In certain situations - near waterfalls, where the sea breaks onto rocks, in pine forests, mountain areas and following lightning storms, you may notice you feel invigorated and refreshed, because you've been breathing air with a high content of small negative ions of oxygen.

The so-called 'witch's winds' are winds called the Foehn in Switzerland, Sharav in the Middle East, the Mistral in France, the Sirocco in Italy, California's Santa Ana, Sydney and Brisbane's Westerlies, Melbourne's Northerlies, Perth's Easterlies and Adelaide's Northerlies - all have long been traditionally blamed for causing illness, accidents and depression.