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So although I've mostly avoided wildfire smoke, here I am in Mexico City, where the air is bad by default, with AQI around 150 today.
AQI is a weird non-linear index. For PM2.5, the main culprit here:
ug AQI (ug = micrograms per m3)
5 21
10 42
12 50
16.3 60
20 68
25 78
30.6 90
35.4 100
40 112
50 137
55.4 150
100 174
250 300
500 500
5 ug is the WHO's new recommended maximum for air safety, down from 10, or the EPA's 12. You can see AQI starts out at 4x ug, becomes more like 3x for the region of modest concern, and ends up nearly linear. Also that AQI 150 is over 10x the WHO safe limit (after converting to ug), or 4x the EPA's.
Thing is, I've got respirators. Even a 90% reduction turns that 55.4 ug down to nearly 5 ug. 99% reduction turns even AQI 500[1] into safety. Should be nice and safe to go outside.
Buuut I spent the day reading inside, in my bedroom with the air purifier on. And wearing a mask too (3M 8511, valved) because why not, it's actually pretty comfortable. I have stuff I want to do inside, I might as well do it during the hell period.
[1] The official EPA scale maxes out at 500, though I think I saw reports of 2000s when Australian cities were being wreathed in smoke last summer, so either my memory is wrong, someone extended the scale, or AU has their own AQI scale.
https://www.hindustantimes.com/cities/500-what-a-maxed-out-aqi-means/story-Zg0gUMnSKCZKEAu0iry62J.html seems to say the health damage plateaus... also that India's safe level is 60 ug. Eek.
AQI is a weird non-linear index. For PM2.5, the main culprit here:
ug AQI (ug = micrograms per m3)
5 21
10 42
12 50
16.3 60
20 68
25 78
30.6 90
35.4 100
40 112
50 137
55.4 150
100 174
250 300
500 500
5 ug is the WHO's new recommended maximum for air safety, down from 10, or the EPA's 12. You can see AQI starts out at 4x ug, becomes more like 3x for the region of modest concern, and ends up nearly linear. Also that AQI 150 is over 10x the WHO safe limit (after converting to ug), or 4x the EPA's.
Thing is, I've got respirators. Even a 90% reduction turns that 55.4 ug down to nearly 5 ug. 99% reduction turns even AQI 500[1] into safety. Should be nice and safe to go outside.
Buuut I spent the day reading inside, in my bedroom with the air purifier on. And wearing a mask too (3M 8511, valved) because why not, it's actually pretty comfortable. I have stuff I want to do inside, I might as well do it during the hell period.
[1] The official EPA scale maxes out at 500, though I think I saw reports of 2000s when Australian cities were being wreathed in smoke last summer, so either my memory is wrong, someone extended the scale, or AU has their own AQI scale.
https://www.hindustantimes.com/cities/500-what-a-maxed-out-aqi-means/story-Zg0gUMnSKCZKEAu0iry62J.html seems to say the health damage plateaus... also that India's safe level is 60 ug. Eek.