Community monitoring projects near petrochemical facilities around Beaver, PA

Community members have been deploying PurpleAir monitors along the Ohio River Valley with a particular emphasis on the Shell ethane cracker/petrochemical facility near Beaver, PA. Significant amounts of particulate and VOC emissions are expected when the facility begins production, currently planned for late 2022. There are a variety of organizations working to deploy monitors in the region with different funding streams, but many of us collaborate to find suitable monitor hosts and share information. One of the projects that I’m working on is plainly labeled the “Community Monitoring Project” and is set up to deploy monitors to 20 sites around Shell, measuring particle and VOC levels at each site. The Shell facility is being built right where 376 meets the Ohio River.

Here is a map of the monitors showing particle levels:

And here is a map showing VOC levels (calibration is not well-established at this time, but valuable information can still be gathered from the data):

Of the PurpleAir monitors on these maps, only the ones with labels beginning in “CMP” are specifically part of my project, but that’s the beauty of the PurpleAir network – other groups can put up their own monitors and we all benefit! Many of the monitors further up the Ohio River were deployed by Communities First, Sewickley. . Another group, BCMAC, has been supportive of monitoring efforts and has also launched a community “watchdog” group and website: .

I am also working with the Environmental Health Project to generate reports from the data to show patterns in pollution levels before and after start-up.

Feel free to comment here to discuss the project, other nearby projects, or feel free reach out to me directly/privately.

Always Monitoring,
Mark Dixon

P.S. This project (focusing on the 20 monitor sites around Shell) is funded by the Direct Support Fund. The Direct Support Fund is made possible by The Heinz Endowments and The 11th Hour Project and is a project of the Mountain Watershed Association. For more information or to apply please visit w​​.


Thank you for sharing. It is especially valuable that you are getting sensors up before plant starts production?

I know the VOC sensors are not finished yet - but can you share any experience with regard to wood burning? Can you see pollution from stoves in VOC levels?

Your signiture ‘Always Monitoring’ is great :grinning:

Hmmm. I don’t have a lot of experience with wood burning and VOC monitoring, but it does appear that wood smoke has VOC’s in it: The Chemical Composition of Wood Smoke. I’d recommend exploring the topic with indoor and outdoor monitors. I think you will probably see a difference in the monitor data between wood smoke that is coming from a nearby house vs. wood smoke gathering broadly across a region. I find that super-local sources create more of a spiky signal in the pollution readings. Broader pollution creates a smoother signal as it rises and falls. I also see more pollution at night during inversion conditions. Do you have weather inversions where you are?

Still Always Monitoring,

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Thanks for sharing your project, Mark. This is great work!

I’ve been playing with the VOC data from the new BME680 board as well, and have encouraged others in our community (Louisville, CO) to add that functionality to their PurpleAir sensors as well. We experienced a major wildfire/urban conflagration in December-January which burned almost 1000 homes. Since then, our sensor network in the community has grown rapidly as people are concerned about AQ. We’ve gone from one or two sensors about a year and a half ago (when I deployed mine) to over 35 now. And in our local area, we are now up to about 14 VOC capable monitors.

I have noticed the same as you, that the VOC readings spike due to very local sources. Are yeah, though the output isn’t calibrated to a known scale yet (like ppm or mg/m^3), I’m encouraging folks to think of the data as still very valuable, though relative in nature. We are interested to see how the readings track as things dry out (the ground is snow covered now) and as cleanup of burned properties begins.

I’ll be interested in reading about your long-term monitoring project!

Thanks for sharing about your efforts, Bud! Sounds very interesting. I’d be really curious to see how VOC levels (and particle levels) change due to property clean-up after a major fire. There is a lot of work in remediation and demolition of lead-contaminated homes that might be relevant to you and others in the area as they seek to minimize the spread of contaminants in dust. Here’s a link to a program in Pittsburgh focused on that: . I’d imagine that keeping a site moist might help reduce hazardous dust, but I’m not an expert on that, I would also caution anybody looking at comparisons between the two situations in case there are other phenomenon at play that might actually make the air pollution situation worse. Local and federal experts can hopefully support the clean-up efforts with better information. Keep monitoring! And stay in touch!

Always Monitoring,

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Thanks, Mark! Yes, the county is starting to hydro-mulch burned properties now to keep the PM and ash down. But it will be really interesting to see how things go once removal begins. It is supposed to start March 1 and target completion is June 1. Hopefully our spring won’t be too dry. However, we only get about 12-14" of moisture annually in this area.

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I realized I forgot to answer Mark’s question about inversions. Yes- we have strong inversions in the Denver-Boulder area, and quite often during winter. A cold front came through last night and today we’re getting some snow. It is currently 28°F at the surface but about 50°F at 500m above ground level. So we have some cold, stable air in place today.

And here are our current VOC measurements in the area. Definitely elevated compared to a day with some mixing.

Thanks for sharing the map! I did a little comparison of the PurpleAir monitors in your area vs where I live in Pittsburgh. And while I don’t want to get into a debate over who has worse air quality (every region and situation is unique and worth addressing in its own way), I was fascinated to find that the VOC levels at my house in Pittsburgh, PA were much higher than the CO levels during our respective nighttime inversions – at least this week. I wonder if that is a regional weather or pollution source effect? Hmmm. I also had been under the impression that the PurpleAir monitors weren’t really well calibrated when it came to VOC’s (i.e. reading too high), but your VOC levels are much more reasonable looking than ours on the PurpleAir color spectrum. Fascinating. In the image below, “CMP1 Test” is at my house in Pittsburgh. The rest are in your area.
Screen Shot 2022-02-17 at 5.04.42 PM

It’s worth noting that on the morning of Feb. 16 (showing the VERY high VOC spike) we had a particularly stinky morning, with over 100 smell complaints showing up on this SmellPGH map: Smell Pittsburgh

And a plume visualization (animated at the link): Plume Pittsburgh

I can attest that it was an awfully stinky morning. Industrial stench wafted into my house and I woke up with a headache. :frowning:


Wow. Yeah we have no point source like that nearby. We do have a set of refineries about 20 miles away to the SE, but prevailing winds always keep that away from our area. Our VOCs are really local, and might be due to the fire debris at the moment. But nothing like what you are seeing in your area.

And you are correct- these VOC readings are not calibrated to a common scale, so they are only interpretable as relative readings at the moment.

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