The main culprits are pollen from imported grasses, weeds and trees, which are wind pollinated. Pollen can also enter the home through open doors and windows as well as on clothes that may have been exposed to the elements. Products such as air purifiers can be effective in helping to remove triggers such as pollen and pollution from the air.

Some people are also sensitive to the effects of chlorine in pools and spas. Look out for products that avoid chlorine and bromine, but still keep pools and spas clean.