Second of two stories on EPA air pollution monitoring. Click here to read part one.
High school students toting pollution monitors the size of paperback books scoped out the future of environmental protection recently at a park in Brooklyn, N.Y.
Tim Dye, a senior vice president for Sonoma Technology, oversaw the monitoring tests conducted by six student teams whose equipment sniffed for airborne soot along Sunset Park's running trails, sidewalks and lawns.
"The day we were doing it, the east-west streets had a strong wind and there was a lot of dust being kicked up," Dye recalled in an interview. "When you weren't in the wind alley, the levels went down. When we collected all the data, there was a clear sawtooth pattern. By having the measurements and the individual experience, we could determine what was going on."
U.S. EPA -- which oversees the nation's most extensive network of air pollution monitors -- is looking to such small, mobile devices to fine-tune its picture of the air Americans breathe.
Chet Wayland, director of EPA's air quality assessment division, said falling prices for sensors have meant a "lot of really cool stuff" is now possible in air monitoring. It's possible, he said, the agency's 3,000-monitor network might evolve beyond stationary machines into something more personal.
"A fixed site monitor doesn't represent anyone's air," said George Allen, who coordinates the monitoring and assessment committee for Northeast States for Coordinated Air Use Management.
"What one person does is entirely different than what another person does," Allen said. "They're all these micro-environments that, taken together, can be a big network."
In an interview last fall, EPA enforcement and compliance chief Cynthia Giles described a potential "revolution ... in people's awareness about air pollution issues" that could come with personal monitors and vehicles that track air pollution (Greenwire, Oct. 23, 2013).
The first step, however, is a simpler change but one that analysts say could have major implications for tracking air pollution.
In its 2010 revisions of the National Ambient Air Quality Standards for nitrogen dioxide, EPA required that more than 100 cities install monitors near roads to measure NO2, with monitoring for particulate matter and other criteria pollutants to follow. The monitors are phased in depending on city size through 2017.
The goal is to track tailpipe pollution that isn't detected by stationary monitors that are usually placed far from major roads.
Although research has shown that traffic pollution can drift up to a mile, it's still most concentrated near roads, where researchers say it can linger and affect people who live and work near freeways.
Studies have shown that bicycle commuters and others near roads inhale more than the average share of soot and other exhaust pollutants. And a 2011 study published in the journal Epidemiology found that even bus riders and drivers were breathing in enough dust and nitrogen oxides that they performed worse on breathing tests than the bikers. There's been growing concern about the health effects of living or working near a busy roadway and breathing exhaust for hours on end.
Under the monitoring plan, the largest cities must place four monitors within 160 feet of roadways, while smaller cities will have to site one to three monitors. The mere act of doing the siting has proved challenging (see sidebar), but supporters say they hope the readings will provide valuable data that might influence city development.
Eric Stevenson, director of technical services at California's Bay Area Air Quality Management District, said the information can improve an already strong monitoring network. For example, he said, studies have shown that residents who live in buildings near roads show higher levels of asthma and other respiratory problems.
"We want to get in there and find out what's causing those health effects," Stevenson said. "Is it emissions? Is it socio-economic? We won't know until we have that data."
And that data can eventually be used to inform any number of decisions, like construction permits for apartment buildings, public parks and businesses.
"We've developed tools here at the district already to try to guide cities and counties on ways to infill so we're not building day care centers right next to a freeway," he said. "We work closely with our partners here ... with information sharing to hopefully minimize adverse impacts."
The National Association of Manufacturers, the U.S. Chamber of Commerce and other business groups challenged the particulate matter portion of the requirement in arguments last month before the U.S. Court of Appeals for the District of Columbia Circuit. The groups said the new readings would unfairly skew results and would lead to economic penalties that would hit businesses already affected by pollution-reduction plans.
The concerns do hark back to the broader question about the conflict between seeking out more data and avoiding attainment problems. But, said National Association of Clean Air Agencies President Bill Becker, more data drawn from more places will only help.
"Air pollution doesn't respect streets or regional boundaries, and we know that a small problem at one station probably exists at your office or across a river on a certain day," Becker said.
"But sweeping dirt under the rug doesn't make the room cleaner. It just hides it."
Monitoring gets personal
There's a small but growing movement to equip people with small, mobile pollution monitoring.
The more data, they say, the better for environmental protection.
Sonoma Technology's Dye, for example, often carries his hand-sized Air Beam device.
Tucked into a plastic case made by a 3-D printer, the Air Beam comprises off-the-shelf components: a microcontroller, a battery, a temperature and humidity sensor, a fan, and a particulate sensor. The monitor sends through Bluetooth real-time information on particulate pollution.
The Air Beam goes where Dye goes. He even held it out a taxi window in Beijing, where he found particulate matter readings on the outskirts of the city higher than in the busy city center (he later realized that was due to a ban on truck traffic inside the city).
"This device isn't going to let you go to a regulator and go to EPA and tell them there's a problem," Dye said. "But we know it's only going to get better."
As monitoring technology gets smaller and the cost of the technology also shrinks, buying a monitor isn't an expensive proposition.
Sensors have gone down to as little as $150, and although the technology is crude relative to the advanced EPA monitors, it's still enough to detect major trends, like pollution from traffic or nearby wood burning.
Even as EPA is exploring satellite technology and projections to spot air pollution trends, air assessment chief Wayland said the agency is well aware of personal monitoring enthusiasts and is considering how to incorporate personal data into future compliance and research discussions.
A draft Next Generation monitoring road map issued last March by the agency lays out plans to be "actively involved" in new technology and analyze what the advances mean for the future.
"The Weather Channel carries air quality. You pick up USA Today and it has information on air quality. People really want to know," Wayland said. "Some people think it's cool, some people need it for health reasons. People really just like to know what's going on around them."
The monitors can come in a variety of applications, from the hand-held AirCaster to larger ones that can sit in a kitchen or backyard. EPA has developed "mobile monitors" in cars rigged up with sensors and computers that can track pollutants and particulates along highways. The Pennsylvania-based nonprofit Group Against Smog and Pollution (GASP) has outfitted bicycles with monitors on the handlebars to create a map of Pittsburgh cycling routes.
EPA and the Department of Health and Human Services even awarded $100,000 to a Conscious Clothing system that would rig a soot monitor onto a wearable vest (Greenwire, June 6, 2013).
A pilot program run by EPA has installed a solar-powered low-cost monitor in a park bench in Durham, N.C., that broadcasts real-time ozone and particulate matter data through its Village Green pilot. The real-time readings -- able to be read on a computer or phone -- can track effects as detailed as a spike when a car drives by or a smoker lights up a cigarette on the bench.
The CitizenAir website -- which Dye helped create -- acts as a sounding board for personal air enthusiasts, where they can share recordings and new technology and discuss EPA's future strategies.
Impact seen on regulators, regulations
A model for EPA might be the National Weather Service, which collects meteorological data from more than 8,000 backyard stations through its Citizen Weather Observer Program and integrates them into an online database. A volunteer with the right equipment can apply for the program, which has given finer details to the service's network of stationary systems and satellites.
The open question, however, is how reliable any citizen air data will be for regulatory purposes, as a $150 sensor won't pick up the same degree of pollution or varied information as EPA-sanctioned permanent monitors. Just the intake on the large-scale monitors run by air agencies is bigger than most hand-held devices.
Stationary monitors feed their readings into computers that analyze and crunch data, factor in meteorological conditions, and can flag anomalous findings. Monitors will have backups that run less frequently but can confirm data and are checked annually by EPA and as much as weekly by the agencies that run them.
The technology that's available today can't claim nearly the same quality assurance, especially when it costs just $150. Readings can be thrown off by water moisture -- a concern on foggy days -- and can't be calibrated across multiple devices to ensure a consistent network. Even the most ardent supporters say that right now, the monitors are best used for spotting trends and drawing broad-stroke conclusions.
"Some of these devices are qualitative, some I would call semi-quantitative," Allen said. "None of them come even close to the demands and complexities of regulation."
Still, he added, citizen science is a growing field, and "empowering people to measure their own pollution" can yield pressure for cleanups.
Wayland agreed, adding that individual monitors also offer a good spot to test new technology.
"The technology is going to allow us to collect a lot more data in a lot more places," Wayland said. "But I'm also excited because if there's a new technology that develops and it pans out, then we ought to be able to apply it to our regulatory monitors down the road and bring down the cost."
Dick Valentinetti, a former Vermont regulator and chairman of the National Association of Clean Air Agencies' monitoring committee, said he could see public demand for individual monitoring persuading EPA to adopt more of it.
"Every monitor only gives you a snapshot," Valentinetti said. "Let's say instead of one monitor, you could get 60 snapshots of a small area. You could almost get rid of any anomalies. That's really going to make the future."
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