The Poás Volcano, located at an elevation of 2,687 meters above sea level in Costa Rica, has been experiencing persistent eruptions since March 23, which have led to the indefinite closure of the Poás National Park to protect officials and visitors.

The ongoing emissions of gases and ash pose potential health risks to local residents and those living in surrounding areas, prompting the Ministry of Health to issue recommendations.

Geoffroy Avard, a volcanologist from the Volcanological and Seismological Observatory of Costa Rica (Ovsicori), reported on Tuesday that the volcano remains highly active.

He noted changes in the seismic signals observed at the site, whereby the previous overlapping acoustic signals of continuous tremors and explosions have shifted to more fragmented activity, characterized by tremors that are now less frequent alongside ongoing explosions.

As of Thursday, Ovsicori updated the public on the situation, indicating the continuation of phreatic eruptions—consisting of steam and water at high temperatures—and a persistent release of ash.

Estimates suggest that the Poás Volcano is emitting up to 600 tons of sulfur dioxide (SO2) daily, a colorless gas with a strong, irritating odor reminiscent of rotten eggs, noticeable in communities such as Grecia, Chilamate, Alajuela, Carrillos de Poás, and San Isidro de Alajuela.

Sulfur dioxide is released during volcanic eruptions and is also a byproduct of fossil fuel combustion.

Its presence in the atmosphere is accompanied by health risks, while volcanic ash, which is abrasive, can adversely affect both human and animal health and damage crops.

In light of these conditions, the Ministry of Health has alerted the nearby population to be vigilant for symptoms that may include nasal congestion, coughing, breathing difficulties, throat pain or irritation, redness and burning of the eyes or conjunctivitis, skin irritation or itching, and gastrointestinal issues.

Individuals exhibiting such symptoms are advised to seek medical attention.

To mitigate exposure, it is recommended that individuals refrain from unnecessary contact with ash and gases.

For those living or working in affected areas, the use of surgical masks or face coverings is advised.

Alternatively, a damp cloth mask may provide temporary protection.

Additionally, residents are encouraged to close windows and doors, place damp cloths at door thresholds and air intake points, and moisten ash before cleaning to minimize dust dispersal.

Due to the indefinite closure of the National Park, tourists who have purchased tickets are required to either reschedule their visit or request a refund.

Instructions for refunds can be obtained by contacting the email address poas.info@sinac.go.cr.