Reliability of Dust Records From the Storm Events Database and Implications for Geohealth Applications

“…Dust storm (DS) is a meteorological phenomenon caused by wind erosion of soil/sediment or suspension of particles from the land surface into the air by mechanical means (Goudie, 2014 ; Middleton, 2017 ). Dust particles are one of the most important natural contributors to atmospheric particulate matter (PM; PM 2.5 and PM 10 , particulate matter with an aerodynamic diameter <2.5 and 10 μm, respectively) (Ardon‐Dryer & Kelley, 2022 ; Kelley et al., 2020 ; Shahsavani et al., 2012 ). The increase of dust particles during dust events can affect solar radiation by absorbing and scattering the sun's radiation (Haywood et al., 2003 ), influence the atmospheric vertical electric field (Ardon‐Dryer et al., 2022 ), influence cloud formation (Ardon‐Dryer & Levin, 2014 ; Bangert et al., 2012 ), have detrimental effects on the global economy (Tozer & Leys, 2013 ), as well as impact human well‐being, safety, and health (Ardon‐Dryer et al., 2020 ; Goudie, 2014 ).…”

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Dust storm (DS) is a meteorological phenomenon caused by wind erosion of soil/sediment or suspension of particles from the land surface into the air by mechanical means (Goudie, 2014;Middleton, 2017). Dust particles are one of the most important natural contributors to atmospheric particulate matter (PM; PM 2.5 and PM 10 , particulate matter with an aerodynamic diameter <2.5 and 10 μm, respectively) (Ardon-Dryer & Kelley, 2022;Kelley et al, 2020;Shahsavani et al, 2012). The increase of dust particles during dust events can affect solar radiation by absorbing and scattering the sun's radiation (

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Atmospheric aerosol particles before, during, and after a convective dust event on the Jornada experimental range as measured using Raman hyperspectral imaging

“…19 Additionally, aerosol concentrations can change rapidly, so a 10-min time-resolution may be needed to resolve aerosol changes before, during, and after a dust event. 19 The compositions of particulates during convective dust events are needed for understanding potential health, visibility, and climate impacts. However, timeresolved measurements of aerosol composition before, during, and after dust storms in desert environments where local dust can be lofted are not common.…”

Performance evaluation of the Alphasense OPC-N3 and Plantower PMS5003 sensor in measuring dust events in the Salt Lake Valley, Utah

“…Our changing climate is expanding the extent of arid and semi-arid lands globally; these lands currently cover approximately 1/3 rd of the Earth's land surface (Williams et al, 2022;Huang et al, 2016). Recent studies suggest that this expansion of arid lands is linked to increases in the number and severity of dust events (Clifford et al, 2019;Tong et al, 2017;Ardon-Dryer and Kelley, 2022). Dust events can transport particulate matter (PM), particle-bound air toxics, and allergens over thousands of kilometers (Goudie, 2014).…”

“…The WHO has set guidelines for 24-hour and annual average PM10 concentration at 45 and 15 µg/m 3 , respectively (WHO, 2022). One challenge with these 24-hour guidelines is that dust events often last a few hours, and these events are obscured when reporting only the PM10 24-hour average or comparing these averages to the 24-hour and guidelines (Ardon-Dryer and Kelley, 2022).…”