Recently I attended the biannual meeting of the Clean Air Act Advisory Committee (CAAAC), a federal advisory committee of the Environmental Protection Agency on which I serve. At the meeting, we were presented with a draft report from the Urban Air Toxics Workgroup. For the last year, the workgroup has been studying the threat of toxic air pollution in urban environments and crafting a set of recommendations for action. One of the co-chairs of the Workgroup is our friend Jalonne White-Newsome, the Federal Policy Director for WE ACT for Environmental Justice.
At the CAAAC meeting, the Urban Air Toxics Workgroup presented a Draft Report with a notable feature. Only one pollutant was singled out by name: diesel exhaust. In fact, of the twenty-five recommendations made in the Draft Report, four of them identified needed actions on diesel exhaust and diesel particulate emissions. They are as follows:
Recommendation No. 3: EPA should request that the National Toxicology Program (NTP) evaluate the carcinogenicity of diesel exhaust.
Recommendation No. 4: EPA should collaborate with other federal agencies to expedite the retirement of the diesel engine legacy fleet.
Recommendation No. 5: The EPA Administrator should advocate for the issuance of an Executive Order to require clean diesel technology (or other lower emissions technology) engines be used in all federally funded infrastructure projects.
Recommendation No. 10: EPA should encourage supplemental environmental projects that focus on reducing urban and tribal areas’ exposure to air toxics, with a particular focus on diesel particulate emissions. Likewise, EPA should encourage state enforcement authorities to prioritize projects that reduce urban and tribal area air toxics as part of state compliance agreements.
This significant focus on diesel exhaust in the Urban Air Toxics Workgroup Draft Report was not lost on CAAAC members. At the meeting, the question was asked: is diesel exhaust really the pollutant of greatest health concern in urban environments?
Now, this is not a simple question. To take a particularly difficult example, consider the various air pollution health threats in Houston: ozone, fine particulate matter, diesel, metal aerosols, vehicles, the Houston Ship Channel, the petrochemical industry, energy generation, etc., etc.
Can anyone confidently rank these risks in Houston? Does metal recycling present more risk than aging school buses? Are barges burning dirty fuel worse than coal-fired power plants? We simple don’t know. These problems are complex and varied, and no one has even attempted a relative risk ranking, to say nothing of a cumulative risk analysis.
But one thing is certain: the Clean Air Act Advisory Committee represents a serious brain trust of individuals working in the field of air pollution and public health. So when the question was put to the Committee, you can be confident the answer is one of the best you will get.
So: is diesel exhaust the air pollutant of most concern in urban environments? The consensus among CAAAC members was that it probably is. The more we learn about diesel, the worse its impacts seem. The recommendations of the Urban Air Toxics Workgroup illustrate the urgent need to act on diesel pollution from several fronts.
In closing, I will remind you about the Moving Forward Network (of which we are founding members) and its Zero Campaign to end emissions from goods movement. When the Zero Campaign is successful, we will have eliminated the health problems created by diesel exhaust. But the Zero Campaign will only succeed with the combined efforts of the Moving Forward Network, the EPA, the Clean Air Act Advisory Committee, the Urban Air Toxics Workgroup, and you.
If you haven’t done your part by signing our petition, please, Take Action now.