Exploring Meteorological Conditions and Human Health Impacts during Two Dust Storm Events in Northern Cape Province, South Africa: Findings and Lessons Learnt

Caradee Yael Wright,Thandi Kapwata,Vusumuzi Nkosi,David Jean du Preez,Angela Mathee,Rebecca Garland,Suzana Blesic,Zamantimande Kunene

doi:10.3390/atmos13030424

Abstract

Dust storms are meteorological hazards associated with several adverse health impacts including eye irritations, respiratory and cardiovascular disorders, and vehicular road accidents due to poor visibility. This study investigated relations between admissions from a large, public hospital that serves people living in Northern Cape and Free State provinces, South Africa during 2011 to 2017, and meteorological variables (temperature and air quality) during two dust storms, one in October 2014 (spring) and the second in January 2016 (summer), identified from the media as no repository of such events exists for South Africa. Distributed nonlinear lag analysis and wavelet transform analysis were applied to explore the relationships between hospital admissions for respiratory and cardiovascular diseases, eye irritation, and motor vehicle accidents; maximum temperature, and two air quality ‘proxy measures,’ aerosol optical depth and Ångström exponent, were used as ground-based air quality data were unavailable. Eye irritation was the most common dust-related hospital admission after both dust storm events. No statistically significant changes in admissions of interest occurred at the time of the two dust storm events, using either of the statistical methods. Several lessons were learnt. For this type of study, ground-based air quality and local wind data are required; alternative statistical methods of analysis should be considered; and a central dust storm repository would help analyze more than two events. Future studies in South Africa are needed to develop a baseline for comparison of future dust storm events and their impacts on human health.

Highlights

The frequency and intensity of dust storms has been increasing over the past decade [1–3].Forecasts project that their incidence will continue to increase because of both climate change and anthropogenic activities [4]
Given the dearth of these studies in South Africa, we aimed to consider the relationships between meteorological variables, namely temperature, tropospheric column aerosol optical depth, and Ångström Exponent observed during dust storm events of October 2014 and January 2016, and hospital admissions for respiratory and cardiovascular diseases, eye irritation, and motor vehicle accidents from a large, public hospital on the border of the Free State and Northern Cape provinces
We found a small increase in hospital admissions for eye irritation, an outcome that may be caused by dust exposure such as that experienced during a dust storm, up to 30 days after the occurrence of the dust storm

Summary

Introduction

The frequency and intensity of dust storms has been increasing over the past decade [1–3]. Forecasts project that their incidence will continue to increase because of both climate change and anthropogenic activities [4]. Dust storms occur from the combination of strong winds and loose dry soil surfaces in arid and semi-arid areas. Fine dust particles may be lifted high into the atmosphere and swept by strong winds in large amounts over long distances including across continents [5]. Depending on the weather conditions and particle size, dust can remain in the atmosphere for a few hours up to more than a week. Human activities, including changes in land-use and agricultural practices leading to erosion, influence the frequency and intensity of dust storms [6]

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