Pleasures, St. Eustatius Air Quality

Lat 17.48N Long 62.97W Elevation 575 ft (175m)

The Pleasures weather station includes two air quality monitors and a geiger counter: a Dylos DC1100-Pro monitor, an AlphaSense OPC-N3 monitor, and a Magnii Technologies RAD121 geiger counter.

The Dylos measures and counts particles / cubic foot larger than 0.5 micrometer in diameter. The AlphaSense OPC-N3 measures particles larger than 0.38 micrometer and collects the counts into bins by particle size which allows us to determine the approximate mass of the particles and calculate the Air Quality Index. The RAD121 geiger counter measures radiation in counts per minute. The tube has a sensitivity of 450 CPM/mR/HR.

This page shows the data from the AlphaSense monitor with the exception of two charts: one with the scale of Excellent to Very Poor which is from the Dylos monitor and one showing the counts per minute of radiation.

We keep the Dylos data for comparison to historical data which we have since Jan 2013. We installed the AlphaSense in Dec 2018. We installed the RAD121 in Oct 2019.

For more information, see these articles from Wikipedia on Particulate Matter and Air Quality Index.

Latest Observation

Valid: 15-Aug-2020 2:43:57am

Air Quality Index

Air Quality Index (AQI) is the higher of the AQIs calculated using the 1 hour average of PM2.5 and PM10.
Current AQI=57.1 (Moderate)
Today's High=57.10 @ 02:43
Today's Low=34.40 @ 00:33

count kp/m³6039
count kp/f³171
device µg/m³1.64
1 hr avg µg/m³1.60
count kp/m³9019
count kp/f³255
device µg/m³14.45
1 hr avg µg/m³12.89
count kp/m³9437
count kp/f³267
device µg/m³63.98
1 hr avg µg/m³66.50
Air Quality 48-hr Chart Air Quality 30-day Chart

Radiation Counts

Radiation count/min Chart Missing

Particle Counts and Mass Over Time

ASPm1kpf3Chart ASPm1ugm3Chart ASPm2p5kpf3Chart ASPm2p5ugm3Chart ASPm10kpf3Chart ASPm10ugm3Chart

1 Hour Averages

AvgASPm2p5ugm3Chart AvgASPm10ugm3Chart
*** - shows the 1hour average mass

Latest AlphaSense Histograms for Particle Counts and Mass

The following charts are for the latest sample only.

ASHistogramCount2dChart ASHistogramMass2dChart

The following charts are for the 1 hour average.

AvgASHistogramCount2dChart AvgASHistogramMass2dChart

AlphaSense 3d Histograms for Particle Counts and Mass

These 3D charts show the particles in Pleasures air for the past two days averaged for each hour. Although most particles are small, larger particles have much more mass and so contribute more to the Air Quality Index (AQI). Particles larger than about 18µm are too heavy to drift across the Atlantic as Sahara Dust. These are local dust and pollen blown up by wind gusts on Statia. The first chart shows particle counts in thousands of particles per m³. The second chart show masses in µg/m³. The particles are summed into one of 24 bins that vary by particle size. The x-axis is ordered by particle diameter in µm for the 24 bins. The y-axis shows each hour for the last 48 hours.

AvgASHistogramCount3dChart AvgASHistogramMass3dChart


This weather information is derived from usually reliable government and private sources but it is not an official government product. Monitor your local radio station for storm watches and warnings issued by local authorities. We do our best to provide accurate information as a free public service, but we assume no liability for errors.