Chemical characterisation of particulate matter in urban transport modes

Traffic is a main source of air pollutants in urban areas and consequently daily peak exposures tend to occur during commuting.Personal exposure to particulate matter(PM)was monitored while cycling and travelling by bus,car and metro along an assigned route in Lisbon(Portugal),focusing on PM_(2.5) and PM_(1)0(PM with aerodynamic diameter<2.5 and 10μm,respectively)mass concentrations and their chemical composition.In vehicles,the indoor-outdoor interplay was also evaluated.The PM_(2.5) mean concentrations were 28±5,31±9,34±9 and 38±21μg/m 3 for bus,bicycle,car and metro modes,respectively.Black carbon concentrations when travelling by car were 1.4 to 2.0 times higher than in the other transport modes due to the closer proximity to exhaust emissions.There are marked differences in PM chemical composition depending on transport mode.In particular,Fe was the most abundant component of metro PM,derived from abrasion of rail-wheel-brake interfaces.Enhanced concentrations of Zn and Cu in cars and buses were related with brake and tyre wear particles,which can penetrate into the vehicles.In the motorised transport modes,Fe,Zn,Cu,Ni and K were correlated,evidencing their common traffic-related source.On average,the highest inhaled dose of PM_(2.5) was observed while cycling(55μg),and the lowest in car travels(17μg).Cyclists inhaled higher doses of PM_(2.5) due to both higher inhalation rates and longer journey times,with a clear enrichment in mineral elements.The presented results evidence the importance of considering the transport mode in exposure assessment studies.

Industrial and wildfire aerosol pollution over world heritage Lake Baikal

Lake Baikal is the biggest reservoir of fresh water with unique flora and fauna;presently it is negatively affected by climate change, water warming, industrial emissions, shipping,touristic activities, and Siberian forest fires.The assessment of air pollution-related Baikal’s ecosystem damage is an unsolved problem.Ship, based expedition exploring the Baikal atmospheric aerosol loading, was performed over the lake area in July 2018.We combine the aerosol near-water and vertical distributions over the Lake Baikal basin with meteorological observations and air mass transportation simulations.Lidar sounding of aerosol fields in the troposphere assesses the atmospheric background in the pristine areas and the pollution during fire-affected periods.Aerosol optical properties(scattering and spectral absorption) converted to the particle number size, black carbon(BC) mass, and Absorption Angstrom Exponent(AAE) provide the inside into aerosol characterization.Transport of industrial emissions from Krasnoyarsk and Irkutsk regions, and wildfire plumes from Republic of Yakutia relates the pollution sources to the increased concentrations of fine particle numbers, PM_(10) and BC mass over Southern and Northern/Central Baikal, respectively.The highest PM10 and BC are associated to the harbor and touristic areas of intensive shipping and residential biomass burning.Deposition estimates applied to aerosol data exhibit the pollution fluxes to water surface over the whole Baikal area.AAE marks the impact of coal combustion, residential biomass burning, and wildfires indicating the high pollution level of the Lake Baikal ecological system.