Assessment of the Epidemiological Data Relating Lung Cancer to Air Pollution

Abstract

The epidemiological data linking air pollution and lung cancer are derived from statistical associations concerning rates of cancer among urban and rural residents, migrant studies and studies of occupational groups exposed to effluents from fossil fuel combinations. Few, if any of these studies, are adequately adjusted for both relatively simple measures of cigarette smoking or the potentially more subtle effects of the duration of smoking. Because urbanization and industrial sources of air pollution correspond chronologically with the major increases in cigarette smoking, it is not likely that the specific attributable risk to each component can be adequately assessed. Interactions between cigarette smoking and specific air pollutants, similar to those seen between cigarette smoking and asbestos and or radiation, may be occurring. Considering the various estimates made over the last 25 years, it is likely that the effect of air pollution on lung cancer is something greater than zero; however, it is unlikely that the estimate exceeds 2% of all lung cancers or 5/100,000 cases in urban males. Thus, the effect on all cancers is likely to be less than 1% of all cases.

Genotoxic and mutagenic activity of environmental air samples in Flanders, Belgium

“…Epidemiological studies, carried out to investigate the health risk related to air pollution, suggest that ambient air pollution may be responsible for increased rates of lung cancer [1,2,3]. Particulate matter with a mean diameter less then 10 µm (PM10), is associated with adverse health effects including increased respiratory problems, cancer and mortality [4].…”

Consensus report: mutagenicity and carcinogenicity of car exhausts and coal combustion emissions

“…However, epidemiological data have not been sufficient to allow a precise determination of the quantitative association between specific exposure and cancer risk (3,4). …”

Contribution of Organic Particulates to Respiratory Cancer

“…Speizer recently reviewed the evidence relating lung cancer risks and outdoor air pollution (4). His review again emphasized studies that attempt to explain differences between lung cancer mortality or incidence in urban and rural settings based on variation in air pollution.…”

“…The report notes that, while outdoor pollutants have markedly decreased over the last 20 years, there are still local areas with higher contamination levels and changing patterns both in the type and the dispersion of pollutants. There are also unanswered questions about the interrelationship of outdoor air pollutants and personal risk factors such as smoking and indoor exposures as well as quantification of the contribution of particulates and other pollutants to the risk of cancer (4,10,11). Such precise information would allow us to assess the risk of cancer based on specific exposures.…”