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Comment by hammock | Hacker News Reader

The US-wide heat map aligns pretty well with agricultural and industrial pollution, not necessarily wildfires. Let's not turn every last thing into a climate change debate.

A US-wide view also obscures the air quality where it matters most, which is population centers. They are too small to show up on the blurry, smoothed heat map provided. In population centers (big cities), smog from personal and commercial vehicles is the primary contributor to poor air quality.

I spent Thanksgiving week on Catalina Island and I personally watched the smog roll over greater Los Angeles. However on Thanksgiving Day I woke up and looked east, and the air was incredibly clear like I've never seen. On Friday morning it was still pretty good. But by Saturday the smog was back to normal. The weather was the same all week - this had to do with the number of vehicles on the road in a given day.

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> The US-wide heat map aligns pretty well with agricultural and industrial pollution, not necessarily wildfires.

That's not a map of pollution, it's a map of satellite measured smoke plumes. I also completely disagree that it aligns well with agricultural and industrial pollution. Northern Nevada and Montana have hardly anything going on and you would expect the Imperial Valley to be deep red.

Yeah, air pollution is a related but not identical issue to climate change. Emissions from ICE vehicles affect both air quality and atmospheric CO2. Particulates from tire wear (for example) affect primarily local air quality and not atmospheric CO2.

And even setting aside climate change, we should also be worried about all the pollution we're breathing in. Lots of health issues there.

Before all of the emissions regulations were imposed, I remember in the 80’s growing up in LA county, a “Smog Alert” could be issued for the day, warning us to limit exercise time outdoors.

Heh kids these days do NOT know how bad LA used to be. Pictures don't really do it justice, you had to be there.

https://www.insider.com/vintage-photos-los-angeles-smog-poll...

Of course, tire wear is greater on electric vehicles, owing to their greater mass. Cars in general are bad for air quality, EV are not really an improvement compared to mass transit.

So higher tire wear, zero emissions in the city. EVs are a step change in air pollution in the city - I whole heartedly disagree. Looks like we need to work on better tire technology as well (they cause a lot of problems in the local runoff of water).

> Looks like we need to work on better tire technology as well

Yes, and also discourage private car use in general in the city in favor of less polluting alternatives. Cities are where mass transit and cycling are most viable as alternatives to driving and where the effects of air pollution from driving are most pronounced.

https://www.washington.edu/news/2020/12/03/tire-related-chem...

very interesting read for people curious -- one way that tire wear pollution is causing problems

Fascinating. And good science. Thanks for sharing

Particulate pollution can also cause cooling that masks the overall warming trend.

https://e360.yale.edu/features/air-pollutions-upside-a-brake...

it's important to differentiate though. climate change is largely mediopolitically-driven narrative playing into the aims of the fossil fuel industry to delay action (e.g., carbon pricing). pollution is a concrete, immediate issue that kills millions of people annually. we should be attacking pollution like a freight train, not CO₂, which is a gas that's essential to life on earth.

that would mean getting rid of coal, oil and gas as a first, and biggest, and maybe even only, step. we could have already been solving this issue if we hadn't stopped allowing nuclear to be built in the 90's, as in, we could be completely coal free by now and on the road to eliminating gas in our electricity infrastructure. then as grid-scale storage is developed over the next few decades, we could move steadily over to solar and wind over the next century (for both electricity and transportation) as the nuclear plants go out of commission at the end of their 50-70 year lifecycle.

the climate change narrative is amorphous and far in the future, so it's easy to deflect criticism and solutions. not so much with pollution, which has been a problem for over a century already. care deeply and fiercely about pollution, not CO₂.

It happens because of LA geography which allows smog to become trapped.

https://www.latimes.com/california/story/2021-11-11/how-an-i...

I feel the conclusion that vehicles are responsible for this is not the only explanation. I live in LA area and on Thanksgiving Day there were strong Santa Ana winds. Usually those winds bring dry air and have good strength to push out all of the air particles giving a clear view. I have noticed the visibility is less when it is more humid compared to dry and also when the air is pushed away with some winds. Agree air quality is not the best but also not worse either and better than I assume what it used to be.

I don’t have any objections to focusing on polluters other than wildfires, but as someone who lives in a place where “dramatic” feels too much an understatement when describing the impact of the severity, frequency, and longevity of wildfires and their smoke over recent years… it’s not really up for debate. This is a real, significant climate change impact, and it’s devastating for air quality. It may very well be and stay highly localized, but that’s totally consistent with climate change predictions: different local climates of course will experience different local changes.

But it’s not turning anything into a climate change debate to recognize that some places which used to seldom or never have serious impact to air quality from wildfires but now quite do. It’s definitely a change in climate (hotter, drier weather over longer periods) that leads to longer, more severe fire seasons. And they’re definitely happening… again, even if just in some locales.

There are multiple different forms of air pollution in smog. The two biggest one is Nitrogen oxide and Sulfur oxide, with personal and commercial vehicles being responsible for around 50% of the nitrogen oxide.

Sulfur oxide comes from homes being heated by oil, coal plants burning coal, chemical industries, and boat traffic.

After those two main components there are secondary pollutants like ozone, smoke (primarily from burning wood) and other particulates.

So simplified one can say that cars and trucks are responsible for half of slightly less then half the picture, but naturally ratios can differ depending on the exact environment.

> The weather was the same all week - this had to do with the number of vehicles on the road in a given day.

The Santa Ana Winds [0] were blowing very strong right up until Thursday afternoon according to weather reports [1].

But regarding air quality, a lot of the particulate matter in the air in LA is blown in from the desert. Due to the mountainous geography east of LA, there's a corridor leading up from the Gulf of California over the Salton Sea funneling right into LA. The Salton Sea is an ecological disaster created by farm run off that's drying up. As such there's a lot of toxic pollutants in the dry lake bed that are picked up by those winds creating toxic dust clouds that get blown right into LA.

[0] https://en.wikipedia.org/wiki/Santa_Ana_winds

[1] https://www.foxla.com/news/santa-ana-winds-thanksgiving-2022

Maintaining high levels of atmospheric pollution is crucial to curb short-term global warming.

Without pollution earth may warm 0.5C and more within a year or so.

https://www.sciencealert.com/air-pollution-cools-climate-mor...

We had strong Santa Ana winds on Thanksgiving in LA, which blows the pollution out because they come from the East instead of the West.

Car traffic doesn't make that much daily difference.

This sounds like the right explanation. Thanksgiving traffic can't be that much less than other days - plenty of people are still traveling and even working. Wind patterns vary a lot more day to day than car traffic.

> The US-wide heat map aligns pretty well with agricultural and industrial pollution, not necessarily wildfires. Let's not turn every last thing into a climate change debate.

Does agricultural and industrial pollution not contribute to climate change?

Pollutants contribute to short-lived cooling:

https://www.sciencealert.com/air-pollution-cools-climate-mor...

You can sometimes see the smog above NYC on a clear summer day driving from Connecticut (on the Merritt Parkway IIRC). At least, I've seen it once.

You can really tell how much is in the air here after it rains - and the first few weeks of the Covid quarantine! - it's absolutely magnificent when the air is clean.

> it's absolutely magnificent when the air is clean.

Yes, absolutely. The changes in the views in the LA basin after a good rainfall are stunning, especially taken from the hills. After a month or so of life in the smog, the sudden visibility is amazing! But then, day-by-day, the smog gradually builds back up again. It's perceptible. The only silver lining may be that the smog is what makes the sunsets so amazing.

What colour was the smog?

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