Final answer:
Nitrogen Dioxide (NO2) is the indoor air pollutant produced by properly operated gas ranges in kitchens, which can cause respiratory issues and exceed outdoor levels in homes with gas stoves.
Step-by-step explanation:
The question asks about the source of the indoor air pollutant that can be produced by properly operated gas ranges in kitchens. Among the options provided, the correct answer is Nitrogen Dioxide (NO2), which is known as one of the nitrogen oxides (NOx). Gas stoves and ranges can emit NO2, which can exceed outdoor levels inside homes that use these combustion appliances. NO2 can cause adverse effects such as eye, nose, and throat irritation, increased risk of respiratory infections, and shortness of breath. Although Carbon Monoxide (CO) is also a combustion pollutant, it was not one of the options provided, but it is worth noting that it can also be produced by gas stoves, particularly if they are improperly adjusted or not vented adequately.