Long-term exposure to smog is deadly, even at low levels

Seoul traffic in the summer: yum, lots of ozone and particulates here.

Well, isn't that just wonderful. I think those of us living in large cities already felt to a certain extent that living in a place with such bad air just can't be good for you in the long term, and another study has shown this to be true. In fact, the first person quoted in the article is able to tell too:

Lorraine LeBlanc, whose lungs are already damaged by disease, can tell when air pollution levels are high without even looking outside -- her breathing becomes even more strained.

"I get worried," she tells CTV News. "I know it's going to make my lungs worse and that's something I don't need. They're bad enough as it is."

and:

The study out of the U.S. found that people who lived in areas with the highest concentrations of ground-level ozone had a 25 to 30 per cent greater annual risk of dying from respiratory diseases compared with people from area with the lowest levels of the pollutant.

Ground-level ozone forms when nitrogen dioxide from car tailpipes, coal-fired power plants and other industries collides with oxygen in the presence of sunlight.

It's different from fine particulate matter, the tiny particles of pollutants emitted by factories, cars, and power plants. That element of air pollution tends to be more concentrated at its source.

Ground-level ozone, on the other hand, can be found in higher concentration in suburbs and rural areas downwind of cities, because ozone takes time to form as it travels along the wind.

and the most important part:

The researchers estimate that the risk of dying from respiratory diseases, such as emphysema, pneumonia and chronic obstructive pulmonary disease, rises four per cent for every 10 parts-per-billion increase in exposure to ozone.

It would be nice if articles like this also had information or links to sites with information on what those of us living in the city can do about this in the short term. A site here has some information on the beneficial effects of filters and house plants (the latter seems to be pretty limited, but I would question this as plants have a psychological effect that also contributes to overall health):

Article Living filter: do houseplants really improve indoor air? includes:
former EPA Indoor Air Division Director Robert Axelrad's primary complaint. He said that NASA's studies did little to simulate the air changes of a typical home or office. "Our calculations indicate that a much higher density of plants would be required (hundred of plants in the typical house) to achieve these results," writes Exelrad.

At "Indoor Air Pollution: An Introduction for Health Professionals", learn:
As a practical means of pollution control, the plant removal mechanisms appear to be inconsequential compared to common ventilation and air exchange rates. In other words, the ability of plants to actually improve indoor air quality is limited in comparison with provision of adequate ventilation.

Edit March 22: at long last, the answer!