High levels of pollution from vehicle exhaust fumes and other types of fuel combustion are closely linked to excess deaths due to pneumonia, say researchers.
In the research, scientists from Birmingham University studied atmospheric emissions in England for the period 1996-2004 and attributed some 4,000 extra pneumonia deaths each year to engine pollution.
The study reports a "strong correlation" between high levels of pollution and the deaths of thousands of people in England.
In total, 390,000 people died of pneumonia during the eight years examined. Researcher also linked pollution to higher rates of some cancers, chronic obstructive pulmonary disease (COPD) and rheumatic heart disease.
Further analysis, allowing for the effects of the social factors, showed that pneumonia deaths were strongly and independently linked to emissions, with the exception of sulphur dioxide from coal burning.
The primary culprits were emissions associated with oil combustion, including vehicle exhaust fumes.
During the eight years of the study there were almost 390.000 deaths from pneumonia.
"Total annual losses as a result of air pollution probably approach those of the 1952 London smog," the British Medical Journal quoted the study's author, as saying.
Because the links were so strong across all categories of exposure and deaths were so much higher than would be expected, this suggests that these pollutants directly damage lung tissue, the author said.
The study is published in the Journal of Epidemiology and Community Health.