Nicotine dynamics in an indoor environment can be greatly affected by building parameters (e.g. relative humidity (RH), air exchange rate (AER), and presence of ozone), as well as surface parameters (e.g. surface area (SA) and polarity). To better understand the indoor fate of nicotine, these parameter effects on its sorption, desorption, and oxidation rates were investigated on model indoor surfaces that included fabrics, wallboard paper, and wood materials. Nicotine sorption under dry conditions was enhanced by higher SA and higher polarity of the substrate. Interestingly, nicotine sorption to cotton and nylon was facilitated by increased RH, while sorption to polyester was hindered by it. Desorption was affected by RH, AER, and surface type. Heterogeneous nicotine-ozone reaction was investigated by Fourier transform infrared spectrometry with attenuated total reflection (FTIR-ATR), and revealed a pseudo first-order surface reaction rate of 0.035 +/- 0.015 min(-1) (at [O(3)] = 6 +/- 0.3 x 10(15) molecules cm(-3)) that was partially inhibited at high RH. Extrapolation to a lower ozone level ([O(3)] = 42 ppb) showed oxidation on the order of 10(-5) min(-1) corresponding to a half-life of 1 week. In addition, similar surface products were identified in dry and high RH using gas chromatography-mass spectrometry (GC-MS). However, FTIR analysis revealed different product spectra for these conditions, suggesting additional unidentified products and association with surface water. Knowing the indoor fate of condensed and gas phase nicotine and its oxidation products will provide a better understanding of nicotine's impact on personal exposures as well as overall indoor air quality.

Sleeping microenvironment (SME), is characterized by higher temperature, humidity, and CO2 concentration. Emission of Volatile Organic Compounds (VOC) in SME is important considering the long duration people spend there with high proximity between their respiration inlets and potential emission sources, such as bedding material. This study concentrates on the influence of SME conditions on VOC emissions from polyurethane mattresses, and provides first approximation for inhalation exposure during sleep, based on measured emissions. Eight types of polyurethane mattresses were tested in a parallel continues-flow chamber system, to compare between VOC emission under different temperature, relative humidity, and CO2 concentrations. Contribution of mattress covers to emission fluxes was also examined. Eighteen VOCs were quantified with fluxes ranging from 10–4 to 10–1 mg/(h·m–2). Under sleeping conditions VOC emissions increased significantly. Elevated heat seems to be the major contributor to the enhanced emissions, compared to elevated relative humidity and CO2 concentration. Exposure levels estimated for sleeping child/infant indicate that SME can be a significant contributor to VOC exposure, yielding concerning exposure levels for few compounds. Furthermore, the present study demonstrates the strong dependency of sleeping person exposure on air exchange rate between his breathing zone and bedroom air (λBZ).

The COVID-19 pandemic created a global crisis impacting not only healthcare systems, but also economics and society. Therefore, it is important to find novel methods for monitoring disease activity. Recent data have indicated that fecal shedding of SARS-CoV-2 is common, and that viral RNA can be detected in wastewater. This suggests that wastewater monitoring is a potentially efficient tool for both epidemiological surveillance, and early warning for SARS-CoV-2 circulation at the population level. In this study we sampled an urban wastewater infrastructure in the city of Ashkelon (~ 150,000 population), Israel, during the end of the first COVID-19 wave in May 2020 when the number of infections seemed to be waning. We were able to show varying presence of SARS-CoV-2 RNA in wastewater from several locations in the city during two sampling periods, before the resurgence was clinically apparent. This was expressed with a new index, Normalized Viral Load (NVL) which can be used in different area scales to define levels of virus activity such as red (high) or green (no), and to follow morbidity in the population at the tested area. The rise in viral load between the two sampling periods (one week apart) indicated an increase in morbidity that was evident two weeks to a month later in the population. Thus, this methodology may provide an early indication for SARS-CoV-2 infection outbreak in a population before an outbreak is clinically apparent.

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