I haven't, but my brother has many times in the last ten years. He told me in Beijing, Shanghai and Guangzhou, you NEVER get clear air days where you can clearly see the blue sky, and people regularly wear very thick face masks in order to protect their breathing as best they could. Indeed, during 75th Anniversary parade in Beijing of the founding of the People's Republic of China, they had to shut down all the coal-fired power plants in and near Beijing for a week just to get that clear air for the day of the parade.
That's why I felt the Paris climate accord should have included a provision that China must phase out most coal-fired power plants (or impose EPA-style emission controls on them) over the next ten years. The emissions from coal-fired power plants is so bad that it's affecting the air quality of the Korean Peninsula and Japan's home islands (especially during the spring when the Asian Dust dust storms carry all that pollution downwind, and you can easily see the pollution in Pyongyang, Seoul, most Japanese cities, and the pollution can travel as far as the US West Coast).
I live in Guangzhou, I can assure you the sky is blue and people are quite healthy. Beijing is another matter, but bear in mind you see the few days a year it is super bad. Also what you're saying is exactly why the accord was set up, pollution effects the world not just where it came from, and everyone agreed that this is a bad thing not just for the environment but for international cooperation.
In terms of having any provision in there, it would have been impossible to get every nation on earth to agree to it. That's why each country set their own targets, and most are beating it and driving further greener progress. That's why the accord is such an important first step in achieving that goal, it was never meant to be the end of.
Coal is a very bad source of energy, that's why everywhere on earth is closing that chapter and moving to green energy. Trump isn't going to bring back any coal jobs and the US will have to move to greener energy sources, which is why it doesn't make much sense to pull out.
Currently the accord is set up so if you can afford to move to expensive green energy, do. If you can't, the global fund that wealthier nations pay into will help the poorer nations to transition. As all the wealthy countries have already polluted and gone through that transition before, it's a bit rich to expect a poor nation to suddenly jump an energy step and be condemned for using the cheaper sources. Hence they can use money from this fund, and as the wealthier nations are generally more technologically advanced, they will be buying that technology from the nations that funded it. Making the setup rather net-neutral.
Basically the whole situation is just very confusing. Every nation on earth agreed to this, except for one man. Maybe if it was called the 'Trump Accord' he wouldn't be so hostile towards it, but he seems to not be able to understand the depths of things whilst doing a very poor job at explaining his motives. Like if it's the money that's an issue then just stop paying it, the US only pledged about 0.01% of their GDP into the fund so it was never a huge amount. That's like you giving a single cent to a homeless person.
Who knows at this point, trying to understand Trump logic requires access to an alternate reality that the rest of the world just doesn't have access to.