Release of ultrafine particles from three simulated building processes

Abstract

10Building activities are recognised to produce coarse particulate matter but less is 11 known about the release of airborne ultrafine particles (UFPs; those below 100 nm 12 in diameter). For the first time, this study has investigated the release of particles 13 in the 5-560 nm range from three simulated building activities: the crushing of 14 concrete cubes, the demolition of old concrete slabs, and the recycling of concrete 15 debris. A fast response differential mobility spectrometer (Cambustion DMS50) 16 was used to measure particle number concentrations (PNC) and size distributions 17(PNDs) at a sampling frequency of 10 Hz in a confined laboratory room providing 18 controlled environment and near-steady background PNCs. The sampling point 19 was intentionally kept close to the test samples so that the release of new UFPs 20 during these simulated processes can be quantified. Tri-modal particle size 21distributions were recorded for all cases, demonstrating different peak diameters 22 in fresh nuclei (<10 nm), nucleation (10-30 nm) and accumulation (30-300 nm) 23 modes for individual activities. The measured background size distributions 24showed modal peaks at about 13 and 49 nm with average background PNCs 25 ~1.4710 4 cm -3 . These background modal peaks shifted towards the larger sizes 26 during the work periods (i.e. actual experiments) and the total PNCs increased 27 between 2 and 17 times over the background PNCs for different activities. After 28 adjusting for background concentrations, the net release of PNCs during cube 29 crushing, slab demolition, and "dry" and "wet" recycling events were measured as 30 ~0.77, 19.1, 22.7 and 1.76 (×10 4 ) cm -3 , respectively. The PNDs were converted 31 into particle mass concentrations (PMCs). While majority of new PNC release 32 was below 100 nm (i.e. UFPs), the bulk of new PMC emissions were constituted 33 by the particles over 100 nm; ~95, 79, 73 and 90% of total PNCs, and ~71, 92, 93 34 and 91% of total PMCs, for cube crushing, slab demolition, dry recycling and wet 35 recycling, respectively. The results of this study firmly elucidate the release of 36UFPs and raise a need for further detailed studies and designing health and safety 37 related exposure guidelines for laboratory workplaces and operational building 38 sites. 39

Recycling concrete: An undiscovered source of ultrafine particles

“…, resulting in a rise of over 17-times the background values. The concentrations measured in this study were found to be in agreement with our previous findings (Kumar et al, 2012c) where the total PNCs during the dry recycling process were found to be ~2.51 10 5 cm -3…”

“…Knowledge of size-resolved PNDs is essential for accurately estimating the deposition doses in the respiratory region (i.e. sum of alveolar, tracheobronchial and extrathoracis regions), which can occur as a result of exposure to airborne particles during recycling events (Kumar et al, 2012c). Average size-resolved PNDs measured at each sampling location were used, together with size-resolved deposited efficiency, as proposed by the ICRP model (ICRP, 1994).…”

Physicochemical characteristics and occupational exposure to coarse, fine and ultrafine particles during building refurbishment activities

“…It may be the case that the attrition between the surfaces of equipment and building materials during high rotational frequency have produced precursor gases, however, further investigations are clearly needed to reach to a clear consensus. The average values of PNCs during our general demolition activity at refurbishment site were ~2-times lower than those reported by Kumar et al (2012c) during simulation of slab demolition in the laboratory. Furthermore, our results of average PNCs during the drilling activity (5.22 ± 4.44 ×10 4 cm -3 ) was ~5-times lower compared with laboratory studies of Azarmi et al (2014).…”

Nanoparticle emissions from 11 non-vehicle exhaust sources – A review

“…The PNCs below 100 nm size were found to be increased to about 1.6 times during demolition compared with the background PNCs. A recent study by Kumar et al (2012c) investigated the release of particle number and size distributions in the 5-560 nm range from the three simulated building activities: the crushing of concrete cubes, the demolition of old concrete slabs, and the recycling of concrete debris. The measurements were taken in a controlled laboratory environment, at about 0.15 m away from the samples since the aim was to investigate the emission rates of nanoparticles.…”

“…We are referring here the NES to the sources other than the tailpipe exhausts of ground vehicles. A number of NES are the focus of this article (see justification in Section 2), including particles arising from road-tyre interaction, brake wear and resuspension (Dahl et al, 2006;Mathissen et al, 2011), industrial emissions such as from power plants (Li et al, 2009), idling, taxiing and take-off from aircraft at airports (Hu et al, 2009;Mazaheri et al, 2009), ship emissions from ports or harbours (Saxe and Larsen, 2004), construction, demolition and processing of concrete (Hansen et al, 2008;Kumar et al, 2012c), residential and commercial cooking (Buonanno et al, 2009b;Buonanno et al, 2010), domestic biomass burning (Hosseini et al, 2010), forest fires and burning of agriculture residue (Reid et al, 2005), municipal waste incineration (Buonanno et al, 2009a), cigarette smoking , and secondary formation .…”