Capturing Spatial and Temporal Patterns of NO2 in Cities using mobile and stationary DOAS measurements

<p>The problem of elevated NO<sub>2</sub> levels in cities has gained some attention in the public in recent years and has given rise to questions about the plausibility of banning diesel engines in cities, the meaning of exceedances of air quality limits and the effects of corona lock-downs on air quality to name a few. Urban air quality is typically monitored using a relatively small number of monitoring stations. Those in-situ measurements follow certain guidelines in terms of inlet height and location relative to streets, but the question remains how a limited number of point measurements can capture the spatial variability in cities. In this talk we present two measurement campaigns in Hong Kong and Munich where we utilized a combination of mobile in-situ and stationary remote sensing differential optical absorption spectroscopy (DOAS) instruments. We developed an algorithm to separate spatial and temporal patterns in order to generate pollution maps that represent average NO<sub>2</sub> exposure. </p> <p>We use those maps to identify pollution hot spots and capture the weekly cycles of on-road NO2 levels and spatial dependency of long-term changes and we analyze how on-road measurements compare to monitoring station data and how the measurement height and distance to traffic emissions have to be considered when interpreting observed concentration patterns.</p>

Temporal variations in COVID-19: an epidemiological discussion with a practical application

Objective We aimed to characterize the temporal variation in coronavirus disease 2019 (COVID-19) infection and mortality as a possible tool to monitor and control the spread of this disease. Methods We analyzed cyclicity and synchronicity in cases of COVID-19 infection and time series of deaths using Fourier transform, its inverse method, and statistical treatments. Epidemiological indices (e.g., case fatality rate) were used to quantify the observations in the time series. The possible causes of short-term variations are reviewed. Results We observed that were both short-term and long-term variations in the COVID-19 time series. The short cycles were 7 days and synchronized among all countries. This periodicity is believed to be caused by weekly cycles in community social factors, combined with diagnostic and reporting cycles. This could also be related to virus–host–community dynamics. Conclusion The observed synchronized weekly cycles could serve as herd defense by providing a form of social distancing in time. The effect of such temporal distancing could be enhanced if combined with spatial distancing. Integrated spatiotemporal distancing is therefore recommended to optimize infection control strategies, taking into account the quiescent and active intervals of COVID-19.

Vanishing weekly cycles in American and Canadian hydropeaking rivers

<p>Sub-daily and weekly streamflow cycles termed hydropeaking are common features in regulated rivers across the globe. Weekly periodicity in flows arises from fluctuating hydropower demand and production tied to socioeconomic activity, typically with higher consumption during weekdays followed by reductions on weekends. In this presentation, we will introduce a novel weekly hydropeaking index to quantify the intensity and prevalence of weekly hydropeaking cycles at 368 sites across the United States of America (USA) and Canada over 1920-2019. Our results reveal a robust weekly hydropeaking signal exists at 1.3% of available sites starting in 1920 with a fraction that peaks at 16.7% of sites in 1963. Highly hydropeaking signals then diminish to only 3.3% of available sites in 2019, marking a 21st century declining pattern in hydropeaking intensity across parts of North America. Application of the Mann-Kendall Test reveals 95 locally significant declines in weekly hydropeaking intensity between 1980-2019. Our results can be attributed to diminishing differences between streamflow on weekends versus weekdays in regulated rivers across Canada and the USA. We will conclude the presentation with a discussion on how these findings may be tied to shifts in socioeconomic activity, alternative modes of electricity production, and legislative and policy changes impacting water management in regulated systems.</p>

Study regarding the effects of sprints on the injury rate of football players

The football game in Romania begins to be played according to certain scientifically proven benchmarks, which is evidenced by the results and studies published every year. The latest international studies show that photocell-controlled sprinting over a 50-meter distance at an intensity of more than 95% of the player’s maximum potential decreases the risk of injury during a match. This is due to the fact that there are weekly competitive microcycles in which, through the chosen exercises or just by the nature of the position played, many athletes do not experience this scenario during training but they are fully faced with it during a match. Thus, our purpose was to conduct a comparative study in order to observe the effects of sprints on the injury rate of football players during matches across weekly cycles. Participants in this study were 20 professional football players who, according to the established protocol, followed a preventive injury programme including sprints performed at an intensity of over 95%. These exercises must be practised throughout the training period, our study intending to demonstrate that the game activity is the reference point when building training sessions, and each game scenario should be simulated or practised in the training process.

The heartbeat of the city

Human activity is organised around daily and weekly cycles, which should, in turn, dominate all types of social interactions, such as transactions, communications, gatherings and so on. Yet, despite their strategic importance for policing and security, cyclical weekly patterns in crime and road incidents have been unexplored at the city and neighbourhood level. Here we construct a novel method to capture the weekly trace, or “heartbeat” of events and use geotagged data capturing the time and location of more than 200,000 violent crimes and nearly one million crashes in Mexico City. On aggregate, our findings show that the heartbeats of crime and crashes follow a similar pattern. We observe valleys during the night and peaks in the evening, where the intensity during a peak is 7.5 times the intensity of valleys in terms of crime and 12.3 times in terms of road accidents. Although distinct types of events, crimes and crashes reach their respective intensity peak on Friday night and valley on Tuesday morning, the result of a hyper-synchronised society. Next, heartbeats are computed for city neighbourhood ‘tiles’, a division of space within the city based on the distance to Metro and other public transport stations. We find that heartbeats are spatially heterogeneous with some diffusion, so that nearby tiles have similar heartbeats. Tiles are then clustered based on the shape of their heartbeat, e.g., tiles within groups suffer peaks and valleys of crime or crashes at similar times during the week. The clusters found are similar to those based on economic activities. This enables us to anticipate temporal traces of crime and crashes based on local amenities.

Diurnal and weekly patterns of primary pollutants in Beijing under COVID-19 restrictions

Restrictions on movement in Beijing to limit the COVID-19 epidemic tended to change the daily and weekly cycles of emissions of primary pollutants.