Do air quality targets really represent safe limits for lung cancer risk?

Area of Science:

• Environmental Health
• Toxicology
• Public Health

Background:

• Traditional air quality targets rely on particle mass concentration, overlooking ultrafine particles (UFPs).
• This oversight may lead to inadequate protection against lung cancer risks from airborne pollutants like polycyclic aromatic hydrocarbons and heavy metals.

Purpose of the Study:

• To assess the adequacy of current air quality targets in protecting the Italian non-smoking population from lung cancer.
• To evaluate the cancer risk contribution of both sub-micron (including UFPs) and super-micron particles.

Main Methods:

• Application of a modified risk-assessment scheme.
• Estimation of cancer risk from different particle size fractions.
• Evaluation of three mitigation scenarios: chemical reduction, local ventilation, and improved indoor air quality via mechanical ventilation.

Main Results:

• A very high lung cancer risk was identified, primarily driven by UFPs, particularly within indoor environments.
• Even with advanced mitigation strategies, the estimated lifetime cancer risk for the Italian population exceeded the maximum tolerable level (1x10⁻⁵).

Conclusions:

• Current air quality metrics are insufficient for protecting against particle-induced lung cancer risk.
• Enhanced indoor air quality management, including mechanical ventilation and control of indoor sources, is crucial.
• Further research and policy revisions are needed to address the risks posed by UFPs.