city smog

smog develops when carbon emissions react with sunlight, and the problem is not the sunlight. X

is your city on the smog list?

mysqli

coal - burning coal to produce electricity
cars and trucks - motor vehicle exhaust from internal combustion engines
wood burning - fireplaces, firepits, leaf burning and BBQ restaurants
industrial emissions - factories and methane emissions (methane venting from fracking)
fires - forest and agricultural fires
chemical - solvents