Living in Hong Kong air pollution is something that we always have to deal with (especially in winter). The wind/weather conditions are much worse for pollution here in winter and cooler temps also don’t help.
There are an abundance of apps here for keeping track throughout the day and some of them have global aqi info (e.g. Air Matters).
I am personally pretty risk averse when it comes to running in mucky air. Ours isn’t from the same source as US/Canada so I can’t compare apples to apples but I generally don’t go out if it is anything more than “yellow” on the US scale (moderate).
One thing that is also interesting is how all the different air quality indices are different. The index used by HK govt prioritizes short term health effects which basically means ozone is heavily weighted over pm2.5 which is much more a long term health issue. If you ever have the unpleasant experience of running in high ozone you will likely be at home afterwards wondering what that burning is in your chest (yuck). Ozone is much more likely to put some people in the hospital so the HK index is skewed to that. I generally look at the US index and primarily pm2.5 and pm10 but will also check ozone first. Ozone is nearly always worse later in the day when it’s really sunny.
We don’t tend to get months on end of non-stop terrible air and so I make do with gyms and indoor bikes as a stop gap. We generally have sep to March as the worst months but it is not like every day is bad and mornings are usually better. I also have a number of high end air purifiers and AQi Meters in my home so I know what the indoor air quality is. I don’t know about in US but most indoor commercial buildings here seem to have very good air filtration. I have taken one of my meters to the gym and seen that the air was very good.
But yes, if you don’t have any filtration and you have leaky windows and doors the indoor air quality will be surprisingly bad. It’s amazing how much just coming and going through the front door of the apt messes it up on a bad day.
One thing that is worth pointing out is that indoor meters are pretty useless outdoors and not accurate but, unless your burning food in your apt at the time, if your indoor quality is bad then it’s likely that the outdoor is as bad or worse.
I feel like I am very cautious compared to others I know here though. It’s not that I have an sensitivities it’s just that I don’t think any of it is good for you and due to the volumes of time outside that we do you are talking significantly more exposure than average person.
I have tried running in different pollution masks (and I think they work to a degree) but they are mostly difficult to keep fitted correctly if your sweating etc. I have used an “Airinum” mask a bit if there is a reason I really want to go outside but usually I just feel like it’s more enjoyable/less hassle to make do with the gym and indoor stuff rather than try to do a long one wearing a mask. I actually purposely bought a cheap bike and a good turbo trainer primarily to give me a way to do indoor workouts at home when it’s bad. I know biking isn’t a great transfer to running but I don’t have space for a treadmill and being able to do something is better than nothing if we get a block of bad days.
It is definitely super frustrating when you have been training well and your long weekend workouts get scuppered by pollution.
