Exposure to crystalline silica in volcanic ash is typically of short duration (days to weeks), and studies suggest that the recommended exposure limits (similar in most countries) can be exceeded for short periods of time for the general population. For these diseases to occur, the ash must be very fine, contain crystalline silica (for the disease silicosis to occur) and the people must be exposed to the ash in high concentrations over many years. In rare circumstances, long-term exposure to fine volcanic ash may lead to serious lung diseases.
#Projectile effects are a hazard in skin
What are the effects of ash on health?Įffects of ash on health may be divided into several categories: respiratory effects, eye symptoms, skin irritation and indirect effects. Medical services can expect an increase in the number of patients with respiratory and eye symptoms during and after an ashfall event (see IVHHN guidelines on advice to the medical community). However, ashfalls can affect very wide areas around volcanoes and may cause major disruption to normal living. People can be more fearful of the health hazards of volcanic ash and gases than of the risk of dying from more major hazards, such as pyroclastic flows. In most eruptions, volcanic ash causes relatively few health problems, but generates much anxiety. Acidic ash can also damage vegetation, leading to crop failure. This acid coating is rapidly removed by rain, which may then pollute local water supplies. This beneficial effect of volcanism outweighs, over time, the hazards from infrequent eruptions, so fertile volcanic areas are often densely populated.įreshly fallen ash particles can have acid coatings which may cause irritation to the lungs and eyes. The fertility of the soils around many volcanoes is due to old ash deposits. Large ash deposits can incorporate into existing soils and become the future topsoil of a volcanic region. Airborne ash blocks out sunlight, reducing visibility and sometimes causes complete darkness during day light.Įruptions can also generate thunder and lightning from friction between the fine, airborne particles which can be localised above the volcano or accompany large ash plumes as they move downwind. Thus, it can range in colour from light grey to black and can vary in size from being like grit to being as fine as talcum powder.
Ash varies in appearance depending upon the type of volcano and the form of the eruption. It is formed during volcanic explosions, from avalanches of hot rock that flow down the side of volcanoes, or from red-hot liquid lava spray. Volcanic ash is often hot very close to the volcano but is cool when it falls at greater distances. Volcanic ash is composed of fine particles of fragmented volcanic rock (less than 2 mm diameter). What to do to protect yourself against ash.What factors affect repriratory systems?.Why are people with chronic lung problems at special risk?.
#Projectile effects are a hazard in how to
This guide explains the potential health effects of volcanic ash and gives details on how to protect yourself and your family in the event of a volcanic ashfall.Ī printable version of this guide can be found at Contents This document has been prepared by the International Volcanic Health Hazard Network (IVHHN), Cities and Volcanoes Commission, GNS Science and the United States Geological Survey (USGS) to promote the safety of those who experience volcanic ashfall.
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