Quantifying primary and secondary source contributions to ultrafine particles in the UK urban background

Total particle number (TNC, ≥7 nm diameter), particulate matter (PM 2.5 ), equivalent black carbon (eBC) and gaseous pollutants (NO, NO 2 , NOx, O 3 , CO) have been measured at an urban background site in Leicester over two years (2014 and 2015). A derived chemical climatology for the pollutants showed maximum concentrations for all pollutants during the cold period except O 3 which peaked during spring. Quantification of primary and secondary sources of ultrafine particles (UFPs) was undertaken using eBC as a tracer for the primary particle number concentration in the Leicester urban area. At the urban background site, which is influenced by fresh vehicle exhaust emissions, TNC was segregated into two components, TNC = N1 + N2. The component N1 represents components directly emitted as particles and compounds which nucleate immediately after emission. The component N2 represents the particles formed during the dilution and cooling of vehicle exhaust emissions and by in situ new particle formation (NPF). The values of highest N1 (49%) were recorded during the morning rush hours (07:00–09:00 h), correlating with NOx, while the maximum contribution of N2 to TNC was found at midday (11:00–14:00 h), at around 62%, correlated with O 3 . Generally, the percentage of N2 (57%) was greater than the percentage of N1 (43%) for all days at the AURN site over the period of the study. For the first time the impact of wind speed and direction on N1 and N2 was explored. The overall data analysis shows that there are two major sources contributing to TNC in Leicester: primary sources (traffic emissions) and secondary sources, with the majority of particles being of secondary origin

Lung deposited surface area in Leicester urban background site/UK: Sources and contribution of new particle formation

Lung Deposited Surface Area (LDSA) has been identified as a potential metric for the correlation of a physical aerosol particle properties with health outcomes. Currently, there is little urban LDSA data. As a case study, we investigated measurements of LDSA (alveolar) concentrations in a mid-size European city. LDSA and associated measurements were carried out over 1.5 years at an urban background site in Leicester, UK. Average LDSA concentrations in the cold (November–April) and warm (May–October) seasons of UK were 37 and 23 μm2 cm−3, respectively. LDSA correlates well (R2 = 0.65–0.7, r = 0.77–0.8) with traffic related pollutants, such as equivalent black carbon (eBC) and NOX. We also report for the first time in the UK the correlation between an empirically derived LDSA and eBC. Furthermore, the effect of wind speed and direction on the LDSA was explored. Higher LDSA concentrations are observed at low wind speeds (1–2 m s−1), owing to local traffic emissions. In addition, the diurnal variation of LDSA showed a second peak in the afternoon under warm and relatively clean atmospheric conditions, which can be attributed to photochemical new particle formation (NPF) and growth into the Aitken mode range. These NPF events increased the average background LDSA concentrations from 15.5 to 35.5 μm2 cm−3, although they might not be health-relevant. Overall, the results support the notion that local traffic emissions are a major contributor to observed LDSA concentrations with a clear seasonal pattern with higher values during winter

Essential medicines containing ethanol elevate blood acetaldehyde concentrations in neonates

Neonates administered ethanol-containing medicines are potentially at risk of dose-dependent injury through exposure to ethanol and its metabolite, acetaldehyde. Here, we determine blood ethanol and acetaldehyde concentrations in 49 preterm infants (median birth weight = 1190 g) dosed with iron or furosemide, medicines that contain different amounts of ethanol, and in 11 control group infants (median birth weight = 1920 g) who were not on any medications. Median ethanol concentrations in neonates administered iron or furosemide were 0.33 (range = 0–4.92) mg/L, 0.39 (range = 0–72.77) mg/L and in control group infants were 0.15 (range = 0.03–5.4) mg/L. Median acetaldehyde concentrations in neonates administered iron or furosemide were 0.16 (range = 0–8.89) mg/L, 0.21 (range = 0–2.43) mg/L and in control group infants were 0.01 (range = 0–0.14) mg/L. There was no discernible relationship between blood ethanol or acetaldehyde concentrations and time after medication dose. Conclusion: Although infants dosed with iron or furosemide had low blood ethanol concentrations, blood acetaldehyde concentrations were consistent with moderate alcohol exposure. The data suggest the need to account for the effects of acetaldehyde in the benefit-risk analysis of administering ethanol-containing medicines to neonates

Evaluation of biomass burning across North West Europe and its impact on air quality

Atmospheric particulate pollution is a significant problem across the EU and there is concern that there may be an increasing contribution from biomass burning, driven by rising fuel prices and an increased interest in the use of renewable energy sources. This study was carried out to assess current levels of biomass burning and the contribution to total PM10 across five sites in North-West Europe; an area which is frequently affected by poor air quality. Biomass burning was quantified by the determination of levoglucosan concentrations from PM10 aerosol filters collected over a 14 month period in 2013/2014 and continued for a further 12 months at the UK site in Leicester. Levoglucosan levels indicated a distinct period of increased biomass combustion between November and March. Within this period monthly average concentrations ranged between 23 ± 9.7 and 283 ± 163 ng/m3, with Lille showing consistently higher levels than the sites in Belgium, the Netherlands and the UK. The estimated contribution to PM10 was, as expected, highest in the winter season where the season average percentage contribution was lowest in Wijk aan Zee at 2.7 ± 1.4% and again highest in Lille at 11.6 ± 3.8%, with a PM10 mass concentration from biomass that ranged from 0.56 μg/m3 in Leicester to 2.08 μg/m3 in Lille. Overall there was poor correlation between the levoglucosan concentrations measured at the different sites indicating that normally biomass burning would only affect atmospheric particulate pollution in the local area; however, there was evidence that extreme burning events such as the Easter fires traditionally held in parts of North-West Europe can have far wider ranging effects on air quality. Network validation measurements were also taken using a mobile monitoring station which visited the fixed sites to carry out concurrent collections of aerosol filters; the result of which demonstrated the reliability of both PM10 and levoglucosan measurements