This compares to 1,374 tons per day statewide for passenger cars. While reductions from gasoline SI marine engines are not included in California’s SIP as a planned measure for meeting attainment goals, the impact of outboard and personal watercraft engines on the state’s total emissions inventory makes control of this category of emissions necessary. Table 1 lists the relative contribution of outboard and personal watercraft exhaust emissions in California in tons per day. As a comparison to other sources, the exhaust emissions from two hours of personal watercraft operation is equivalent to the emissions from a 1998 passenger car operated over 100,000 miles.
The sentence in bold created a lot of confusion, since Stienstra (1998) wrote an article, cited the report and paraphrased it like this:
The state Air Resources Board is also considering taking statewide action against personal watercraft, after a staff report said that two hours of exhaust emissions from a Jet Ski is equivalent to the emissions created by driving a 1998 automobile 100,000 miles.
While users in skeptics.stackexchange.com interpreted as:
Two hours of use of a jet-ski produces the same pollution as two hours of driving a 1998 car with 100,000 miles on the clock. (And not driving a 100,000 miles with that car).
Another user here found another interpretation:
All the watercrafts operating in California together produce in 2 hours the same pollution as one car driven 100,000 km.
Is Stienstra (1998)'s interpretation the intended meaning and why? Could we be 100% sure?
Stienstra, T. (1998, Jul 08). U.S. park service seeks ban on jet skis 950 square miles of bay area waters would be affected. San Francisco Examiner. Retrieved from http://search.proquest.com/docview/270486538?accountid=8555