Map shows where low-altitude NASA airplane will fly as part of campaign to study air quality (D.C. is in lower left corner). The flight paths are in yellow. Circles indicate where the plane will spiral up or down, reaching as low as 1,000 feet (NASA)

*There will actually be two NASA airplanes flying over an area stretching from the northeast branch of the D.C. Beltway to the northeast corner of Maryland - one flying spirals from around 15,000 feet to as low as 1,000 feet off the ground, and another around 26,000 feet.

*The goal is to gather data to help improve the ability of satellites to measure ground-level air quality from space - satellites have trouble telling the difference between pollution near the surface and high in the atmosphere. Satellites are an important tool for monitoring air quality given the large gaps in ground-based pollution sensors across the country and around the world. Improved satellite measurements should lead to better air quality forecasts and more accurate assessments of pollution sources and fluctuations.

*Approximately 14 research flights are planned during the month of July, plus initial test flights that could begin this coming Sunday or Monday. Flight times can range from 6 a.m. to 8 p.m. with flights lasting up to 8 hours. If you’re really in to this kind of thing, NASA says announcements of flights will be posted to this website by 6 p.m. the day before a flight is planned.

*The campaign has a long and dizzying title: Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality. Conveniently, NASA is calling it DISCOVER-AQ for short.

Beneath the flight path are six ground stations operated by the Maryland Department of the Environment, and additional instrumentation will be provided by NASA, the Environmental Protection Agency, Howard University, Pennsylvania State University, the University of Maryland-Baltimore County, and Millersville University in Pennsylvania. Scientists will compare the data collected with that from the “A-train” fleet of NASA satellites, which will make a daily early-afternoon pass over the study area.

The D.C.-Baltimore flights mark the beginning of a four-year campaign that may include Houston and Sacramento in 2013 and other locations yet to be determined.

A number of factors lead to bad air quality, which can of course cause a host of health problems, especially for sensitive groups like children, older adults and people with lung disease such as asthma. The biggest influences include vehicular and industrial activity, wildfires, volcanoes, weather and geography. This past Sunday, for example, smoke from Canadian fires contributed to Code Orange and Yellow conditions in the D.C.-Baltimore area.

When it comes to weather (that is the subject of this blog, after all), it’s that seemingly friendly high pressure that often leads to our worst air quality days during the warm season. How come? Sunnier usually means warmer, which promotes the chemical reactions that create pollution. Also, the light or calm winds near the center of high pressure stagnate the air, allowing pollution to build up. Want some more reasons to hate on high pressure? See more here.

Our weekend forecast has only weak high pressure trying to gradually build in. So no Code Oranges (unhealthy for sensitive groups) or Reds (unhealthy) in the D.C. area air quality forecast through the weekend, just Code Yellow (moderate). So far the metro area has seen two Code Red days and five Code Orange days this year, according to the Metropolitan Washington Council of Governments.

Guide to Air Quality Index. (

4:25 p.m. Update: I asked Terry Keating, an environmental scientist with the Environmental Protection Agency’s Office of Air and Radiation, why the D.C.-Baltimore area was chosen as a starting point for the air quality campaign, and how the campaign will lead to better air quality forecasts. Here are his responses:

Why was the D.C.-Baltimore area chosen as a starting point for the air quality campaign?

I think that there are several factors that probably went into NASA’s decision to start here:

1) Baltimore/Washington’s air quality problems have similar sources and characteristics to the other urban areas along the East Coast. Air quality is mostly affected by local motor vehicles and other sources in the urban area mixed with pollutants that are transported from other states. Thus, what we learn about how to relate satellite observations to surface air quality is likely to be transferable to other cities.

2) Baltimore/Washington has some interesting local aspects, as it is affected by the land-sea effects caused by the Chesapeake Bay.

3) NASA Goddard and NASA Langley are nearby, the Maryland Department of the Environment (MDE) is a willing and capable collaborator, and there are a number of local universities already working with MDE that will supplement the NASA and EPA research efforts.

How will the campaign lead to better air quality forecasts?

Many of the atmospheric processes that drive air pollution concentrations at the surface take place in the atmosphere above the surface layer. Satellites can provide us a view of the total amount of pollution in atmospheric column above a given location, but we have hard time discerning how that pollution is distributed vertically, what is in the surface layer, what is in the lower part of the atmosphere above the surface layer, what is in the upper atmosphere.

DISCOVER-AQ is designed to tell us more about how to relate the pollution levels that satellites detect in total column measurements to how that pollution is distributed vertically in the atmosphere. With this information, we can evaluate whether our three dimensional models are giving us reasonable estimates for pollution above the surface layer and we can develop new predictive relationships for surface air quality based on observations of pollution levels aloft.