[jwph (OP)]

I live in North Philippines where we get frequent storms. I often notice, after or during a heavy shower, that the air is permeated with a very strong sulphurous smell. I'm not sure if it's hydrogen sulphide or sulphur dioxide. I'm wondering where this smell might be coming from. There is little industry here so I doubt it's from an industrial source. There are no active volcanoes though we're about 50 miles north of Pinatubo which s very quiet now. The wind generally comes from the north off the Gulf of Lingayen. I doubt if it's overflowing sewage or I'd smell that at other times. I'm wondering if an electrical storm produces some sort of chemical reaction that results in this smell. Any ideas?

[finchbeak]

I've never heard of this and I can't say I know much about it.  One possibility that occurs to me is that the storms could be stirring up sediments in some nearby body of water.  Do you live near the sea or a lake?
Also - sulfur dioxide and hydrogen sulfide smell quite different.  SO2 has an acrid, choking odor while H2S has its distinctive nauseating "rotten eggs" odor.  Your description of sewage leads me to think that you're smelling H2S.  If that's true, then I think aquatic sediments is a good guess.

[David Sparkman]

You may be smelling ozone, similar but not as strong as sulfur. Ozone of course is Oxyen 3 or O3 and is made in lightening storms. It makes me feel more alert. Some commercial companies sell air cleaners based on generating ozone. But as the material corrodes rubber and other plastics  these air cleaners haven't been too popular. Ozone is also anti-bacterial.

David

[gsmollin]

Ozone is common during thunderstorms, since the electric discharges produce it. However, it has a sweet odor, and sulphur is always sour smelling. Sulphur is not produced in a thunderstorm, so it must be carrying it from some place else.

[finchbeak]

If ozone were the odorous culprit, I think people all over the world would be familiar with a connection between thunderstorms and the "sulfurous" smell described.  I am inclined to think this is some more local phenomenon.