A recent study by scientists at Montreal’s McGill university has found unusually high concentrations of potentially harmful airborne aerosols containing nanoparticles around Montreal’s Trudeau airport. Some contained chromium and arsenic. The study, published in December 2018 in the prestigious journal “Environmental Pollution” found these observations were statistically higher than corresponding measurements in downtown Montreal and at major highways during rush hour. The airport is thus a hotspot for nanoparticles containing “emerging contaminants” (substances produced by human activities that have, or are suspected to have, adverse ecological and/or human health effects.) The study found trends in levels of nanoparticles during the day showed concentrations that exhibited peaks during times with many flights, also showing correlations with pollutants (CO, NOx, and O3) – confirming the anthropogenic source of the aerosols. The nanoparticles, especially containing heavy metals, are potentially a matter of public health. The study detected up to 2 million particles per cubic centimetre of air, which is more than the amount found so far at other airports. More studies need to be carried out, as health is at stake.