Alliance of Automobile Manufacturers Testimony on EPA’s Proposal to 

Retain the National Ambient Air Quality Standards for Carbon Monoxide 

76 Fed. Reg. 8158 (February 11, 2011) 

February 28, 2011 

My name is Giedrius Ambrozaitis and I am here today representing the Alliance of Automobile 

Manufacturers. The Alliance is an association of 12 vehicle manufacturers including BMW 

Group, Chrysler Group LLC, Ford Motor Company, General Motors Company, Jaguar Land 

Rover, Mazda, Mercedes-Benz USA, Mitsubishi Motors, Porsche, Toyota, Volkswagen Group 

of America and Volvo. 

The Alliance members recognize the importance of ensuring clean air and setting air quality 

standards at a level that protects public health. Our air is cleaner today than it was a 

generation ago, and air quality is continuing to improve. 

Our nation’s air is getting cleaner even as our economy grows and vehicles travel more and 

more miles. According to EPA’s most recent air trends analysis1, since 1990, nationwide air 

quality has improved significantly for the six common air pollutants. Nationally, over this time 

period, ozone has decreased 14 percent, fine particulate matter has decreased 19 percent, 

nitrogen dioxide has decreased by 35 percent, sulfur dioxide has decreased by 59 percent and 

carbon monoxide has decreased by 68 percent. Investments and improvements in vehicle 

technology and manufacturing processes are a major part of this success story. Today's 

vehicles are 99% cleaner than vehicles of the 1970s, thanks to dramatic reductions in smogforming emissions. 

Further, significant additional emission reductions will occur over the next 20 years as a result 

of already promulgated regulations for mobile sources. According to EPA’s own statistics, 

emissions from cars and trucks are expected to be reduced by an additional 70 percent by 

2030. These reductions will help to reduce criteria pollutant concentrations across the country, 

and the improvements to air quality as a result of these reductions will continue to occur. 

                                                           

1 EPA, Our Nation’s Air – Status and Trends Through 2008, available at  http://www.epa.gov/airtrends/2010
 

The Alliance supports EPA’s proposal to retain the current levels of 9 ppm over 8 hours and 35 

ppm measured over 1 hour for the carbon monoxide NAAQS standard. As EPA notes, the 

science shows that the current standards will protect people, especially those susceptible to 

health problems associated with breathing CO from the outdoor air. We agree with EPA’s 

conclusion that the current standard provides a very high degree of protection for the 

carboxyhemoglobin (COHb) levels and associated health effects of concern. The current suite 

of standards provides an adequate margin of safety against adverse effects associated with 

shortterm ambient CO exposures. The Alliance agrees with the Administrator that the 

uncertainties and limitations of the epidemiological evidence are too great to provide a basis 

for revising the current standards. We note that retaining the current standards is also 

consistent with the advice EPA received from CASAC, EPA’s own scientific advisory panel. 

As I noted, EPA’s monitoring data indicates that ambient carbon monoxide concentrations 

continue to fall as cleaner and cleaner vehicles enter the fleet. EPA’s website indicates that 

carbon monoxide levels decreased 80 % between 1980 and 2009. The ambient levels of CO 

have continued their steady decline over the past several years. From 2001 to 2008, 

concentrations of 8-hour carbon monoxide decreased 41%. There are currently no areas 

designated as nonattainment. 

The Alliance is still evaluating EPA’s proposal to revise the air monitoring requirements for CO. 

Our initial reaction is that the proposal needs further consideration. As the proposal notes, the 

monitoring of CO in peak microscale locations has been a high priority since 1979. The 

proposal to move existing monitors to be co-located with near-roadway NO2 monitors raises 

several questions and concerns. The locations of these monitors will be close to the most 

heavily travelled segments of the most heavily travelled expressways. As such, this 

approaches peak source monitoring rather than monitoring locations that represent population 

exposures. 

Monitors should be located where there are people exposed to peak 1-hour or 8-hour CO 

concentrations. However, the proposal does not include a requirement that the monitoring 

sites be locations where people are actually exposed to CO for such times. It should. 

If non-attainment is determined at a proposed near-road microscale site, which has a spatial 

scale of representativeness of from a few meters up to 100 meters, what is the size of the nonattainment area that would be designated? Since the location is dominated by the traffic 

source, what kind of a SIP would be required? Since the current motor vehicle regulatory 

program will continue to reduce on-road emissions, would the requirement to develop a SIP be 

redundant and wasteful? Questions such as these need to be considered by the Agency 

before the rule is finalized. 

The proposal lists several benefits from the proposed changes to the monitoring network. One 

benefit noted is that the overall network would be smaller. The Alliance is concerned, 

however, that with the proposed changes on top of the movement of sites to the new NCore 

monitoring network, the nation will lose many sites that can be used to determine nationwide 

trends. Maintaining a consistent set of sites to determine long term trends should be a priority 

for the Agency. 
 

Another benefit listed is that the sites will provide data that can support health studies. 

However, fixed microscale sites that are located to be close to the very highest traffic density in 

a city will not be particularly useful for health studies. Personal exposure monitoring of 

populations that live close to roadways would provide much better information on the 

distribution of their CO exposures. 

The proposal indicates that the data can be used in verification of modeling results. However, 

to verify modeling results requires a different study design, one that does not require 77 new 

monitors in different cities. A smaller set of well-designed monitors at various distances from 

the highway along with detailed meteorological measurements around the roadway would be a 

much better approach to verify roadway dispersion models. 

Finally, the proposal indicates that the data would useful to estimate in-vehicle on-roadway 

exposures. Again, a research program to measure such exposures directly would be a much 

better method to gather such information. 

The Alliance appreciates this opportunity to comment. We will also be submitting written 

comments on the proposal in April. I would be happy to answer any questions.