Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

A study on the extent of global air pollution

scienceswitch.com

Post reply on HN
Print view View original

61–70 of 73 posts

Re: A study on the extent of global air pollution

#61

Post by mistrial9 »

stinos wrote: post #43
cmews wrote: post #31

My wife has severe astma and when traveling this is something that worries me all the time. At home we have blue air machines and plants to filter the air, but astma attacks still happen (when she didn't use her medicines enough) when she travels from work to home on bad air quality days in Amsterdam. The astma medication is something that comes with a lot of trade-offs/health complications if you use it too much. Ho…

I don't understand why politically it doesn't get the attention it deserves Same as the obesity pandemic, the climate crisis, the biodiversity crisis: there are no clear immediate effects for the general population (consequences of that in turn lead from claims that it's fake to 'yeah sure whatever I don't care doesn't affect me' and everything in between), dealing with it will in the short run cost lots of money, no…

a wise activist once said -- it takes an immediate crisis to move the needle in public action

Re: A study on the extent of global air pollution

#62

Post by AstralStorm »

cmews wrote: post #49
rladd wrote: post #48

Earlier quoted context omitted.

> portable masks with safe air to breath temporary when you are outside With regard to PM2.5, that already exists and is called an N95 mask.

Unfortunately those masks are not protecting you against gases and vapours like sulphur dioxide, nitrogen dioxide, ozone, and carbon monoxide which do impact asthmatic people a lot or are the cause of developing asthma.

Well, a mask with an activated carbon filter actually does, to an extent, except for carbon monoxide.

(There are other more specialized filters that are more effective against SOx and NOx too, but carbon is also good against VOC.)

Re: A study on the extent of global air pollution

#63

Post by magicalist »

jamiecurle wrote: post #53
easytiger wrote: post #22

Earlier quoted context omitted.

And how do they square the circle that with the deindustrialisation and move to central heating that those particulates production are at a century low in many western countries yet seem to be more deadly than ever.

This is what I cannot fathom. I was born the 70's, played outside for all my childhood amidst all the leaded petrol and sulphur dioxide, I handled leaded petrol for a job at a petrol station for solid three years and I lived in dense urban town from childhood until today. Everything seems to be way lower than it ever has been: [1]: https://www.gov.uk/government/statistics/emissions-of-air-po... [2]: https://www.gov.u…

Explicitly mentioned:

"Moreover, the study revealed that while daily levels of PM2.5 have reduced in Europe and North America over the past two decades..."

Re: A study on the extent of global air pollution

#64

Post by AstralStorm »

jjk166 wrote: post #57
trgn wrote: post #21

Earlier quoted context omitted.

This is the battered spouse argument in our relationship to our living environment. Well of course the air is unhealthy, but see, you need to understand the whole story! Categorical thinking is not always because of a lack of nuance or of zealotry or stupidity (which are generally more modern dismissive interpretations). Delineating categories is a useful framing to firmly separate what is on the one hand good and vi…

No it's not, and the comparison is absurd. With domestic violence it is trivially easy to have none at all, and there is a very distinct difference between none and some. With air quality there is a smooth and continuous measurement for what is in the air. You will never get to zero particulates per cubic meter, you can only get under a certain level. Further, the effects of air quality are also a smooth continuous f…

Binary categorization is quite appropriate, considering there are IDLH levels. And it is actually highly nonlinear for most contaminants. There's an area of none to low risk, even chronic, then an area of exponentially increasing risk, then area where the levels are known to be harmful chronically, and yet another where they're immediately dangerous.

So while not binary, the difference between dangerous and not is usually pretty sharp.

For PM 2.5, 35 ug/m3 is considered harmful after just few hours. For chronic exposure, mean levels of years is considered safe. (There is probably some level that is certain to produce silicosis in about everyone. I would have to dig on that.) That is how thin the margin is. And these are the laxer NIOSH values.

Even AQI which is weighted to be more linear and granular, easily gets pegged at moderate (risky to sensitive people) in clean seeming cities unless there's wind... (That is a level above 15 ug/m3 already by some.)

Re: A study on the extent of global air pollution

#65

Post by graeme »

gniv wrote: post #58
graeme wrote: post #18

Earlier quoted context omitted.

* Testing/replacing car air filter * Any mask outside. Even surgical can cut more than half of pm 2.5 * A lot of people recommending indoor filters, but indoor pollution generally a lot less than outdoors except when cooking. You can verify this with a PM 2.5 monitor. I do recommend indoor filters, but if budget is limited and you're working on overall lower pm 2.5 filters, testing car and getting masks is the more e…

> indoor pollution generally a lot less than outdoors Why would that be? Unless you have central A/C with good filter, I don't see how indoor air would be cleaner.

Couldn't say. If I had to guess, a lot of ventilation happens through walls which act as a filter. Even window screens likely do.

Regardless of reason, my AQI will regularly be 4-13 indoors when it is 38-54 outside, even if I have windows open.

Note that this only covers PM 2.5, and not other stuff such as VOCs etc.

Re: A study on the extent of global air pollution

#66

Post by schiffern »

cmews wrote: post #31

My wife has severe astma and when traveling this is something that worries me all the time. At home we have blue air machines and plants to filter the air, but astma attacks still happen (when she didn't use her medicines enough) when she travels from work to home on bad air quality days in Amsterdam. The astma medication is something that comes with a lot of trade-offs/health complications if you use it too much. Ho…

>Unfortunately I can't create this kind of machine (software eng, no hardware skills), but I think there is a very big market for portable masks with safe air

You may not need to DIY (much).

I recently posted my experiences and tips with the AirPro mask,[0] and the response was at least entertaining! Tl;dr it's a wearable HEPA device that pipes 99.97% filtered air into any N95 mask. Besides improved filtration, this also prevents the hot humid mask feeling that some people dislike.

You might consider adding a carbon prefilter (look for sheet filter medium and cut to size) for the HEPA unit, and pairing that with a carbon N95 mask (eg 3M 8247). This should filter several pollutants of concern you mentioned, including nitrogen oxides, sulfur oxides, and ammonia. Sadly CO is nearly impossible to filter.

For indoor filtration, you might find some MERV-13 filters[1] and make a Corsi Box[2]. No engineering skill required, just a bit of duct tape.

Maybe something here will help! Cheers and good health

[0] https://news.ycombinator.com/item?id=34378478

[1] https://news.ycombinator.com/item?id=34797981

[2] https://cleanaircrew.org/box-fan-filters/

Re: A study on the extent of global air pollution

#67

Post by cmews »

schiffern wrote: post #66
cmews wrote: post #31

My wife has severe astma and when traveling this is something that worries me all the time. At home we have blue air machines and plants to filter the air, but astma attacks still happen (when she didn't use her medicines enough) when she travels from work to home on bad air quality days in Amsterdam. The astma medication is something that comes with a lot of trade-offs/health complications if you use it too much. Ho…

>Unfortunately I can't create this kind of machine (software eng, no hardware skills), but I think there is a very big market for portable masks with safe air You may not need to DIY (much). I recently posted my experiences and tips with the AirPro mask,[0] and the response was at least entertaining! Tl;dr it's a wearable HEPA device that pipes 99.97% filtered air into any N95 mask. Besides improved filtration, this…

This comment made my day! I'm going to give it a try and will convince my wife to test it to see if it helps :)

Re: A study on the extent of global air pollution

#68

Post by Tade0 »

runnerup wrote: post #39
Tade0 wrote: post #32

Earlier quoted context omitted.

I live in an area that has harmful amounts on PM2.5 during the winter(80ug/m3+, double that a few days of the year). You'll need an air filter, but not just any other one - it has to be oversized for the living space and spin up at a low threshold - air filters commonly only actually start when the measurements indicate more than 25ug/m3. Also nice if it has an ionizer - my experience is that it generally increases e…

> Also nice if it has an ionizer I'd be concerned that the ionizers generate trace ozone. Am I wrong about this?

They do - no way around it which I would know of.

I only experienced a whiff of ozone when I returned home after two weeks, with the device on all this time.

Personally I only ever feel the irritating effect of elevated PM levels, so I keep the ionizer on.

I definitely cough much less during a cold now, having the purifier, than before purchasing it.

Re: A study on the extent of global air pollution

#69

Post by schiffern »

cmews wrote: post #67
schiffern wrote: post #66

Earlier quoted context omitted.

>Unfortunately I can't create this kind of machine (software eng, no hardware skills), but I think there is a very big market for portable masks with safe air You may not need to DIY (much). I recently posted my experiences and tips with the AirPro mask,[0] and the response was at least entertaining! Tl;dr it's a wearable HEPA device that pipes 99.97% filtered air into any N95 mask. Besides improved filtration, this…

This comment made my day! I'm going to give it a try and will convince my wife to test it to see if it helps :)

Glad to hear it. :)

A couple tips I forgot, some of which may increase the all-important "wife acceptability coefficient":

- carbon tends to get saturated pretty quick, so in regular use I would replace the (cheaper) prefilter at least weekly, mask every 2-3 weeks

- testing may show you can get away with a non-carbon N95 and just the carbon prefilter; cheaper and the look may be found more acceptable

- carbon will immediately start adsorbing pollutants from ambient air, so keep all unused carbon in a sealed jar or sealed original packaging

- have fun with it! At Starbucks and pizza places I'm either Mr Snuffleupagus or Discount Darth Vader :D

- Corsi Boxes can be loud, so I use Low if people are around (High only for unoccupied space); shrouding or draping with fluffy towels can help too (hint: not the good towels)

- if you have forced air HVAC you might start out just using a MERV-13 filter in there; I prefer Filtrete 1900, but in general anything with many pleats = low pressure drop is better; most HVAC is not rated for large pressure drops across the filter

- I've had good success making an experimental "Carbon Corsi", taping two cheap 20x20 filters together with ~2 lb of replaceable aquarium carbon in the middle (change every ~two months) and taping that on top; this filters gaseous pollutants in the home, and can further muffle the box fan

(sorry, I swear this list was two items long when I started...)

Hope she can find some relief via your mutual efforts! Severe asthma can feel almost like a prison, so it's important to be extra kind and patient. Best of luck you guys

Post reply on HN