Passage Summary: Gas mowers are surprisingly dirty, so if people switch to clean electric versions, the air will get better.

Conclusion: Switching from gasoline-powered lawn mowers to electric ones is an effective way for people to help decrease air pollution.

Reasoning: Gas mowers emit as much pollution per hour as cars and are major contributors to summer smog, whereas electric mowers produce no air pollutants during use.

Analysis: The argument assumes that the 'zero emissions' of the electric mower at the point of use results in a net benefit for the environment. To strengthen this, we could find an answer that addresses the 'hidden' pollution of electric mowers, such as confirming that the electricity generation process is still cleaner than burning gas in a small engine. Additionally, evidence showing that people use these mowers frequently enough to make a statistical impact on summer air quality would bolster the conclusion.