Assessment of the impact of traffic volume on NO2 levels in Munich during the lock-down periods

<p>The global pandemic has many negative economic, social and health impacts, but the lock-downs also led to a reduction of traffic volume which resulted in lower NO<sub>2</sub> levels in some areas. Our study made use of different air quality measurement techniques (in-situ, on-road, satellite remote sensing) to monitor long-term NO<sub>2</sub> levels in Munich. While comparing NO<sub>2</sub> levels associate with traffic volume before and after a lock-down, other influences based on meteorological parameters should be considered as well. In addition to traffic data we used records of wind, mixing layer height, temperature, humidity and other meteorological parameters to analyze the impact on measured pollution levels using a Generalized Additive Model (GAM) regression. Our long-term study using data between 2018 and 2021 shows that the dominating factor is wind speed, followed by traffic volume as the main factors for impacting NO<sub>2</sub> levels, while absolute humidity and wind direction show less effects. We utilized those findings to find best suited time periods comparable to the lockdown time in terms of meteorological conditions. In order to focus on the traffic volume factor, we applied these findings to minimize other impact factors to evaluate the NO<sub>2</sub> variability of different years comparing to the data from the lockdown periods. A significant reduction of the ground level NO<sub>2</sub> concentrations in Munich during the early stage of the lockdown period in March 2020 could clearly be associated with a significant reduction of traffic volume.</p>

Moisture in New Zealand Bathrooms - Analysing Moisture Events

<p>A literature review was carried out on the impact of moisture in New Zealand homes as well as the role ventilation and occupant behaviour play in controlling this. Bathrooms in residential homes were identified as being especially vulnerable. NZS4303:1990, clause G4 Ventilation of the New Zealand Building Code, and clause E3 of the New Zealand Building Code were summarised to provide context for how New Zealand buildings are designed. Measurements taken in houses throughout New Zealand by BRANZ as part of the House Condition Survey were made available for analysis. This included measurements of relative humidity and temperature. Data from one Dunedin house was thoroughly explored. This involved three objectives. The first step focused on identifying periods of rapid change in the amount of moisture introduced to the indoor environment, measured in absolute humidity. These periods were named 'moisture events'. The second objective was to visually communicate the changes in temperature and absolute humidity taking place on individual days, highlighting moisture events. The third objective was to analyse the identified moisture events, finding the key areas to focus on for the full analysis as well as areas that could be explored in further research. This process was then applied to all remaining houses. Moisture events were grouped into four categories: increases, decreases, episodes, and combinations. Episodes were the focus of the analysis, representing moisture being actively introduced to the indoor environment and then removed. These categories were further filtered, identifying the moisture events were most likely to have had a large impact on the indoor environment. Days were broken into four hour periods, with the filtered moisture events taking place in each period recorded. These were used to identify patterns in moisture events for each house. If a certain pattern of moisture events frequently took place, then days containing that pattern were described as a 'typical day' for that house. The mean and median absolute humidity at the start, peak, and end of the unfiltered episodes from each house were then calculated. The mean and median episode length was also calculated. The results were compared to the Household Energy End-use Project (HEEP) and to the typical days for each house. The results were grouped according to factors such as the number of bathrooms in the house, the floor area, the house location, and the event length. The number of bathrooms present in the house was found to have a large impact on the size and frequency of moisture events. As expected, larger bathrooms recorded lower increases in absolute humidity from the start to the peak of episodes. Rooms with a greater volume would require more moisture to reach the same number of grams of water per cubic metre. However, the smallest bathrooms also recorded low increases in absolute humidity.</p>

Moisture in New Zealand Bathrooms - Analysing Moisture Events

<p>A literature review was carried out on the impact of moisture in New Zealand homes as well as the role ventilation and occupant behaviour play in controlling this. Bathrooms in residential homes were identified as being especially vulnerable. NZS4303:1990, clause G4 Ventilation of the New Zealand Building Code, and clause E3 of the New Zealand Building Code were summarised to provide context for how New Zealand buildings are designed. Measurements taken in houses throughout New Zealand by BRANZ as part of the House Condition Survey were made available for analysis. This included measurements of relative humidity and temperature. Data from one Dunedin house was thoroughly explored. This involved three objectives. The first step focused on identifying periods of rapid change in the amount of moisture introduced to the indoor environment, measured in absolute humidity. These periods were named 'moisture events'. The second objective was to visually communicate the changes in temperature and absolute humidity taking place on individual days, highlighting moisture events. The third objective was to analyse the identified moisture events, finding the key areas to focus on for the full analysis as well as areas that could be explored in further research. This process was then applied to all remaining houses. Moisture events were grouped into four categories: increases, decreases, episodes, and combinations. Episodes were the focus of the analysis, representing moisture being actively introduced to the indoor environment and then removed. These categories were further filtered, identifying the moisture events were most likely to have had a large impact on the indoor environment. Days were broken into four hour periods, with the filtered moisture events taking place in each period recorded. These were used to identify patterns in moisture events for each house. If a certain pattern of moisture events frequently took place, then days containing that pattern were described as a 'typical day' for that house. The mean and median absolute humidity at the start, peak, and end of the unfiltered episodes from each house were then calculated. The mean and median episode length was also calculated. The results were compared to the Household Energy End-use Project (HEEP) and to the typical days for each house. The results were grouped according to factors such as the number of bathrooms in the house, the floor area, the house location, and the event length. The number of bathrooms present in the house was found to have a large impact on the size and frequency of moisture events. As expected, larger bathrooms recorded lower increases in absolute humidity from the start to the peak of episodes. Rooms with a greater volume would require more moisture to reach the same number of grams of water per cubic metre. However, the smallest bathrooms also recorded low increases in absolute humidity.</p>

The Effects of Climate and Bioclimate on COVID-19 Cases in Poland

The correlations between air temperatures, relative and absolute humidity, wind, cloudiness, precipitation and number of influenza cases have been extensively studied in the past. Because, initially, COVID-19 cases were similar to influenza cases, researchers were prompted to look for similar relationships. The aim of the study is to identify the effects of changes in air temperature on the number of COVID-19 infections in Poland. The hypothesis under consideration concerns an increase in the number of COVID-19 cases as temperature decreases. The spatial heterogeneity of the relationship under study during the first year and a half of the COVID-19 pandemic in Polish counties is thus revealed.

KELEMBABAN UDARA DENGAN ALAT HUMYDIMETER PADA LAHAN SAWAH DI KELURAHAN TANAH MERAH

Humidity is the concentration of water vapor in the air. In agriculture, air humidity is associated with increased productivity and development of cultivated plants, humidity in the environment where it grows can determine the selection of appropriate plant species, the purpose of this study was to determine air humidity in paddy fields between April, May , and June, changes in air humidity at any time describe the water vapor content in the air can be expressed as absolute humidity, relative or vapor pressure deficit, relative humidity compares the actual water vapor content/pressure with its saturation state or the air's capacity to accommodate water vapor. The relationship between air humidity in paddy fields in Tanah Merah Village is relatively low, this is the impact of changes in temperature, quantity and quality of radiation, wind movement, air pressure, vegetation, and availability of water and productivity of irrigated ricefields

Outdoor PM2.5 concentration and rate of change in COVID-19 infection in provincial capital cities in China

This study investigates thoroughly whether acute exposure to outdoor PM2.5 concentration, P, modifies the rate of change in the daily number of COVID-19 infections (R) across 18 high infection provincial capitals in China, including Wuhan. A best-fit multiple linear regression model was constructed to model the relationship between P and R, from 1 January to 20 March 2020, after accounting for meteorology, net move-in mobility (NM), time trend (T), co-morbidity (CM), and the time-lag effects. Regression analysis shows that P (β = 0.4309, p < 0.001) is the most significant determinant of R. In addition, T (β = −0.3870, p < 0.001), absolute humidity (AH) (β = 0.2476, p = 0.002), P × AH (β = −0.2237, p < 0.001), and NM (β = 0.1383, p = 0.003) are more significant determinants of R, as compared to GDP per capita (β = 0.1115, p = 0.015) and CM (Asthma) (β = 0.1273, p = 0.005). A matching technique was adopted to demonstrate a possible causal relationship between P and R across 18 provincial capital cities. A 10 µg/m3 increase in P gives a 1.5% increase in R (p < 0.001). Interaction analysis also reveals that P × AH and R are negatively correlated (β = −0.2237, p < 0.001). Given that P exacerbates R, we recommend the installation of air purifiers and improved air ventilation to reduce the effect of P on R. Given the increasing observation that COVID-19 is airborne, measures that reduce P, plus mandatory masking that reduces the risks of COVID-19 associated with viral-particulate transmission, are strongly recommended. Our study is distinguished by the focus on the rate of change instead of the individual cases of COVID-19 when modelling the statistical relationship between R and P in China; causal instead of correlation analysis via the matching analysis, while taking into account the key confounders, and the individual plus the interaction effects of P and AH on R.

Gas conditioning during helmet noninvasive ventilation: effect on comfort, gas exchange, inspiratory effort, transpulmonary pressure and patient–ventilator interaction

Background There is growing interest towards the use of helmet noninvasive ventilation (NIV) for the management of acute hypoxemic respiratory failure. Gas conditioning through heat and moisture exchangers (HME) or heated humidifiers (HHs) is needed during facemask NIV to provide a minimum level of humidity in the inspired gas (15 mg H2O/L). The optimal gas conditioning strategy during helmet NIV remains to be established. Methods Twenty patients with acute hypoxemic respiratory failure (PaO2/FiO2 < 300 mmHg) underwent consecutive 1-h periods of helmet NIV (PEEP 12 cmH2O, pressure support 12 cmH2O) with four humidification settings, applied in a random order: double-tube circuit with HHs and temperature set at 34 °C (HH34) and 37 °C (HH37); Y-piece circuit with HME; double-tube circuit with no humidification (NoH). Temperature and humidity of inhaled gas were measured through a capacitive hygrometer. Arterial blood gases, discomfort and dyspnea through visual analog scales (VAS), esophageal pressure swings (ΔPES) and simplified pressure–time product (PTPES), dynamic transpulmonary driving pressure (ΔPL) and asynchrony index were measured in each step. Results Median [IqR] absolute humidity, temperature and VAS discomfort were significantly lower during NoH vs. HME, HH34 and HH37: absolute humidity (mgH2O/L) 16 [12–19] vs. 28 [23–31] vs. 28 [24–31] vs. 33 [29–38], p < 0.001; temperature (°C) 29 [28–30] vs. 30 [29–31] vs. 31 [29–32] vs 32. [31–33], p < 0.001; VAS discomfort 4 [2–6] vs. 6 [2–7] vs. 7 [4–8] vs. 8 [4–10], p = 0.03. VAS discomfort increased with higher absolute humidity (p < 0.01) and temperature (p = 0.007). Higher VAS discomfort was associated with increased VAS dyspnea (p = 0.001). Arterial blood gases, respiratory rate, ΔPES, PTPES and ΔPL were similar in all conditions. Overall asynchrony index was similar in all steps, but autotriggering rate was lower during NoH and HME (p = 0.03). Conclusions During 1-h sessions of helmet NIV in patients with hypoxemic respiratory failure, a double-tube circuit with no humidification allowed adequate conditioning of inspired gas, optimized comfort and improved patient–ventilator interaction. Use of HHs or HME in this setting resulted in increased discomfort due to excessive heat and humidity in the interface, which was associated with more intense dyspnea. Trail Registration Registered on clinicaltrials.gov (NCT02875379) on August 23rd, 2016.

Seasonal variation of dry and wet islands in Beijing considering urban artificial water dissipation

Urbanization has resulted in dry/wet island effects in built-up areas. Compared to the limited number of observational datasets, simulations can provide data with richer spatial distribution, thereby proving to be more helpful for revealing the spatial distribution of dry/wet islands. This study simulated dry/wet island effects during typical summer and winter conditions in Beijing by coupling the Artificial Water Dissipation Urban Canopy Model with the Weather Research and Forecasting model. Observations of relative humidity, absolute humidity, and temperature from weather stations in Beijing were used to verify the model. The results showed that in 2020, Beijing was prone to be a dry island during summer, with the relative humidity approximately 5–10% lower than the surrounding suburbs. The dry island effect was not obvious in winter, and Beijing tended to be a wet island. The influence of artificial water dissipation on dry/wet islands is higher in winter than in summer. By considering the water vapor from artificial water dissipation, humidity in urban areas can be simulated more accurately.

The role of absolute humidity in respiratory mortality in Guangzhou, a hot and wet city of South China

Background For the reason that many studies have been inconclusive on the effect of humidity on respiratory disease, we examined the association between absolute humidity and respiratory disease mortality and quantified the mortality burden due to non-optimal absolute humidity in Guangzhou, China. Methods Daily respiratory disease mortality including total 42,440 deaths from 1 February 2013 to 31 December 2018 and meteorological data of the same period in Guangzhou City were collected. The distributed lag non-linear model was used to determine the optimal absolute humidity of death and discuss their non-linear lagged effects. Attributable fraction and population attributable mortality were calculated based on the optimal absolute humidity, defined as the minimum mortality absolute humidity. Results The association between absolute humidity and total respiratory disease mortality showed an M-shaped non-linear curve. In total, 21.57% (95% CI 14.20 ~ 27.75%) of respiratory disease mortality (9154 deaths) was attributable to non-optimum absolute humidity. The attributable fractions due to high absolute humidity were 13.49% (95% CI 9.56 ~ 16.98%), while mortality burden of low absolute humidity were 8.08% (95% CI 0.89 ~ 13.93%), respectively. Extreme dry and moist absolute humidity accounted for total respiratory disease mortality fraction of 0.87% (95% CI − 0.09 ~ 1.58%) and 0.91% (95% CI 0.25 ~ 1.39%), respectively. There was no significant gender and age difference in the burden of attributable risk due to absolute humidity. Conclusions Our study showed that both high and low absolute humidity are responsible for considerable respiratory disease mortality burden, the component attributed to the high absolute humidity effect is greater. Our results may have important implications for the development of public health measures to reduce respiratory disease mortality.

The influence of vapor on the particle transport in high humid neighborhood environment

The particle transport characteristics have a significant effect on the exposure of residents and pedestrians to traffic pollutants in the street canyon. Around the lakeside environment, the diffusion of water vapor affects the flow characteristics of the gas mixture, which has a considerable influence on particle transport in the street canyon. A computational domain containing water bodies from which droplets were emitted by evaporation, a lakeside avenue and architectural groups were constructed. The RNG k-ε turbulence model and discrete phase model were applied to study the velocity, pressure, density of the airflow and particle transport characteristics in the street canyon with the absolute humidity increase (AHI) of 0, 3.8×10-4 g/kg, 1.7×10-3 g/kg, 3.1×10-3 g/kg. The saturated vapor pressure on the surface of droplets was modified by the pressure correction equation, which can limit the evaporation rate of the droplets. The simulation results demonstrated that, the diffusion of vapor could reduce the airflow velocity and increase the air pressure and density. The particle concentration in the street canyon increased with the AHI. Most of the pathogens in the air are transmitted with the flow of particle, and the study has some guiding significance to prevent the transmission of viruses.