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Air quality reporting on iOS

intergalactic.systems

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Re: Air quality reporting on iOS

#71

Post by moritzwarhier »

mfer wrote: post #59
sandworm101 wrote: post #46

>> I noticed something strange in the iOS weather app: The air quality index seems to be defined relative to the country from which one accesses the air quality map. Yup. And if you look closely the underlying map also sometimes changes based on which country one is standing in (Crimea/Taiwan). Services like iOS are not scientific but consumer and government-focused services. They exist to appease a host of intereste…

Who defines what is “good” air quality in a dispassionate way? Or any of the other levels. If they just showed numbers without colors, how would the UX work for the general public who isn’t all that knowledgeable? Building a useful [1] experience while dealing with groups who read things differently isn’t easy and it’s not going to lead to global consistency because people are diverse and inconsistent [1] https://www…

Maybe the WHO?

If the air makes people sick is a pretty objectively quantifiable question.

The differences go beyond unit conversion and a main issue is how much we are used to tolerate people dying early or having seriously reduced quality of their lives because of pollution.

Especially in urban and industrial areas.

What adds to the complexity is that air quality can vary significantly within a city. Compare having a flat between two busy roads and a nice house in the suburbs.

And compare that flat between two busy roads to a room next to a factory in the global south, or the US, or in Europe.

It's a question of how many suicides, cancers, strokes etc we want to tolerate.

There are studies quantifying the effects of these "local differences". And they are easy to find.

To me, pretending this was a question of culture or genetics is malicious obfuscation of the actual issues - not accusing you personally, but this is the essence of the combination of many of the comments here.

Air quality is measurable using several objective categories of pollutants.

Standardizing the units is one issue, facing the reality of millions of casualties per year is another one.

Re: Air quality reporting on iOS

#72

Post by rkapsoro »

Yeah, I've noticed this too.

It looks like the air quality models that iOS Weather is using are integrated into a single system, and then that system is asked to render maps in any of the different regions' AQI systems.

Which means, as OP has observed, if you open the map from one region, and then navigate the map viewer to another region, you can see how the AQI scoring system from the first region would evaluate the second. Which is rather interesting.

Also fwiw I've reckoned that these AQI models are clearly highly algorithmic, extrapolating and synthesizing data where sensors are not available.

Re: Air quality reporting on iOS

#73

Post by thebruce87m »

crazygringo wrote: post #61
brookst wrote: post #51

Earlier quoted context omitted.

Many products have multiple stakeholders. I can't think of a single product that exists "to render dispassionate information" and nothing else.

Really not sure what your point is? The temperature and humidity values that iOS Weather reports are objective and "dispassionate", no? Likewise wind speed and so forth? AQI is unique in this case, in that it is a color-coded interpretation of combining multiple underlying objective values (PM2.5, etc.). And different governments have chosen different official national schemes for this, according to what they want th…

The way things are going I’m sure there will be some questioning the temperature and humidity values and how we really know if they are true or not.

Re: Air quality reporting on iOS

#74

Post by crazygringo »

counters wrote: post #62
crazygringo wrote: post #52

Earlier quoted context omitted.

Not just forecasting, but reporting values right now . Spatial interpolation is much more non-obvious than you might initially assume, when the data points are coming from arbitrary locations and not a regular grid. For anyone curious, here [1] is a good place to start, or look up "Kriging interpolation". The basic implementation of any kind of continuous temperature estimation is to have a generic equation that rela…

Eh, kriging is overkill relative to the skill you end up with since fine-grain spatial variability in weather can arise from a lot more than the static factors you can pull into such a scheme. This is why objective analysis techniques are typically preferred. More importantly, high-resolution priors are universally available from weather models, so there is no need to just to ever naively interpolate between weather…

I'm curious if you could expand -- I researched this a while ago but what I'm describing is as deep as I got from various online tutorials.

What kind of objective analysis techniques? And where does someone get high-resolution priors from? Are you saying that companies have gone out and done a one-time mapping of temperature etc. at a e.g. 1-mile grid across the US? (Which would be over 3 million points at that scale, compared to the ~10,000 US weather stations?)

Re: Air quality reporting on iOS

#75

Post by crazygringo »

thebruce87m wrote: post #73
crazygringo wrote: post #61

Earlier quoted context omitted.

Really not sure what your point is? The temperature and humidity values that iOS Weather reports are objective and "dispassionate", no? Likewise wind speed and so forth? AQI is unique in this case, in that it is a color-coded interpretation of combining multiple underlying objective values (PM2.5, etc.). And different governments have chosen different official national schemes for this, according to what they want th…

The way things are going I’m sure there will be some questioning the temperature and humidity values and how we really know if they are true or not.

As long as we can buy thermometers and hygrometers to verify with our own eyes, I don't think too many people will be questioning them.

And as long as ice continues to freeze at 32°F and water continues to boil at 212°F, I don't think anybody will be questioning the accuracy of the thermometers they buy.

Re: Air quality reporting on iOS

#76

Post by [deleted] »

Havoc wrote: post #7

I mean tech is full of conflicting standards. (see relevant xkcd...) In this particular case the actual values just happen to land on the edge of two colours in the scales with very different connotations - orange vs green.

[deleted]

Re: Air quality reporting on iOS

#77

Post by calsy »

nullindividual wrote: post #63
908B64B197 wrote: post #58

Earlier quoted context omitted.

> what my local government/news says about air quality That's assuming the local government is giving the truth regarding air quality and that their "official scale" is made to reflect reality and not obscure some measurements.

Let's not go there. Unsubstantiated conspiracy theories do not add to this discussion.

Unlike basic weather metrics like temperature, humidity etc. Air quality measurements are directly impacted by human activity and are extremely contentious.

In my hometown, there is a fight between locals and waste operators over excessive burn offs. The validity of air quality readings from the area are being tested in court.

In the past, the Vietnamese government removed IQAir from the App Store and Google Play as citizens became increasingly concerned about the air quality in the capital cities.

You wont learn much if you label everything you don't understand a 'conspiracy theory'. Air quality is not just another weather measurement.

Re: Air quality reporting on iOS

#78

Post by 908B64B197 »

counters wrote: post #64

The problem here is twofold. First, many countries have their own laws and policies regarding air quality exposure. Often times these regulations use metrics about time-average exposure (e.g. the annual average 8-hr maximum ozone concentration) and can't trivially be converted between agencies. It causes very negative user experiences when your air quality summary disagrees with what a regulatory agency is putting ou…

> many countries have their own laws and policies regarding air quality exposure. Often times these regulations use metrics about time-average exposure (e.g. the annual average 8-hr maximum ozone concentration) and can't trivially be converted between agencies. It causes very negative user experiences when your air quality summary disagrees with what a regulatory agency is putting out to the public due to a measurement technicality

Ultimately, why not simply compute it and give the user a warning that the local measurement isn't compatible with proper AQI measurement?

Also, does my body magically changes the way it reacts to air pollution as soon as I take my first step abroad?

Re: Air quality reporting on iOS

#80

Post by mistercheph »

crazygringo wrote: post #61
brookst wrote: post #51

Earlier quoted context omitted.

Many products have multiple stakeholders. I can't think of a single product that exists "to render dispassionate information" and nothing else.

Really not sure what your point is? The temperature and humidity values that iOS Weather reports are objective and "dispassionate", no? Likewise wind speed and so forth? AQI is unique in this case, in that it is a color-coded interpretation of combining multiple underlying objective values (PM2.5, etc.). And different governments have chosen different official national schemes for this, according to what they want th…

No, they are neither objective nor dispassionate, despite being grounded in empirical data and methods.

Factors like building shade, vehicle density, wind cover, terrain, cloud coverage, and variations in humidity, mean that thermometers placed at different points in any selected area will report massive variations in temperature, and the naive (and impossible) approach of even distributions of identical sensors taking measurements at the same clock times placed across some given weather area will yield numbers that are not helpful for most people.

For example, about 1/3 of the area of Burbank, CA is recreation and park spaces that are in the verdugo mountains, at their highest point within Burbank limits 1800 ft. above sea level, and with almost zero residents. The other 2/3 of Burbank are about 600 ft. above sea level. How would you offer a number that summarized the weather in Burbank?

Imagine factoring time into this. There is no temperature of the hour, there are individual measurements taken at specific moments in time in specific places, using differing methodologies, different equipment, variations in MoE, and at varying frequencies. Put all this together, and the work of the observational meteorologist to produce daily or hourly temperature averages becomes extremely complicated, and the first question they would ask is, "What will the averages be used for?"

Here are some examples from the large literature on these problems:

https://www.tandfonline.com/doi/full/10.1080/07055900.2015.1...

https://www.sciencedirect.com/science/article/abs/pii/S00221...

https://link.springer.com/chapter/10.1007/978-1-935704-35-5_...

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