Wind and Air Pollution Forecast in Quito

Posted on June 8th 2015

Guagua Pichincha volcano in Ecuador (Attribution)

Beijing citizens do know for long that the best natural way to clean the pollution in the air is strong winds from the North, while winds from the south might, on the contrary, bring more pollution from Hebei.

In Quito, Ecuador, there is a similar problematic, except that the pollution comes from the active volcanos. Fortunately, they do not erupt that often, but when they erupt, better avoid being under the the heavy ash cloud formed by the explosive eruptions (see picture).

It is actually the Air Quality team from Quito Ambiente, with whom we have been recently cooperating, that indicidated us that the 4 volcanos with most concerns are Cotopaxi, Reventador, Guagua Pichincha and Tungurahua. Although the volcanoes are not so near from Quito, Guagua Pichincha and Reventador did recently cover Quito with ashes. Ancient reports also show that last time Cotopaxi erupted, Quito got covered with a cloud of ash which stayed for a whole week!


Considering that the wind forecast which is already availalbe for Quito, and that each time volcano are errupting an alert is sent to the Quito Ambiente team, the obvious question is wether it is possible to predict the direction the ash cloud will take, and more importantly, whether the 1.5 million citizen living in Quito would be at risk (in which case, the Quito Ambiente would send preventive alerts).

Wind forward trajectories
(attribution: Nanjing university)

The map below is showing the 8 days forecast for both Wind Direction and Speed (in m/s) at 250mb (approx 10KM) for the 4 above mentioned volcanos. The wind forecast data is based on the latest GFS 0.25° data, which is udpated every 6 hours, and has a 3 hours interval. The horizontal and vertical lines in blue are showing the 0.25° grid, so any point between the grid is calculated as the interpolation of the 4 corners.

The wind path are showing the forward trajectory for the next 8 hours (with a 10 minute precision). Each point on the trajectory is computed using the wind data from the point own location instead of the source location (as it was done in the first version of this article). Moreover, since the GFS is only available with a 3 hours resolution, any data between two 3 hours point is linearilly interpolated.

This is of course far enough from being perfect, but this is already a good indication in case of volcano erruption. We will of course continue optimizing the wind model used in this map. One obvious improvement is to take into account the wind vertical speed (as shown on the bottom part of the graph on the right), since, when changing altitude, the wind also changes direction (in the current simulation, constant altitude is assumed).


All the dates below are in UTC (GMT+0)
Ash Cloud Forecast map -- loading...

Wind trajectory colors:


Isobaric level 100mb: ~15KM.
Isobaric level 250mb: ~10KM.
Isobaric level 550mb: ~5KM.

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    指数大気質指数の分類(米国)健康影響 / カテゴリ粒子状物質(PM10,PM2.5)
    0 - 50良い - Good通常の活動が可能なし
    51 -100並 - Moderate特に敏感な者は、長時間又は激しい屋外活動の減少を検討非常に敏感な人は、長時間または激しい活動を減らすよう検討する必要がある。
    101-150敏感なグループにとっては健康に良くない - Unhealthy for Sensitive Groups心臓・肺疾患患者、高齢者及び子供は、長時間又は激しい屋外活動を減少心疾患や肺疾患を持つ人、高齢者、子供は、長時間または激しい活動を減らす必要がある。
    151-200健康に良くない - Unhealthy上記の者は、長時間又は激しい屋外活動を中止
    201-300極めて健康に良くない - Very Unhealthy上記の者は、すべての屋外活動を中止
    300+危険 - Hazardous上記の者は、屋内に留まり、体力消耗を避ける
    (Reference: see wikipedia,and


    北京の医者Richard Saint Cyrの非常に便利な健康アドバイスについては、 をチェックしてください。

    Usage Notice: All the Air Quality data are unvalidated at the time of publication, and due to quality assurance these data may be amended, without notice, at any time. The World Air Quality Index project has exercised all reasonable skill and care in compiling the contents of this information and under no circumstances will the World Air Quality Index project team or its agents be liable in contract, tort or otherwise for any loss, injury or damage arising directly or indirectly from the supply of this data.



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