> “Our findings emphasise that exercise remains beneficial even in polluted environments,” lead researcher Professor Po-Wen Ku said in a statement. [...] “We don’t want to discourage people from exercising outdoors,” said Co-author Professor Paola Zaninotto.
The health effects of exercise outdoors are combined from two effects:
- Positive effects due to exercise. These start out strong but level off after a while.
- Negative effects due to pollution. These increase almost linearly with time spent outside.
One might ask, is there an amount of daily exercise at which the negative effects overpower the positive ones? Yes, in a handful of cities around the world, after a few hours of exercise, the pollution makes additional outdoors exercise actually harmful.
But almost everywhere a marginal minute of exercise provides a positive effect on health regardless of time already spent exercising, and there is nowhere in the world where something like an hour of exercise a day is a net negative. Get out there. Pick an active means of commuting (cycling, running, walking, skiing, rollerblading, skateboarding, unicycling) and don't worry so much about pollution unless you live in one of those single-digit cities which I forget where they are, but probably concentrated in Asia.
(I feel bad about typing this out without linking to the source. I'm looking for it in my notes!)
There are lots of places in the world that exceed 35μg/m^3 PM2.5, and quite a few that exceed 50μg/m^3 PM2.5 regularly - the entire SF Bay Area is over 35 right now. Los Angeles and San Diego are both above 50 right now, as are huge swaths of Eastern Europe, Africa, and Asia... it’s a bit more than just a few handful of cities. Exercising near wildfires can be quite unhealthy too. There are places in the world where exercising outdoors is harmful to your health, but most of that is self-regulating.
The other thing to note from the paper is that even the range of 0 to 10 μg/m^3 of PM2.5 causes a 30% decrease in the benefits of exercise. That’s a pretty big reduction of benefits from exercise for the EPA’s “Good” category of air. It’s still a net positive, so you should still exercise, but just a little pollution has pretty big measurable negative effects.
Active commuting is great, you get exercise, and help reduce pollution at the same time. Even if exercise in polluted areas is beneficial, we also definitely need to keep raising awareness and improving air quality, for the time spent not exercising, for people with athsma and heart disease, for the people who can’t and/or don’t exercise. We should worry about it a little, while we exercise. ;)
But a 10x ratio on the same road is also plausible if the Google car is following a large truck on one pass and then driving by itself on the second.
I have a Phillips air purifier which includes a sensor for particles - whenever Diesel cars drove by the particles spiked and it went full throttle for a while if I had my window open.
Trump has outright said he's pro fossil fuels and his policy choice shows it. If there was a proposal to ban or limit EVs in the US, I would not at all be surprised. These people do not care about you or me or all, just their pocket linings.
China and India look rough though.
https://map.purpleair.com/air-quality-raw-pm25
Localized phenomena like a neighbor starting a fire, up to the activity of nearby factories and power plants, up to national and global phenomena like wildfires and weather patterns, all have dramatic effects. Looking at an air quality map once and determining that you don’t have to think about air quality because you’re in the US is a mistake.
Exercise outdoors is a wonderful thing, obviously, but there are some days, even in the US, where you might think twice or even consider shifting your exercise to a different (less-polluted) time of the day.
Summer evenings at home in my small Ohio village are often a health hazard, a polluted nightmare driven by the perverse compulsive ignition of so-called 'recreational' yard fires by pyromaniac neighbors.
If it is an Ozone Action day and/or a Heat Advisory day, it is near certain that one or more of the Don't Tread On Me jamokes who live nearby will come out of their houses at sunset, pile a bunch of garbage into a 55-gallon drum or a circle of rocks, sprinkle with accelerant, toss a match and back away. Eyes glazed, they'll watch for a minute, then go back inside, sometimes coming back out every ten minutes or so to refuel the fire, other times letting it blaze until the original pile is down to embers. In any case, there is a new plume of local smoke to add to the day's irritants.
It is a startling phenom to observe, let alone endure. The behavior is made all the more crazy, imho, by the presence of children. These are parents, asserting their rights to burn, and teaching their children to Live Free Or Die. It seems to me to be driven by a rebelliousness, part of the anti-woke wave, country-fried counter-culture, as in "I got your global warming right here, pard".
It's like, listening to country music stations and realizing how many (most!) contemporary and historical Country songs are themed around alcohol-worship.
But I digress.
I apologise. I was triggered by the mention of 'localized phenomena' and the horrified realization that so many of my fellow citizens are self-destructive cray-cray.
and then next decade smartwatches
Once EVERYONE starts seeing air-quality on their phones every hour of the day everywhere they are, they will start to care and then eventually, maybe do something about the politics to improve air-quality
Imagine the game-changer if air-quality was in the next iPhone
They already make sensors that can go on a keyring so inside a phone is not implausible within a few years
I've been advocating for closed windows and increased use of air purifiers and FFP3/N99 respirators, and had some limited success among people I know. People are often easily convinced once they see the state of their filter or respirator after a few days of use.
Put it this way, although cars are allegedly better than they were, fuel consumption hasn't dropped considerably. The cars are more numerous than ever, and, although there are EVs, there are still more ICE cars than there were in the good old days when petrol came with lead in it.
I am not sure that most people in urban areas even know what good air tastes and smells like. I take a canal path through lush countryside, far from any cars for most of the way. This canal has an aqueduct (or is it a viaduct?) over a motorway and the contrast is incredible. You go from basically smelling flowers to air pollution and back to clean air again quite quickly, so the filth is totally noticeable. Note the cars on the motorway are going at speed, so they should be working efficiently (until a few decades ago 56 mph was what engines were optimised for regarding efficiency in the UK).
If just living in a major city then you don't get this instant switch from bad to good air. So you just don't notice it. If you could see the filth, you would prefer a swimming pool that was pissed in, it is that toxic.
If you do have to live in a city, my top tip is to find out if there are any meteorologists in town. If there are, buy a house next to where they are living. Anecdotal, however, I used to work with meteorologists and they would always live to the West of the city centre, to get cleaner air than those living in the east of the city, or further downwind.
Again anecdotal, however, due to the canal and motorway experience described above, in post-industrial countries such as the UK, it is definitely the vehicles rather than any other source. Given the choice of microparticles that just get in your blood or clumps of big particles that you can eventually cough up and spit out, I would much prefer the latter. My hunch is that the legislation to improve vehicle emissions has optimised the exhaust for nanoparticles. Please prove me wrong!
https://www.london.gov.uk/programmes-strategies/environment-...
The main takeaway is that yes, urban air quality (including fine particulate matter) has improved massively over time, but most of it had little to do with road traffic, as for decades it wasn't a significant contributor to the overall mix. The important change was the move away from burning solid fuels like coal for household heating and in power stations within cities, to using gas and electricity with larger, out-of-town power stations.
As other sources have declined, road traffic has indeed become the largest contribution to urban air pollution, but even here there has been progress. Fine particulate emissions have continued to decline as car manufacturers have adapted to more stringent regulation (cheating scandals notwithstanding). A bigger problem now is higher non-exhaust emissions caused by larger and heavier vehicles. This is something else that will need to be solved via regulation. Other policies like Low Traffic Neighbourhoods can also help to restrict the worst pollution to major roads and away from where most people live.
Urban air quality is never going to be as good as that in the countryside, but it's not true to believe that no progress has been made, and that it's simply been a switch in the type of pollution.
I run air filters in my apartment throughout winter months, which tend to be the worst in terms of air quality here.
When I go outside in the morning I can really smell the stuff in the air, for a brief moment, until I get used to it. But you definitely notice the difference!
Lots of particles cars emit are from tires and break pads. I think someone was measuring that but I don’t have sources but most likely I read that somewhere in the comments of HN.
The industrial-revolution era mill owners were very aware of this too. Posh area of Manchester is to the south (westerly winds;) Leeds to the north (mix of northerly and westerly winds I believe).
Also, anecdotally, smaller towns and villages can have poor air quality too due to log burners. They're an absolute pain. You can tell when an area has become gentrified when shiny new chimneys start popping up or a log burner shop opens up!
Tires get more efficient every year, dust has reduced as the companies compete to make them last longer, and we're finally seeing the tire industry respond to pressure to reduce toxic runoff. Michelin's been removing phenols, for instance: https://resicare.michelin.com/news/michelin-resicare-resin-1...
Of course if you burn trash none of that matters, but it's already illegal in pretty much any advanced societies.
FWIW, I think - based on not feeling my throat close up most of the time - that the number of people who do this is small.
The old oven remained though, and was used as a self-emptying trash can. When it filled up, a fire was lit to empty it. I don't remember what the sorting rules were (I assume "does it burn well and not smell up the apartment too badly when lighting it") and how common plastic packaging was back then, but I'm sure that the emissions coming out from the chimney were not a concern.
facts that read as curse to be found on an amuelet dug up in some near(ish) future iteration of whatever the,, it is,, that we are doing right now
This is one the main reasons why I would prefer working remote, it is hard to utilize this time well (for exercise) if you are in the office.
At least with PM you can wear a mask, although I am still searching for the best one that works during intense exercise.
Also wanted to point out "Trump EPA moves to abandon rule that sets tough standards for deadly soot pollution"
https://apnews.com/article/epa-soot-air-pollution-trump-zeld...
Try a professional mask, like 3M 7500 with 2138 filters.