Different approaches to explore the impact of COVID-19 lockdowns on carbonaceous aerosols at a European rural background site.

To prevent the fast spread of COVID-19, worldwide restrictions have been put in place, leading to a reduction in emissions from most anthropogenic sources. In this study, the impact of COVID-19 lockdowns on elemental (EC) and organic (OC) carbon was explored at a European rural background site combining different approaches: - "Horizontal approach (HA)" consists of comparing concentrations of pollutants measured at 4 m a.g.l. during pre-COVID period (2017-2019) to those measured during COVID period (2020-2021); - "Vertical approach (VA)" consists of inspecting the relationship between OC and EC measured at 4 m and those on top (230 m) of a 250 m-tall tower in Czech Republic. The HA showed that the lockdowns did not systematically result in lower concentrations of both carbonaceous fractions unlike NO2 (25 to 36 % lower) and SO2 (10 to 45 % lower). EC was generally lower during the lockdowns (up to 35 %), likely attributed to the traffic restrictions whereas increased OC (up to 50 %) could be attributed to enhanced emissions from the domestic heating and biomass burning during this stay-home period, but also to the enhanced concentration of SOC (up to 98 %). EC and OC were generally higher at 4 m suggesting a greater influence of local sources near the surface. Interestingly, the VA revealed a significantly enhanced correlation between EC and OC measured at 4 m and those at 230 m (R values up to 0.88 and 0.70 during lockdown 1 and 2, respectively), suggesting a stronger influence of aged and long distance transported aerosols during the lockdowns. This study reveals that lockdowns did not necessarily affect aerosol absolute concentrations but it certainly influenced their vertical distribution. Therefore, analyzing the vertical distribution can allow a better characterization of aerosol properties and sources at rural background sites, especially during a period of significantly reduced human activities.

Parabens and antimicrobial compounds in conventional and "green" personal care products.

The personal care product (PCP) industry is a worldwide multi-billion-dollar industry. Several synthetic compounds like parabens and antimicrobial agents triclosan (TCS) and triclocarban (TCC) are ingredients in many PCPs. Due to growing public awareness of potential risks associated with parabens and other synthetic compounds, more PCPs are being marketed as "green," "alternative," or "natural." We analyzed 19 green and 34 conventional PCP products obtained from a European store for seven parabens, TCC, and TCS. We found no statistically significant difference in the concentrations between green and conventional products. Only four products mentioned parabens in the list of ingredients; however, parabens were detected in 43 products, and at µg/g levels in seven PCPs. Methylparaben was typically present at the highest concentration, and one mascara exceeded the European legal concentration limit of methylparaben. Low concentrations of isopropyl-, isobutyl-, and benzylparabens, which are banned in the EU, were detected in 70% of PCPs. The cumulative estimated daily intake of parabens is an order of magnitude higher for people using only conventional products than those using green products exclusively. We propose that legislation be developed with more explicit rules on when a product can be advertised as "green" to aid consumers' choices.