For a sheer grams-for-grams comparison, you’d need to know the power level for the small engine.
Let’s take a lawn mower. I’ve got a battery-powered mower these days, but my previous model had a 4-horsepower engine (3 kW). To be fair, let’s assume it doesn’t run at full rated power all the time; let’s assume an average of 2.25 kW during normal operation. So if I operate it for an hour, that’s 2.25 kW-hours. Based on the numbers in your post, that means in one hour my old mower was allowed to put out:
HC+NOx: 225 grams
CO: 1235.25 grams
For cars (“light duty vehicles”), I found this table:
Take a late-model car, say, 2018. estimated emissions are as follows:
HC+NOx: 0.584 grams per mile
CO: 4.646 grams per mile
So if we compare HC+NOx, then operating my gas mower for an hour is equivalent to driving a MY2018 car about 385 miles. Comparing CO, it’s the equivalent of 265 miles. If you want to come up with some kind of crude average, you might say operating a mower for an hour is like driving a car 300 miles.
That’s a lot less than the 1100 miles described in the OP. However, the table I linked to is for average emissions, and includes all modes of operation: cold start (summer+winter), idle, city driving, and highway driving. The OP’s scenario described driving a Camry from LA to Denver. That’s all highway miles, with maybe two cold starts. The total emissions for that journey will be a lot lower than the emissions for the aforementioned “average” driving. It’s entirely plausible that running a mower for an hour is like driving a car from LA to Denver, at least on the basis of noxious pollutants (HC, CO, NOx).
For CO2, it’s a different story. As noted, CO2 output scales almost perfectly with fuel consumption. For a 2018 Camry with a V6 engine, the highway fuel economy is 33 MPG. Not sure about my lawn mower, but I think in an hour it used to burn maybe a pint of gas. In other words, running my mower for an is equivalent to driving a Camry about 4 miles down the highway.
@Musicat asked about a gas-powered leaf blower though, not a lawn mower. The former tends to have lower power ratings than the latter, but not by a lot. This backpack leaf blower is rated for 2.8 ps, or 2.06 kilowatts
While less than my mower, a leaf blower tends to run all-or-nothing, so in an hour’s time you’d expect an honest 2 kw-hours of work out of it - not much less than the 2.25 kw-hours I estimated for my mower. I’m still confident that this compares fairly with an 1100-mile highway journey by a late-model mid-sized sedan.
@Musicat 's claim was that two different machines designed for two different jobs running for two wildly different periods of time gives us very similar results.