🎈 Public Lab: lightweight air quality sensors for a weather balloon

Question: lightweight air quality sensors for a weather balloon

by glenc | October 12, 2016 20:33 | #13556

I would like to put a particulate matter, CO2, humidity, or nitrogen oxides data collection device onto a weather balloon. Do you know where I may find such sensors? It should log the data onto an SD card, which I would retrieve after the balloon pops. There is already GPS, temp and pressure sensing on board, as part of the balloon kit.

I teach one class at Woodbury University this semester: intro environmental science for non-majors. The school gave me $700 to get a weather balloon kit, and I am collaborating with a local high school teacher to launch the balloon. The kit only records temp, pressure, and altitude. I want to gather more data, such as CO2, humidity, NOx, PM2.5, or any PM. But I do not know if it is possible to collect such data on a weather balloon because the weight including battery must be very limited.

Thank you.

2 Comments

Not to take credit for these answers, but I saw a couple great responses (one from @gretchengehrke, ) from this thread on which you originally asked, and wanted to just be sure they're linked-to from here: https://groups.google.com/forum/#!topic/plots-airquality/0gn3lm9wUFc

Wig:

Just a small point Glen, which you may already know since you have thought to include meteorology on board, but the biggest driver of many regional air pollution levels tends to be the atmospheric boundary layer, with traps also an issue. The boundary layer is generally low in morning and during temperature inversions. With the turbulence created by solar warming, post sunrise, the boundary layer tends to rise rapidly during the day, expending the total area in which pollutants may be dispersed and thereby decreasing effective density. Of course, photochemical action also helps create new secondary PM2.5 as organics get oxidized and denser, increasing partitioning to PM, midday or a little later. Since this takes time it can be considerably downwind of the sources. This plus geographic traps, like mountains, is basically an important reason why San Bernardino Riverside is so polluted to the east of LA. Again, you may already know all of this but perhaps some on the list do not.

@gretchen:

What Wig says is absolutely right, and some of the most tragic and deadly air quality events have been during temperature inversions when pollution has been socked in cities (like the London fog episode in the early 1950s). It might actually be a very meaningful and memorable experience for your students to observe how particulate matter decreases above the boundary layer (which, depending on where are, is often ~ 1000 m during the day, so might be doable with a balloon kit).

Another factor to consider is how humidity changes with altitude. Most (all?) real-time or near-real-time particulate matter monitors use an optical system to count particles. Basically, they shine a light into a chamber and measure the light refracted, assuming it is due to particles. This makes these systems very sensitive to humidity though, as water drops will also refract the light. I'm really not sure how much this would impact measurements, but since absolute humidity decreases with altitude, you might get a more accurate particle count at higher altitudes. Anyway, it's just something to think about.

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