Would you expect there to be more smog on a cloudy day or on a clear day?

You would generally expect more smog on a clear day. This is because sunny conditions can lead to increased temperatures and sunlight, which promote the chemical reactions that create smog from pollutants. On cloudy days, the lack of sunlight and cooler temperatures can help reduce the formation of smog, as atmospheric stability is often higher and pollutants are less likely to accumulate.