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Welcome

Welcome to the UK Natural Dust and Health Network homepage.

Ruapehu
Mt Ruapehu, New Zealand

The Dust & Health Network comprises researchers in the UK who are interested in all aspects of the health hazards of natural mineral dusts.

We are funded by NERC's Environment & Human Health Programme ("A network for the study of the properties and respiratory health effects of natural mineral dust" NE/E008712/1).

 

Who are we?

The Network is built around a core membership representing environmental health and medicine, toxicology, mineralogy, volcanology and atmospheric science. Other UK and international experts will contribute to a wide exchange of views on topics including risk perception and environmental policy, regulatory issues and contingency planning for an air pollution event. The network fosters collaborative exchange on a wide range of health-related aspects of natural mineral particles (NMPs). Key areas covered are:

  • Exposure – source, dispersion and atmospheric chemistry of plumes containing NMPs
  • Toxicity – mineralogy, size spectrum, transformations, surface reactivity and interactions of particles with gas and aqueous phases
  • Policy – health risk assessment for community and occupational exposures to NMPs; public risk perception; legislative implications
  • Role of scientists in planning for air pollution episodes involving NMPs (natural experiments)

The Network addresses all NMPs whilst exploiting the insights that can be obtained from the advances in research on volcanic particles, including ultra-fines. Volcanoes provide natural laboratories for the study of natural particle generation, transport, chemical transformations, and their variable surface properties and composition.

 

Background

We are exploring three inter-related themes on the health effects of particles:

(i) Exposure to natural particles through indoor and outdoor air pollution

Recent work on particle toxicity has focused on particle size and composition, and surface properties. Epidemiological and toxicological studies have identified the toxic fractions of airborne particles as residing in the PM10 and PM2.5 size distributions, but these apply primarily to combustion particles, whereas NMPs have been regarded as significantly less toxic. However, the toxicity of fine and ultrafine NMPs erupted by volcanoes or generated from other natural sources and their interactions with other pollutants, warrant further study. Massive dust storms occur seasonally in regions including the Middle East and Sahara, and parts of western and northern Asia, including North China, where the exposed population has been estimated at 24 million. The processes by which metals bound to rock dusts initiate patho-physiological responses are poorly understood, e.g., in Saharan dust that falls across much of the north Atlantic region.

(ii) Occupational exposure to natural particles and work exposure limits

Crystalline silica is responsible for silicosis and it is also a human lung carcinogen. It is the commonest fibrogenic constituent of natural dusts. US and UK regulators have been recently seeking to revise the work exposure limit for crystalline silica, but were hampered by a lack of scientific understanding of what makes silica particles pathogenic. Exposure to a wide range of different NMPs is still common in many industrial processes, but understanding of the health risks has slowly developed and been dependent on the results of epidemiological studies of large groups of workers. The limits to finding large cohorts of heavily-exposed workers nowadays means that future developments in evaluating the health risks of particles, including the new nanotechnologies and siliceous or other natural dusts, will depend more on an improved understanding of the physico-chemical surface factors that underlie toxicity.

(iii) Volcanic particles: a natural laboratory for the study of natural particle toxicity and risk.

Volcanic plumes provide a mixture of gas and particle phases that interact in complex ways with atmospheric species, especially oxidants. The Soufrière Hills volcano, Montserrat, West Indies, has been erupting since 1995, exposing workers and the general population to respirable NMPs containing cristobalite whose toxicity may depend on eruptive style, ageing and dispersion (Baxter et al., 1999). Respirable-sized ash samples tested in vitro and in vivo showed a lower toxicity than would be expected from the cristobalite concentration alone and an expert group attributed this to its resemblance to “mixed-dusts” of natural origin (Hincks et al., 2006). Horwell et al. (2003) have measured free radicals and abundant Fe2+ on fresh ash particles, and shown that these surface properties could contribute to toxicity. The atmospheric chemistry of volcanic plumes is a growing area of research at the interface between volcanology and atmospheric science, and one that overlaps with our own interests on the fate of NMPs. In addition, atmospheric dispersion modeling is critical to prediction of human exposure to ash fall and resuspension (Hincks et al., 2006).

References: Baxter et al. 1999. Science 283: 1142-1145; Hincks et al., 2006. Bull Volcanol. 68: 266-284; Horwell et al., 2003. Env. Res. 93, 202-215.

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