I've recently been trying to lose weight and am rather pleased with the results. However, there is one instance every day when the craving for food becomes almost agonising.

I have to pass a small food stall in the morning which serves bacon sandwiches. The smell drives me crazy and I'm desperate to buy one, so much so that I've changed my route to work to avoid it.

A vegetarian friend also tells me that the one smell that could almost make her start eating meat again is that of bacon grilling.

So what has cooking bacon got in it that makes it so tempting?

Peter Hodge, Leicester, UK

It is very distinctive and seems unchanged over decades and brands, but does it come from paint, plastic or something else? And if so, why is it the same across all cars? Or have the manufacturers bottled a fragrance which they secretly spray to seduce new car buyers?

William Coley, London, UK

3 of us tried to quit smoking while working at a typewriter repair shop where we used strong chemicals to clean the machines. For some reason the smell of the chemicals made us laugh uncontrollably. Only while we we're trying to quit. None of us ended up quiting and when we started smoking again, no more laughing like crazy Why did that happen?

I noticed it first when I had a sandwich that had some tomato relish in it. As soon as I brought the sandwich to my mouth to take a bite, I immediately got a strong smell of acetone - at least that is the closest smell I can think of. It didnt smell like any kind of food and I couldnt smell it for long without having to take it away again it was so strong. I decided then that there was just something wrong with the sandwich. But later when I was chopping tomatoes I got the smell again, so I decided to test with a few other items - ketchup was the only other thing I had that gave me the same smell. I tested them and no one else smelt anything out of the ordinary. So presumably it was caused by some mucus in my nose at the time. Was it a chemical reaction in my nose that caused the strange smell?

2 days later and tomatoes smell normal again - the strange thing is, I still have a cold.

Paul Abbott, Durham, UK

Right after I sneeze, there is quite a strong, very distinctive smell. It's unlike anything else. What causes it?

Are there any other foods which affect urine this way? And why do people often report not noticing the smell until someone else points it out?

Every now and again I find that everything smells sickly sweet, like bubble gum or very sweet bananas. This often lasts a few days, with nearly every inhale through my nose giving this sensation. What's going on? Have I got a piece of banana rotting away in my nasal cavity? Did my excessive pot-smoking during university have an unusual effect on my brain? Or does the world actually smell like bananas every so often?!