Why The EPA Wants Data From Pittsburgh Rooftops

Feb 6, 2017

Scientists from Carnegie Mellon University have been climbing onto local rooftops and installing air quality monitors. It’s a project of CMU’s Center for Air, Climate and Energy Solutions, funded in part by the Environmental Protection Agency. Similar centers were also set up at Harvard and Yale.

90.5 WESA’s Liz Reid spoke with professor Albert Presto about the project, which aims to illuminate how things like traffic patterns and business density impact air quality. Data gathered in Pittsburgh will be contrasted with cities in Texas and California.

On why researchers are looking to compare data from different cities:

CMU postdoc Naomi Zimmerman and professor Albert Presto install an air quality monitor on the roof of the Community Broadcast Center on Wednesday, January 18, 2017.
Credit Liz Reid / 90.5 WESA

"In the past, people have done these sort of pollutant mapping studies on a city by city basis, and so there's a study for New York and a study for Chicago. We've actually done work like this in Pittsburgh before. But then what happens is the results are really limited to that city and people will build models to describe the spatial variation, but they only work in that city. What we want to do is move toward something that's more general. For example, it would be great to predict what Indianapolis looks like without having to go there and do a year's worth of measurements."

On how this project is different than existing air quality monitoring efforts in the region:

"Every city has monitors that are set up to check compliance with the Clean Air Act. And mostly those monitoring networks sample what we would call urban background locations, so sort of like in an urban park or in or near specific industrial sources. And what we really want to do is get finer scale information. So whereas there are something like seven or ten monitoring stations that are for EPA compliance in the whole county, we're taking 10 monitoring stations and squashing them all into Downtown.

So what we did before was what we called a transect. The wind here typically goes from west to east or southwest to northeast, and so we basically drew a line starting in South Fayette and then followed that Southwest to northeast trajectory and laid out our 10 samplers between South Fayette and Fox Chapel."

An air quality monitor installed on the roof of the Community Broadcast Center on Wednesday, January 18, 2017.
Credit Liz Reid

On how things like topography and businesses impact air quality:

"It really matters sometimes, specifically where you are. So for instance, one of our samplers during the transect was at the zoo and overnight at the zoo particulate matter concentrations were higher than our monitor in the Hill District or in Lawrenceville or in South Fayette. And we think that had to do with the fact that it's sort of down in the valley and you can get these inversions that sort of cover the river valleys. Air can get trapped near the ground at night, and it seems like in that particular area you know polluted air got trapped at night, more so than it did in the other spots.

The other sort of interesting thing we found so far are these hotspots caused by restaurants. So in addition to these stationary monitors that we're setting up, we're doing a lot of mobile sampling, and we kept seeing these big spikes in our mobile sampling. And it turns out the vast majority of these spikes that we're seeing are when we drive by restaurants."

On why this data is important to the EPA:

The EPA funds a series of what they call centers and they do these on something like a five year timescale. And the idea is that we'll produce research that is policy-relevant, that will help EPA make their next set of policies going forward. So we know that there are really fine scale variations in air pollution from one street to the next or from one neighborhood to the next, and it seems like the direction the regulations are going is to minimize people's exposures in the places they are, rather than just to sort of try and get an urban background location in each city down below some standard."

On what a Trump administration EPA might do with this data:

"I think the short answer to what's happening in the near-term is none of us know, and it's not necessarily clear that people at the EPA know. Regardless, I think whatever we produce whatever we learn you know we'll publish it. It will still exist. If it gets ignored now maybe five years down the line, someone else will will read it and think it's important enough to implement policy." 

This interview has been edited for length and clarity.