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Formación de nuevas partículas a partir del isopreno en condiciones de la troposfera superior
Jiali Shen1,2, Douglas M Russell3, Jenna DeVivo4
1Institute for Atmospheric and Earth System Research/Physics, Faculty of Science, University of Helsinki, Helsinki, Finland.
Nature
|December 5, 2024
Resumen
La formación de nuevas partículas en la troposfera superior tropical es impulsada por moléculas orgánicas oxigenadas con isopreno (IP-OOM). Estas moléculas se nuclean y crecen rápidamente, incluso con bajas concentraciones de ácido sulfúrico, formando nuevas partículas atmosféricas.
Área de la Ciencia:
- Química de la atmósfera
- Ciencia de los aerosoles
- Ciencias del clima
Sus antecedentes:
- Formación ubicua de nuevas partículas (NPF) observada en la troposfera superior tropical.
- Se detectaron altas concentraciones nocturnas de isopreno en esta región, pero no se conocían los vapores precursores.
- El isopreno es un compuesto orgánico volátil biogénico emitido por las selvas tropicales.
Objetivo del estudio:
- Investigar el papel del isopreno en la formación de nuevas partículas en la troposfera superior.
- Determinar los mecanismos de nucleación y crecimiento de las partículas derivadas del isopreno.
- Evaluar la influencia de las condiciones atmosféricas como la temperatura, el ácido sulfúrico y el NOx en el NPF.
Principales métodos:
- Experimentos de laboratorio realizados en la cámara CLOUD del CERN.
- Condiciones de la troposfera superior simuladas: temperaturas de -30°C y -50°C.
- Reacciones investigadas de radicales hidroxilo con isopreno y posterior nucleación/crecimiento de moléculas orgánicas oxigenadas con isopreno (IP-OOM).
Principales resultados:
- NPF confirmado iniciado por reacciones de radicales hidroxilo con isopreno a temperaturas superiores de la troposfera.
- Moléculas orgánicas oxigenadas con isopreno (IP-OOM) nucleadas en las concentraciones superiores de la troposfera observadas sin vapores adicionales.
- Las tasas de nucleación fueron significativamente mejoradas por el ácido sulfúrico o los oxoácidos de yodo, alcanzando hasta 30 cm-3s-1.
- IP-OOM facilitó el crecimiento rápido de las partículas (3-60 nm h-1).
- El NPF y el crecimiento persistieron en presencia de concentraciones superiores de NOx en la troposfera.
Conclusiones:
- Las emisiones de isopreno de las selvas tropicales pueden impulsar la formación de nuevas partículas significativas en la troposfera superior tropical.
- Las moléculas orgánicas oxigenadas con isopreno son precursores clave del NPF en esta región.
- Los resultados sugieren una contribución sustancial del isopreno a la carga de aerosoles y sus posibles implicaciones climáticas.
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