San José, Costa Rica, since 1956
Public Health

Volcanic ash from Turrialba contributes to air pollution in metro area

Volcanologists believe Turrialba Volcano isn’t going to stop erupting any time soon and that could have long-term health effects for people living downwind.

Experts from the Health Ministry and the National University said fine particulate matter from volcanic ash and automobile exhaust is a major public health concern in the Greater Metropolitan Area (GAM), which includes San José and parts of Alajuela, Cartago and Heredia. The area is home to 60 percent of Costa Rica’s population, 70 percent of its vehicle fleet and 85 percent of its industry, according to the National Statistics and Census Institute.

Jorge Herrera, an environmental analyst with the National University, told The Tico Times that Costa Rica does not have elevated levels of large particulate pollution but “where we’re having problems is with the smallest particles.”

Herrera said most volcanic ash is too large to enter someone’s lungs but some is small enough to be considered fine particulate matter — smaller than 2.5 micrometers in diameter — and has the potential to enter the lungs and the bloodstream.

The health risks for super fine ash are higher than for other air pollutants, he said, because ash is acidic and can contain high levels of heavy metals, like nickel, which is carcinogenic. Fine particle pollution can also cause or aggravate cardiovascular and pulmonary problems, according to a new report from the National University that looks at air quality in the GAM between 2013 and 2015.

The average annual amount of fine particle pollution in the GAM ranged between 22 and 25 micrograms per cubic meter (μg/m³) during the last three years, more than double the recommended level set by the World Health Organization. Nevertheless, researchers found no significant increase in pollution during the study period.

Ash blowing in frequently from Turrialba is a recent addition to the metro area’s mélange of air pollution but vehicle exhaust and industry emissions have long been the dominant sources of nitrogen dioxide and other pollutants. Many sites in San José meet Costa Rica’s national guidelines for nitrogen dioxide levels (100 μg/m³) but not the 40 μg/m³ established by the World Health Organization.

Testing sites around the Metropolitan Cathedral showed average levels ranging between 50 and 56 μg/m³ from 2013 to 2015. The air in front of San Juan de Dios Hospital had the highest concentration of nitrogen dioxide, ranging from 63 to 65 μg/m³ over the last three years.

The Health Ministry will soon be equipped for the first time to give the public real-time information to avoid the worst health impacts from air pollution. The ministry has invested ₡400 million (roughly $750,000) in a mobile air quality laboratory. Residents will be able to check the day’s air quality online and see recommendations for at-risk groups, including young children, the elderly or others with respiratory conditions like asthma or bronchitis.

The government is working on several initiatives aimed at curbing air pollution, including charging vehicle-owners an annual fee based on the vehicle’s emissions.

Herrera said Costa Rica also needs to improve fuel quality and provide real public transportation options to cut down on individual car use.

Related: San José’s air among cleanest of Latin American cities

Contact Zach Dyer at zdyer@ticotimes.net

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