Baltimore's air requires action

The Baltimore metro area ranks #6 worst in the US when it comes to number of days with elevated air pollution in 2016 (114 days with "code yellow"), significant parts of the metro area have been for years ozone non-attainment areas under the Clean Air Act. Live Strong placed Baltimore as the #5 worst city for air quality in 2017 (albeit, without providing sources). States submit their air quality

No large point source polluters are left in the former smokestack city of Baltimore
The incinerator is one of the few left

implementation plans (SIP) for certain pollutants at certain deadlines and cross their fingers that those plans get accepted, even though the target levels remain elusive. In the eyes of citizens, the matter of clean air has become complicated, cumbersome and obtuse with less pollution in plain sight. Consequently, if code yellow or code red are called out in the summer, hardly anybody bats an eye.  Hardly anybody knows what it means and nobody really changes their way of life or leaves the car in the driveway.

Ground-level ozone and airborne particles are the two pollutants that pose the greatest threat to human health in this country. Ozone, also known as smog, can irritate your respiratory system, causing coughing, irritation in your throat or a burning sensation in your airways. It can reduce lung function, so that you may have feelings of chest tightness, wheezing, or shortness of breath. Ozone can aggravate asthma and trigger asthma attacks. People at greater risk from ground-level ozone are people with lung diseases, such as asthma, older adults and children and adults who are active outdoors.
Particle pollution, also known as particulate matter, is composed of microscopic solids or liquid droplets that are so small that they can get deep into the lungs and cause serious health problems. When exposed to these small particles, people with heart or lung diseases and older adults are more at risk of hospital and emergency room visits or, in some cases, even death from heart or lung disease. Even if you are healthy, you may experience temporary symptoms from exposure to elevated levels of particles. Symptoms may include: irritation of the eyes, nose and throat; coughing; phlegm; chest tightness; and shortness of breath. At greatest risk from particle pollution are people with heart or lung disease, older adults (possibly because they may have undiagnosed heart or lung disease), and children. (Air Now)

Such tranquility can be deceiving. Germany this year was stirred into a frenzy by court ordered Diesel-Fahrverbot  (Diesel vehicle prohibitions) in many larger cities. The country is in uproar because entire classes of diesel cars (except the very latest models with the latest class of technology) may not be able to enter large parts of most polluted areas in many German metro areas. In the German rustbelt city of Essen, even the Autobahn 40, a lifeline of the entire region is included in the ban.

German news channel announcing installation
diesel prohibition signs in German cities (Photo: Philipsen)

If truly implemented (nobody has a clear strategy how to enforce the restrictions for which all those cities busily install traffic signs) the mobility and economy of entire regions would collapse. The dire situation came suddenly, in part caused by a test by the University of West Virginia which uncovered first the ever wider criminal methods with which the German car industry cheated consumers. Restitution was paid out mostly in the US, German car buyers went empty handed. Then came the courts stirred by one particular activist clean air organization.

Before that, cities and regions ignored the pollution limits established by law  year after year, just as here. But unlike the US, German cities and States don't have mandatory mitigation plans. Meanwhile, the measurements for particle and NOx pollution  aren't hard to find there. Frequently they are displayed in real time on large electronic displays right where the pollution is worst. Eventually activist Jürgen Resch, of the Deutsche Umwelthilfe (DUH) began to sue one city after the other and each time their organization won, forcing cities to take action against the worst contributors, the diesel vehicles. This was certainly facilitated by the diesel scandal around NOx emissions for which some top auto managers already sit in prison.

Hazardous air pollutants: These are either deadly or have severe health risks even in small amounts. Almost 200 are regulated by law; some of the most common are mercury, lead, dioxins, and benzene. “These are also most often emitted during gas or coal combustion, incinerating, or in the case of benzene, found in gasoline,” Walke says. Benzene, classified as a carcinogen by the EPA, can cause eye, skin, and lung irritation in the short term and blood disorders in the long term. Dioxins, more typically found in food but also present in small amounts in the air, can affect the liver in the short term and harm the immune, nervous, and endocrine systems, as well as reproductive functions. Lead in large amounts can damage children’s brains and kidneys, and even in small amounts it can affect children’s IQ and ability to learn. Mercury affects the central nervous system.
Polycyclic aromatic hydrocarbons, or PAHs, are toxic components of traffic exhaust and wildfire smoke. In large amounts, they have been linked to eye and lung irritation, blood and liver issues, and even cancer. In one recent study, the children of mothers who’d had higher PAH exposure during pregnancy had slower brain processing speeds and worse symptoms of ADHD. (The Natural Resources Defense Council). 

There are, however, some key differences between Baltimore and say, Stuttgart, the City with Germany's worst air quality in terms of particle and NOx emissions.

Air quality index colors, code green to purple 

The Weather Channel rates Stuttgart's air today as "unhealthy for sensitive groups". Baltimore's rating for this fall day is "good". Stuttgart is on two of three pollutants: particles and NOx . For the Air Qulaity Index (AQI), the third metric is ozone, Baltimore's chief culprit.

With those three measures Germany's AQI becomes problematic in the winter and Baltimore's in the summer. The critical component in Baltimore is ozone and the critical component in Stuttgart is NOx and particles. Stuttgart's sun is hardly ever strong enough to truly cook the dirty air in the same way as Baltimore's heat can do it, while Germany's dominance of diesel vehicles (more passenger cars have diesel engines than gas engines) brings up the particle count, especially in the winter when engines often run in cold mode and the airflow isn't cleaning out the air in Stuttgart's bowl shaped center as it does in the summer with warm days and cool nights.

Both countries have made great strides in overall air quality. For example sulfur from burning oil has gone way down,  lead free gasoline has practically eliminated lead from the air and catalytic converters have drastically cleaned most pollutants from cars.

In spite of growth, pollution is down (Pink, purple lines)

This may explain the long lasting apathy against the remaining violations. With Trump in control of the EPA and Hogan in Annapolis, there is little risk that politicians would all of a sudden clamp down on the non attainment, especially since oversight resides with the federal EPA. But the German government wasn't eager to disturb the cheating auto industry either. But as the recent German situation shows, law-suits can upset the apple cart in short order and leave politicians scrambling for compliance.  In spite of all the panic overseas, it is unlikely that it will come to actually closing down entire central cities to most vehicles on the road. Those yellow jackets in France just proved how quickly drastic environmental measures can run into a wall of popular unrest when large portions of the population are hit hard. Yellow vests have already been sighted in German cities as well.

Sources of NOx pollution: Transportation leads with over 60%

Meanwhile, Baltimore's air is worst in the poorest neighborhoods, and unlike in Stuttgart, Baltimore's pollution isn't mostly caused by diesel cars but comes out of state.

The Maryland Department of the Environment estimates that 70 percent of the ozone pollution that often makes the Baltimore and Washington regions’ air unhealthy to breathe blows in from outside the state, according to MDE Secretary Ben Grumbles. The lawsuit seeks to require 36 generating units at 19 plants in upwind states to install the same scrubbers and other air-cleaning technology that Maryland requires plants within its borders to install. (SUN)

Because we happen to sit downwind from coal fired power plants in other states, Maryland's legal action has come from the State itself. Maryland's Attorney General has sued the EPA over those polluters under the "good neighbor" principle, an approach that has worked in the past. But not to be mistaken, there are plenty local sources as well, some are "low hanging fruit" for elimination: Chiefly Baltimore's incinerator, the single largest source of local emissions for certain pollutants. "The facility processes more than 700,000 tons of trash each year just as many tons of CO2. It releases about 120 pounds of lead, 60 pounds of mercury, 99 tons of hydrochloric acid and 2 tons of formaldehyde, according to the Maryland Department of the Environment" (SUN). But because it also generates energy from waste, it is still classified as green energy.

US map of days with elevated ozone layers: Dirty coasts

Transportation still is a significant source of pollution in our metro area. Not for the few diesel passenger cars, but for ships, train engines, trucks and buses, all large contributors of the transportation based air pollution and all propelled by various forms of diesel. Ships burn cheap heavy oil and are huge polluters not covered by the low sulfure diesel regulations placed by EPA for trucks and cars using diesel. Train engines can also emit a lot of NOx and particulates, especially when they are older switching engines which do not use the hybrid diesel electric propulsion of heavy freight engines. Washington DC, for example, had identified switching engines as their primary polluters after they gauged emission sources to find a good use of the Volkswagen diesel fraud penalty money which has been distributed to all states which had sued Volkswagen.

Air pollution can not only be faught by eliminating sources, it can also be mitigated. In Stuttgart experimental particle absorbers have been installed at the dirtiest intersections. In Baltimore as in many other cities trees have been identified as great air scrubbers. They collect particles, dust and CO2 and cool the air while emitting oxygen. A big effort is underway to plant more trees all over the city. In that context, the Mayor's order to place a large Norwegian spruce tree, cut from Druid Park, as a Christmas tree in front of City Hall caused much consternation. But the much bigger problem is that most Baltimore street trees are planted with so little thought about what a tree needs to grow and thrive, that most never grow tall before they die from lack of water or appropriate soil and barely contribute as scrubbers and the cherished "tree canopy".

Baltimore area heat map: The urban heat island

Mitigation on a bigger scale could come form air flow that can dislodge dirty air from neighborhoods or downtown. The natural feature, is hardly studied in the US, though.

Not so in Stuttgart. Thanks to the already noted shape cup shape of downtown at the bottom of a large bowl surrounded by hills, stagnant air was a huge problem there, because foul hot air was trapped inside the cup. This has made geography and topography an object of intense studies since the seventies. What was found is that air flows downhill at night, when it cools down, especially in green areas which are not subject to the urban heat island effect. The air flow of colder, fresher air into the cup would push the dirty air out if access to the valleys is kept open and unobstructed. Initially the researchers found that many buildings were blocking and plugging up the air flow. Eventually the masterplans and urban design rules were modified so that buildings in the main air flow channels were either prohibited, limited in size or regulated to stand in the direction of the lowest resistance and  parks were enhanced to become a "green lung" for the city. Having seen the infrared photography for Stuttgart and the resulting planning steps in their early phases when I was a member of a local borough council, I suggest to study air flow here as well. It could very well be at work in Baltimore as well and that ignoring its doings would result in unintended blockages and untapped green resources here as well.

The air is cooler over Leakin Park, the Jones Falls Valley, Druid Park and Cylburn Arboretum than downtown. Thus these parks could act as a "green lung" here as well and the Jones Falls valley would be a natural air flow conduit with the terrain sloping towards the harbor.  Except that the JFX and a number of structures placed in the valley act as barriers and additional pollution sources. However, aside from "heat sink" imagery, no thermal flow analysis was ever done here to me knowledge, at least not with the purpose of studying air flow, air exchanges and the City's natural ability to "breathe".

An environmental walk in Curtis Bay
(Photo Philipsen)

With all the talk about sources and mitigation measures, one should not forget that people continue to suffer from Baltimore's poor air quality. To make matters worse, air quality is the worst in the poorest neighborhoods thanks to a longstanding urban planning practice of putting polluting and undesirable uses where the poor people are supposed to live.

Poor neighborhoods typically also have the lowest tree canopy, the lowest number of public green and parks and the busiest streets with heavy truck usage. No wonder then, that residents suffer from asthma and other air pollution related ailments, impacts that significantly contribute to the huge health disparities between neighborhoods in Baltimore which can be as large as 20 years. Baltimore's recent Green Network Plan begins to address those inequities and could be augmented to consider "green urban lungs".

It is time that Baltimore awakens to the reality that its air is far from what it should be, especially since the air usually doesn't blow from the Bay or the Atlantic. The need for local activism is especially high when the federal government is relaxing standards on clean air. Baltimore needs to attack air pollution as what it is, a significant health hazard and an another building block in the region's large disparities and inequities.

Klaus Philipsen, FAIA