Hiking in the rain often left me with thoughts about acid rain. I wonder if I'm able to recognize it and if yes, how strong the recognizable symptoms are.

Are there any direct (forest dieback etc. is indirect) harms for humans and animals (like burning skin etc.)? If yes, how should I react when "stuck" in acid rain?

  • 9
    Acid rain is not something that just suddenly happens, it is the result of air pollution (sulfur and nitrite oxides). Sure there are lightnings and volcanoes, but in both events acid rain really is not what you should be worried about. And acid rain is just very little acidic, the problem for the environment is the accumulating effect over a long time. This really is nothing to be momentarily worried about, only in the big picture.
    – imsodin
    Commented Aug 8, 2016 at 14:56
  • Just don't fall into acidic hot springs.
    – gerrit
    Commented Aug 8, 2016 at 16:25
  • If you are hiking in and area with enough air pollutants to produce acid rain then you need to hike some where else.
    – paparazzo
    Commented Aug 8, 2016 at 17:30
  • 2
    @pap: You might be hiking in a clean area, with the air pollutants entering the system a long way upwind. In fact, it seems that some time is required for the pollutants to cause acid rain. There result is therefore usually well down wind of the source. For example, back in the 1990s, the White Mountains of New Hampshire recorded significant acid rain that was traced back to coal-fired power plants in the Ohio Valley. Commented Jun 24, 2018 at 12:00
  • @OlinLathrop If pollutants have entered then it is not a clean area.
    – paparazzo
    Commented Jun 24, 2018 at 12:05

1 Answer 1


Acid rain usually has a pH of around 4-5, while normal rain is around 5.6, and pure water is 7, or neutral [1] [2]. To give that in perspective, acid rain is less acidic than orange juice or soda, while normal rain is closer to bananas [3].

You shouldn't be in danger from the acid rain itself any more so than normal rain. However, you are more in danger from the pollutants which cause acid rain, such as sulfur dioxide and the various nitrogen oxides [4].

Acid rain has more of an effect on wildlife, where it can interfere with the hatching of fish eggs (most of which cant hatch below a pH of 5), as well as leaching aluminum from the soil into lakes and streams. Additionally, it can remove nutrients from the soil, as well as damage stone and metal sculptures [4].

In conclusion, you should not be directly effected by acid rain, though the pollutants which cause it can harm you, and it will harm the environment in a bunch of different ways.

  • I wonder what the health effects would be of hiking in a rain made of soda. The fact that it's less acidic than an (unhealthy!) drink doesn't say much about being rained on by one vs. drinking the other.
    – gerrit
    Commented Apr 26, 2022 at 12:23

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