High concentrations of cadmium, cerium and lanthanum in indoor air due to environmental tobacco smoke

Background Environmental tobacco smoke (ETS) is one of the most important sources for indoor air pollution and a substantial threat to human health, but data on the concentrations of the trace metals cerium (Ce) and lanthanum (La) in context with ETS exposure are scarce. Therefore the aim of our study was to quantify Ce and La concentrations in indoor air with high ETS load. Methods In two subsequent investigations Ce, La and cadmium (Cd) in 3 smokersʹ (11 samples) and 7 non-smokersʹ (28 samples) households as well as in 28 hospitality venues in Southern Germany were analysed. Active sampling of indoor air was conducted continuously for seven days in every season in the smokersʹ and non-smokersʹ residences, and for 4 h during the main visiting hours in the hospitality venues (restaurants, pubs, and discotheques). Results In terms of residences median levels of Cd were 0.1 ng/m3 for non-smokersʹ and 0.8 ng/m3 for smokersʹ households. Median concentrations of Ce were 0.4 ng/m3 and 9.6 ng/m3, and median concentrations of La were 0.2 ng/m3 and 5.9 ng/m3 for non-smokersʹ and for smokersʹ households, respectively. In the different types of hospitality venues median levels ranged from 2.6 to 9.7 ng/m3 for Cd, from 18.5 to 50.0 ng/m3 for Ce and from 10.6 to 23.0 ng/m3 for La with highest median levels in discotheques. Conclusions The high concentrations of Ce and La found in ETS enriched indoor air of smokersʹ households and hospitality venues are an important finding as Ce and La are associated with adverse health effects and data on this issue are scarce. Further research on their toxicological, human and public health consequences is urgently required