I’m in New York right now and I’m seeing a lot of news / government warnings to stay indoors due to the wildfire smoke.

For example: Stay indoors, mask up: Staying safe as ‘hazardous' smoke levels choke NYC area

I don’t have an air purifier in my home. So is my indoor air actually safer? How is the air getting filtered?

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    @JoeW There's a huge wildfire going on in Canada for the past week or so. The smoke has drifted down to northeastern US, and it's causing terrible air quality along the eastern seaboard.
    – Barmar
    Commented Jun 9, 2023 at 15:00
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    @Barmar I understand that but the question just asked if staying indoors reduced wildfire smoke and I was asking for more details about what was being asked as that didn't make any sense to me. A question should include details from the claim so that people don't need to read third party sources to understand what is being asked. As the question has been edited it makes a little more sense as to what the claim is as it isn't reducing wildfire smoke but protecting you from it.
    – Joe W
    Commented Jun 9, 2023 at 16:20
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    @Barmar I know that but as I said people should not have to visit a third party site to understand the question.
    – Joe W
    Commented Jun 9, 2023 at 23:18
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    Your carpet, sofa, curtains, clothing, walls etc. adsorb the smog particles (very effectively) so you don't breathe them in any more, and you get rid of them with the next run of the washing machine, or next spring cleaning.
    – Karl
    Commented Jun 11, 2023 at 21:14
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    If you have central HVAC in your home, you have an air filter/purifier, at least a primitive one. Commented Jun 11, 2023 at 22:11

1 Answer 1


Yes, for some time.

Your home acts as gas-reservoir for a time.

International Energy Agency’s information centre on energy efficient ventilation. writes

Evacuation of people from their homes and workplacesis a standard response to the hazards created by the release of toxic gas. However by staying indoors a person can take advantage of the clean air stored within the house volume, as well as the damping the house provides for sudden changes in outdoor toxic gas concentration. The relation between indoor and outdoor concentration is explored in this study, where it is shown that in most cases the risk of exposure to high concentration levels is substantially reduced by remaining indoors during the entire period of toxic gas release. Ratios of indoor to outdoor concentration are presented for typical rates of air infiltration and outdoor concentration variation

In prolonged cases your house air will run out and effect is diminished.

Your building shields your partly from fine-particles and smoke

EPA on Wildfires and Indoor Air Quality

When wildfires create smoky conditions, there are things you can do, indoors and out, to reduce your family's exposure to smoke.

However, they also suggest taking action by using portable filters:

Have a supply of N95 respirators and learn how to use them.
Indoor Air Filtration

Tl;dr: it's safer for a time, but you or your building management needs to take action. In any case, it's better then outdoors.

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    To add to this, staying indoors would be less effective when toxic gasses persist over long periods of time, but most cases aren't predicted to fall into this category (and when they do, an evacuation is likely to be ordered). And even if it does persist over long periods of time, a house with closed windows and doors may still block some of the gasses.
    – NotThatGuy
    Commented Jun 9, 2023 at 11:12
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    @NotThatGuy it's further complicated by being a mixture of gases and particulate matter. The latter can be filtered (to some extent) with readily-available materials, the former can't. The first (IEA) quote, discussing gases, is relevant, but perhaps less so than it seems, given that in the context of this question particulates are the bigger threat.
    – Chris H
    Commented Jun 9, 2023 at 13:09
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    Also, not for nothing, but people who are staying inside are definitionally not driving around in their cars (or riding in taxis, this being New York), and thus adding exhaust to the already polluted air. Reduced auto traffic doesn't make the air quality any better (in terms of wildfire smoke), but it does help to stop making it worse. Commented Jun 9, 2023 at 13:40
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    @DarrelHoffman Being shot at + drinking water from lead piping is also slightly worse than just being shot at. But does it make a ban on lead piping a viable way to address gang violence?
    – Therac
    Commented Jun 9, 2023 at 18:19
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    The difference is that those are entirely unrelated, and there's no common protection from both bullets and lead in the water. In the case of exhaust and smoke, staying indoors, using air purifiers, wearing masks, etc. all of the same measures help for both things. And reducing exhaust will reduce (even if only by a small degree) the collective strain on air purifiers, allowing them to work more effectively against other pollutants such as smoke. Commented Jun 9, 2023 at 18:26

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