I live in Chicago, and I ride through the downtown area and other congested streets to and from work every day. Often when I am at a stoplight, I am directly behind or next to several cars belching exhaust. I can't help but smell and inhale it. Sometimes I try to hold my breath, but I can't always hold it for long enough. It smells bad, and I do not wish to inhale carbon monoxide. Is there some great product out there, or maybe just some tips and tricks from other city riders, on how to avoid inhaling exhaust fumes while riding through heavily trafficked urban streets?
Edit
I believe my question is similar to or the same as the suggested duplicate about "how to protect yourself from pollution", however that question has no usable answer (The answer is basically "a gas mask would help, but of course you cant go biking with a gas mask"). I believe my question is not the same as "is pollution a problem" because I am not making/seeking a judgment on pollution, positive, negative, or otherwise, I am just attempting to avoid it/minimize my exposure.