Even relatively low quantities of air pollution increase the risk of premature death, according to an article in Thorax.
The study involved more than 5,000 adults divided into four groups. Each group was monitored over a period of 16 years beginning in 1966 to 1970 and ending between 1994 and 1998.
Even though air pollution decreased during the study period, the researchers found that the risk of premature death was still there, even at comparatively low levels. Respiratory illnesses appear to be the most common cause of death.
Premature death risk from respiratory disease rose by almost 4% per 10 ug/m3 increase in black smoke. For every increase of 10 parts per billion in sulfur dioxide during the 1982 to 1998 period the risk of early death went up 13%.
Even after adjusting for social deprivation, lifestyle, and other contributing factors, the numbers still stood. The findings "point to continuing public health risks even at the relatively low levels of black smoke and sulfur dioxide that now occur."