Evaluating size-fractioned indoor particulate matter in an urban hospital in Iran.

Hospitals host vulnerable people with potentially enhanced sensitivity to air pollutants. We measured particulate matter (PM) including PM1, PM2.5, and PM10 with a portable device in a hospital, a nearby reference building, and ambient air in Shiraz, Iran. Indoor/outdoor (I/O) ratio values were calculated to infer on the origin of size-fractioned PM. The mean hospital indoor concentrations of PM2.5 and PM10 (4.7 and 38.7 µg/m3, respectively) but not PM1 were higher than in the reference building and lower than in ambient air. The highest hospital PM10 mean concentrations were found in the radiotherapy ward (77.5 µg/m3) and radiology ward (70.4 µg/m3) while the lowest were found in the bone marrow transplantation (BMT) ward (18.5 µg/m3) and cardiac surgery ward (19.8 µg/m3). The highest PM2.5 concentrations were found in the radiology (8.7 µg/m3) and orthopaedic wards (7.7 µg/m3) while the lowest were found in the BMT ward (2.8 µg/m3) and cardiac surgery ward (2.8 µg/m3). The I/O ratios and the timing of peak concentrations during the day (7 a.m. to 4 p.m.) indicated the main roles of outdoor air and human activity on the indoor levels. These suggest the need for mechanical ventilation with PM control for a better indoor air quality (IAQ) in the hospital.

Characterization of particles emitted by pizzerias burning wood and briquettes: a case study at Sao Paulo, Brazil.

The burning of biomass in pizza ovens can be an important source of air pollution. Fine particulate matter represents one of the most aggressive pollutants to human health, besides the potential to interfere with global radiative balance. A study in real-world condition was performed in three pizzerias in São Paulo city. Two of the pizzerias used eucalyptus timber logs and one used wooden briquettes. The results from the three pizzerias revealed high average concentrations of PM2.5: 6171.2 µg/m3 at the exit of the chimney and 68.2 µg/m3 in indoor areas. The burning of briquette revealed lower concentrations of PM2.5. BC represented approximately 20% and 30% of the PM2.5 mass concentration in indoor and at chimney exhaust, respectively. Among the trace elements, potassium, chlorine and sulphur were the most prevalent in terms of concentration. Scanning electron microscopy (SEM) analysis revealed particles with an individual and spherical morphology, i.e. the conglomeration of spherical particles, flattened particles in the formation of fibres, the overlapping of layers and the clustering of particles with sponge-like qualities. The average emission factors for PM2.5 and BC due to the burning of logs were 0.38 g/kg and 0.23 g/kg, respectively. The total emissions of PM2.5 and BC were 116.73 t/year and 70.65 t/year, respectively, in the burning of timber logs.

Heavy truck restrictions and air quality implications in São Paulo, Brazil.

This study quantified the effects of traffic restrictions on diesel fuel heavy vehicles (HVs) on the air quality of the Bandeirantes corridor using hourly data obtained by continuous monitoring of traffic and air quality at sites located on this avenue. The study addressed the air quality of a city impacted by vehicular emissions and that PM10 and NOX concentrations are mainly due to diesel burning. Data collection was split into two time periods, a period of no traffic constraint on HVs (Nov 2008 and 2009) and a period of constraint (Nov 2010, 2011 and 2012). We found that pollutants on this corridor, mainly PM10 and NOX, decreased significantly during the period from 2008 to 2012 (28 and 43%, 15.8 and 86.9 ppb) as a direct consequence of HV traffic restrictions (a 72% reduction). Rebound effects in the form of increased traffic of light vehicles (LVs) during this time had impacts on the concentration levels, explaining the differences between rates of reduction in HV traffic and pollutants. Reductions in the number of trucks resulted in longer travel times and increased traffic congestion as a consequence of the modal shift towards LVs. We found that a 51% decrease in PM10 (28.8 µg m-3) was due to a reduction in HV traffic (vehicle emissions were estimated to be 71% of total sources, 40.1 µg m-3). This percentage was partially offset by 10% more PM10 emissions related to an increase in LV traffic, while other causes, such as climatic conditions, contributed to a 13% increase in PM10 concentrations. The relationships analyzed in this research served to highlight the need to apply urban transport policies aimed at decreasing pollutant concentrations in São Paulo, especially in heavily congested urban corridors on working days.