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What health hazards are posed by vog (volcanic smog)?

Vog poses a health hazard by aggravating preexisting respiratory ailments. Sulfur dioxide (SO2) gas can irritate skin and the tissues and mucous membranes of the eyes, nose, and throat, and can penetrate airways, producing respiratory distress in some individuals. Aerosol particles in vog can also penetrate deep into human lungs and, at elevated levels, can induce symptoms of asthma.

Physical complaints associated with vog exposure include headaches, breathing difficulties, increased susceptibility to respiratory ailments, watery eyes, sore throat, flu-like symptoms, and a general lack of energy.

Tiny droplets of sulfuric acid in vog creates acid rain, which can leach lead from roofing and plumbing materials, such as nails, paint, solder, and metal flashings. Leached lead poses a health hazard when it contaminates drinking water in rooftop rainwater-catchment systems.

The presence of vog reduces visibility, creating a potential hazard for drivers. Vog can also limit visibility for air and ocean traffic. 

Vog is a hazard that's associated with Hawaiian volcanoes in particular. 

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