Beijing felt cool and crisp in late October.
With a light jacket, you could wander through falling yellow leaves for hours cutting between quiet gray hutongs and bright, busy streets full of bars plying dark beer and real cocktails.
The weather, as I understood it, could not have been better and yet the city's smart, lovely residents couldn't stop apologizing for it.
It took a minute to realize they were talking about pollution—particularly the 2.5-micron-sized hunks of heavy metal floating into our lungs, past our alveoli and into our blood like tiny truants bum rushing a city bus.
Foreign scientists have described the impact of Beijing's climate on the city's plants as tantamount to nuclear winter; some of China's own have deemed the city unfit for human beings.
But there were human beings there. Great ones. Tens of millions of them, eating and drinking and talking in ways that rival life in any great city in the world.
Only the few longtime expats I encountered truly griped about the air, usually while puffing away on Chinese cigarettes. Like most in Beijing, they took no steps to stave off early death—they didn't wear bicycle helmets, motorcycle helmets or any sort of face mask.
But some did in spades.
I ate a lunch of dumplings and grilled lamb in the cloistered air of the diplomatic apartment belonging to an American correspondent at a major US newspaper who cancelled our plans to meet at a restaurant due to the weather.
After our talk, I spent the afternoon picking out Americans on the street by their impressive efforts to not breathe the local air.
The game hit its pinnacle when I watched a renowned energy expert -- in town for an energy conference--eat an entire multi-course meal while a device hooked to his belt pumped clean air through a hose strapped to his nose.
Soon enough, I began to regard my own 3M mask like a big green glob of zinc oxide—the sort of thing white people wear to forewarn locals about our propensity to whinge.
Sure, I thought, the air tastes vaguely of burning plastic. Sure, laser pointers function here work more like light sabers.
But, hey, we're all gonna go one way or another.
Might as well do it with a belly full of dumplings and cocktails.
By the end of my second day, I stopped wearing a mask on the train. By the end of the week, I'd wadded it into the deepest corner of my backpack.
It felt like the right thing to do; imagine going everywhere in Seattle in a thick yellow slicker.
In a way, I came to like the way Beijing's bad weather added drama to life.
Many talked about the six-day holiday the government created to clear the air for the Asia Pacific Economic Cooperation (APEC) summit.
Indeed, I found Beijing's pollution operated on the psyche much like snow does—building into a soul-crushing soup all week and then disappearing one fine morning to reveal skies so blue you're suddenly happy to be alive.
I spent that day marching through wild persimmon orchards, yellow forests and abandoned quarries on the municipal outskirts with the Beijing Hikers --who bravely trek no matter what the PM2.5 concentration.
“What a place!” I couldn't help thinking.
That said, I was happy to get back in balmy Saigon, until I started actually looking at the data on the difference between our “weather.”
This year, Vietnam's air quality ranked among the ten worst in the world, making it hard to imagine what will happen when China eventually dumps all its high-energy, low-yield industries to pursue energy efficiency and renewables.
As I write this, scores of export factories are being built in the industrial parks outside Ho Chi Minh City to dye fabric and make zippers as we prepare to inherit the garment and shoe industry China no longer wants.
More export-oriented industries are expected to follow, particularly if the Trans Pacific Partnership passes.
Everyone seems so excited about the prospect of becoming America's new factory.
But I'm sure not, particularly given Vietnam's energy strategy—or lack thereof.
Emission-free hydropower yields will decline as the government pursues a vague plan to run the country on more dirty coal and a handful of Russian-built nuclear plants.
Information on renewables is notoriously vague and incorrect—so much so that Vietnam appears to have all but given up on wind power projects.
What's more, as poorly-designed public transit projects drag on, a series of Free Trade Agreements will soon inject more cars onto the city's already crowded, filthy roadways.
I imagine these ideas are unlikely to result in anything but a hotter, wetter version of Beijing's bad weather.