Though the relative scarcity of air quality monitoring stations in the state makes it difficult to pinpoint changes in air quality, U.S. EPA data indicate a dramatic decline in air pollutant emissions from cars and trucks, all attributable to vehicle fleet turnover and federal emissions control mandates. Carbon monoxide (CO) emissions from motor vehicles have dropped almost 19 percent from 1997 to 2002 (the most recent year for which data is available). Nitrogen oxides (NOx) emissions from motor vehicles have fallen 20 percent. And motor vehicle-related volatile organic compounds (VOC) emissions plunged nearly 35 percent during the period. The most dramatic reduction in motor vehicle-related emissions occurred in fine particulate matter (PM 2.5). Those emissions fell almost 47 percent during this period. While heavy duty construction vehicles and other off-road mobile sources are a primary contributor of this especially harmful pollutant, light duty motor vehicles and diesel trucks are also significant sources, particularly because they are present in high numbers in virtually all locations.
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Source: US EPA, Criteria Pollutant Emissions Summary Files, 1997-2002. |
The four New Jersey cities for which air quality data was available experienced their best air quality in years in 2004. Newark had 0 days of unhealthy ozone levels in 2004, down from a high of 27 in 2002. And Jersey City had just 1 day of unhealthy ozone levels in 2004, down from a high of 17 in 1999. But the year-to-year variability shows no clear improvement in air quality, even as emissions from the transportation sector have declined. Transportation emissions may be especially concentrated in these cities so that the air quality trends don’t necessarily reflect statewide declines in emissions. In these cities, poor air quality may also be driven by emissions from non-transportation sources and/or influenced by especially hot weather.
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Source: US EPA, Number of Days with Air Quality Index Values Greater than 100 at Trend Sites, 1990 - 2004, and All Sites 2004 (Ozone Only). |