On cancer risk estimation of urban air pollution

Abstract

The usefulness of data from various sources for a cancer risk estimation of urban air pollution is discussed. Considering the irreversibility of initiations, a multiplicative model is preferred for solid tumors. As has been concluded for exposure to ionizing radiation, the multiplicative model, in comparison with the additive model, predicts a relatively larger number of cases at high ages, with enhanced underestimation of risks by short follow-up times in disease-epidemiological studies. For related reasons, the extrapolation of risk from animal tests on the basis of daily absorbed dose per kilogram body weight or per square meter surface area without considering differences in life span may lead to an underestimation, and agreements with epidemiologically determined values may be fortuitous. Considering these possibilities, the most likely lifetime risks of cancer death at the average exposure levels in Sweden were estimated for certain pollution fractions or indicator compounds in urban air. The risks amount to approximately 50 deaths per 100,000 for inhaled particulate organic material (POM), with a contribution from ingested POM about three times larger, and alkenes, and butadiene cause 20 deaths, respectively, per 100,000 individuals. Also, benzene and formaldehyde are expected to be associated with considerable risk increments. Comparative potency methods were applied for POM and alkenes. Due to incompleteness of the list of compounds considered and the uncertainties of the above estimates, the total risk calculation from urban air has not been attempted here. -Environ Health Perspect 102(Suppl 4): 173-181 (1994).

Specific volatile hydrocarbons in smoke from oxidative pyrolysis of softwood pellets

“…The contribution to photooxidant formation in the summer season is low because of low emissions of ethene and propene as the most important ozone precursors [16] in the smoke. The four most significant hydrocarbons with respect to health hazards are ethene, propene, benzene and 1,3-butadiene [17] which are emitted from burning of all solid biomass fuels [9] but only in very small amounts from wood pellets.…”

Single Pollutant Versus Surrogate Measure Approaches: Do Single Pollutant Risk Assessments Underestimate the Impact of Air Pollution on Lung Cancer Risk?

“…Furthermore, in Sweden particulate organic material was estimated to cause 0.7 cancer cases per 100,000 person years, and exposure to 1,3-butadiene was associated with 0.31 cases per 100,000 person years. 4 A recent unit risk-based assessment in California 9 yielded an average of 0.43 cancer cases per 100,000 person years attributable to air pollution, with particulate organic material and 1,3-butadiene providing the largest contribution.…”

“…2 In the last years the use of "unit risks" as potency factors has been established in cancer risk assessment studies. [3][4][5][6][7][8][9] The unit risk factor describes the cancer risk associated with lifelong exposure to 1 g/m 3 of the substance of interest, assuming a linear dose-response function without a threshold value. 10 Unit risk factors for a variety of substances were evaluated and published by the International Agency for Research on Cancer (IARC), the United States Environmental Protection Agency (USEPA), the Office of Environmental Health Hazard Assessment, California (OEEHA), and the Länder-ausschuss fü r Immissionsschutz, Nordrhein-Westfalen, Germany (LAI).…”

Mutagenicity and pah‐analysis of airborne particulate matter in rural site of central Taiwan, Sha‐Lu

“…Some epidemiological studies show a positive correlation between air pollution and human lung cancer [10][11][12][13][14].…”