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Costa Rica · Air quality

Air quality in Costa Rica: where to check and what to do

Costa Rica's ICCA index runs from 0 to 100 in five levels. IMN posts a weekly ICCA and Saharan dust forecast; Phaenyx found no real-time public map.

Updated 2026-10-27· 8 official sources· Leer en español

Short answer. Costa Rica's official air quality index, the ICCA, runs from 0 to 100 in five levels, from "good" to "hazardous" 1. The National Meteorological Institute (IMN) publishes a weekly ICCA forecast with a Saharan dust outlook 23. Phaenyx found no public real-time air quality map: the health ministry says the index is not yet in everyday use for lack of monitoring resources 4.

Where can I check air quality right now?

Start with the IMN's Pronóstico Calidad Aire page, which links to the weekly air quality forecast 2. The weekly forecast, a PDF replaced each week at the same address, gives an hourly ICCA forecast for the next 7 days, the daily maximum, and a Saharan dust forecast 3. Open it for the current week. The IMN also publishes a monthly air quality bulletin on PM2.5, PM10, NO2, SO2, CO and ozone measured by monitoring stations 5.

The regulation says the Ministry of Health will publish real-time data from the national network's automatic stations, with the ICCA 1. Phaenyx found no such public page. The ministry's 2023-2024 report says the index has not been put into practice for lack of resources for the monitoring network, and is still unknown to the public 4.

What do the index levels mean?

Decree 39951-S sets the Índice Costarricense de Calidad del Aire (ICCA); the worst pollutant sets the value 1. The regulation tells the Ministry of Health to recommend preventive actions at each level 1:

ICCA Colour Level Examples of preventive action 1
0-20 Green Buena (good) None
21-40 Yellow Unfavourable for sensitive groups Active children and adults and people with respiratory disease such as asthma should consider limiting prolonged outdoor effort (ozone)
41-60 Orange Desfavorable (unfavourable) The same groups should avoid prolonged outdoor effort, especially children (ozone)
61-80 Red Muy desfavorable (very unfavourable) People with respiratory disease such as asthma should avoid any outdoor activity; everyone else, especially older people and children, should reduce outdoor effort (PM10)
81-100 Purple Peligrosa (hazardous) Everyone should avoid outdoor effort (ozone); everyone should avoid any outdoor effort (PM10)

People with heart disease such as angina are also told to reduce effort and avoid sources of carbon monoxide such as heavy traffic 1. See Air quality index explained.

How polluted is the air on average?

The population-weighted median of Costa Rican cities shows about 18 µg/m³ of PM2.5 (annual mean 2021-2023) 6, more than three times the WHO guideline of 5 µg/m³ 8. The Ministry of Health's own stations in the Greater Metropolitan Area averaged 12 µg/m³ in 2023 and 12.6 µg/m³ in 2024 4. Nitrogen dioxide is about 7 µg/m³ 7, below the WHO guideline of 10 µg/m³ 8. That NO2 figure is a regional background over roughly 80 km: a busy street will be higher.

What should I do on a bad air day, during dust or volcanic gas?

Follow the ICCA actions above. At its monitoring stations, the ministry's report found that daily PM2.5 peaks came in the dry season, especially April to June, linked to weather, biomass burning and dust 4. During a 2024 campaign at Poás, sulphur dioxide and fine particle peaks linked to the volcano exceeded the regulated values 4.

Phaenyx found no official Costa Rican guidance specific to Saharan dust, smoke or volcanic gas. See Dust storms, Volcanic ash, Wildfire smoke, A clean-air room at home, Masks for smoke, Sensitive people and polluted air and Children and polluted air. A household plan can note who at home is sensitive to polluted air.

Frequently asked questions

Is there a live air quality map for Costa Rica?

Phaenyx found none. The IMN publishes a weekly ICCA forecast 23.

What is a "good" ICCA value?

0 to 20, shown in green 1.

Does the IMN forecast Saharan dust?

Yes. The weekly forecast includes a Saharan dust outlook 3.

When is the air usually worst?

In the dry season, especially April to June, according to the health ministry's 2023-2024 report 4.

Sources

  1. Poder Ejecutivo (copy hosted by the Instituto Meteorológico Nacional, IMN) — Reglamento de Calidad del Aire para Contaminantes Criterio, Decreto Ejecutivo N.º 39951-S — https://www.imn.ac.cr/documents/10179/48135/Reglamento+calidad+del+aire/2eb9d17f-1e08-429e-81c5-7d5255800afa (accessed 2026-10-27; articles 12 to 14)
  2. Instituto Meteorológico Nacional (IMN) — Pronóstico Calidad Aire — https://www.imn.ac.cr/web/imn/pronostico-calidad-aire (accessed 2026-10-27)
  3. Instituto Meteorológico Nacional (IMN) — Pronóstico semanal de calidad del aire (weekly PDF) — https://www.imn.ac.cr/documents/10179/48135/Pron%C3%B3stico+Calidad+Aire/724d3873-489c-45e8-bed6-5225c68e730f (accessed 2026-10-27; the file at this address is replaced each week)
  4. Ministerio de Salud de Costa Rica, with the Universidad Nacional — IX Informe de Calidad del Aire, Gran Área Metropolitana de Costa Rica 2023-2024 — https://www.ministeriodesalud.go.cr/index.php/biblioteca-de-archivos-left/documentos-ministerio-de-salud/material-informativo/material-de-comunicacion/calidad-del-aire/informes-4/10321-informe-calidad-aire-2023-2024/file (accessed 2026-10-27; posted 11 May 2026)
  5. Instituto Meteorológico Nacional (IMN) — Boletín Calidad Aire — https://www.imn.ac.cr/web/imn/boletin-calidad-aire (accessed 2026-10-27)
  6. Atmospheric Composition Analysis Group (ACAG), Washington University in St. Louis — Surface PM2.5, V6.GL.02.04 (annual mean 2021-2023) — https://sites.wustl.edu/acag/datasets/surface-pm2-5/ (accessed 2026-10-27)
  7. Copernicus Atmosphere Monitoring Service (CAMS) — CAMS global reanalysis (EAC4) — https://ads.atmosphere.copernicus.eu/ (accessed 2026-10-27)
  8. World Health Organization (WHO) — WHO global air quality guidelines (2021) — https://www.who.int/publications/i/item/9789240034228 (accessed 2026-10-27)

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Sources

  1. Poder Ejecutivo (copy hosted by the Instituto Meteorológico Nacional, IMN) · Reglamento de Calidad del Aire para Contaminantes Criterio, Decreto Ejecutivo N.º 39951-S checked 2026-10-27
  2. Instituto Meteorológico Nacional (IMN) · Pronóstico Calidad Aire checked 2026-10-27
  3. Instituto Meteorológico Nacional (IMN) · Pronóstico semanal de calidad del aire (weekly PDF) checked 2026-10-27
  4. Ministerio de Salud de Costa Rica, with the Universidad Nacional · IX Informe de Calidad del Aire, Gran Área Metropolitana de Costa Rica 2023-2024 checked 2026-10-27
  5. Instituto Meteorológico Nacional (IMN) · Boletín Calidad Aire checked 2026-10-27
  6. Atmospheric Composition Analysis Group (ACAG), Washington University in St. Louis · Surface PM2.5, V6.GL.02.04 (annual mean 2021-2023) checked 2026-10-27
  7. Copernicus Atmosphere Monitoring Service (CAMS) · CAMS global reanalysis (EAC4) checked 2026-10-27
  8. World Health Organization (WHO) · WHO global air quality guidelines (2021) checked 2026-10-27