Automotive Industry Trends

Air pollutants: The numbers are in - and down

Issue Table of Contents

Air pollutants: The numbers are in - and down Diesel gains ground as an environmental option Clearing the air: A look at smart pollution-busters Automotive Emissions Standards and Related Publications

The U.S. Environmental Protection Agency recently released its latest figures on air quality, and the agency’s news is bound to make everyone breathe a little easier. According to the 2002 Trends Report released in October 2003, the six principal air pollutants tracked nationally have been falling steadily for more than 30 years. Since 1970, emissions of the big six have fallen 48 percent. During that same time, energy consumption rose 42 percent and vehicle miles jumped a whopping155 percent.

The big 6
Of 188 toxic air pollutants regulated by the Clean Air Act amended in 1990, six emerge as the dirty half-dozen. These principal pollutants are:

• Carbon Monoxide (CO)
• Nitrogen oxides (NOx)
• Ground-level ozone (O3)
• Particulate matter (PM)
• Sulfur dioxide (SO2)
• Lead (Pb)

Automobile exhaust contributes to four of the big six air pollutants. The EPA estimates motor vehicles cause approximately 60 percent of the CO pollution nationwide, and in some cities, that number jumps to more than 90 percent. Nitrogen oxides (NOx), particulates and ground-level ozone, which is the major constituent of smog, are also tailpipe toxins. However the Alliance for Automobile Manufacturers points out that only about one quarter of smog-related emissions now come from cars and light trucks in key U.S. cities, despite the fact that American drive time is up from 8,685 miles per driver in 1969 to 13,476 miles per driver in 1995.

That’s because today’s clean-running cars do much to mitigate increases in miles driven. The Alliance points out that on average, cars and light trucks run 96 percent cleaner than they did in the1960s. Now that the EPA’s strict Tier 2 tailpipe emission regulations are rolling off assembly lines in 2004 vehicles, cars will run 99 percent cleaner than their 1960s counterparts.

Airborne lead pollution is also an auto industry triumph. According to the EPA, concentrations of lead in our air dropped 93 percent between 1982 and 2002. This is due to the phase-out of leaded gasoline and the 1975 launch of the first catalytic converters. Today, most lead emissions in the U.S. are billowing out of industrial chimneys.

The EPA uses more than 5,200 monitors in over 3,000 locations coast-to-coast to track air quality measurements. Although the news from that effort is largely positive, there are still a few dark clouds on the horizon. Currently, nearly 160 million tons of pollution dim U.S. skies each year. And while the big six contaminants have decreased, at some point last year, 146 million people still choked their way through air the EPA considers “unhealthy.”

Less fuel, less pollution
One factor contributing to today’s improved air is auto fuel efficiency, and the Alliance of Automobile Manufacturers notes that economy rates nearly doubled between 1974 and 2000, jumping from 14.2 miles per gallon to over 28. According to the EPA, choosing a car that gets 25 miles per gallon instead of 20 will cut greenhouse gas emissions by about 15 tons over the average lifetime of a vehicle. That’s easy to believe when you look at the EPA’s Fuel Economy Guide for model year 2004 cars and trucks. Among the environmentally friendly pack cited by the EPA are:

If you’re looking for a green ride, you’ll find a complete report on 2004 cars at www.fueleconomy.gov.