Air Mass Parameters Research Articles

Influence of air pollution on the development of intensive care unit pneumonia patients: a summary of 2 454 cases from 2014 to 2016 in Nanchang City

To analyze the main characteristics of air pollution in Nanchang City, and discuss the correlation between air pollution exposure (especially PM2.5) and the development of pneumonia related intensive care unit (ICU) patients and their lag effect. 2 454 patients who lived in Nanchang City admitted to ICU of Jiangxi Provincial People's Hospital from January 1st, 2014 to December 31st, 2016 were enrolled. According to the diagnosis, the patients were divided into pneumonia group (156 cases) and non-pneumonia group (2 298 cases). The general clinical characteristics of patients and air pollution concentration in Nanchang in the year between 2014-2016 were collected. Multiple regression model was used to analyze the influence of meteorological factors on the condition of ICU patients associated with pneumonia. Using odds ratio (OR), the correlation intensity of air pollution exposure and pneumonia related ICU patients' development was reflected, and the confidence level of association intensity was reflected by the 95% confidence interval (95%CI). The distribution lag nonlinear model (DLNM) was established to evaluate the effect of air mass parameters on the time lag effect. The results of air pollution analysis in Nanchang City in the year between 2014-2016 showed that the annual average concentration of carbon monoxide (CO), sulfur dioxide (SO2) and nitrogen dioxide (NO2) was low and maintained at the same level in the year between 2014-2016. The annual average concentration of CO and NO2 increased in the year between 2014-2016, but the average annual concentration of SO2 decreased rapidly in the year between 2014-2016, and the average annual concentration of PM2.5 tended to slow down after the year between 2014-2016. The annual average concentration of PM10 decreased in the year between 2014-2016, but continued to rise in the year between 2014-2016. The annual mean concentration of O3 showed a trend of continuous increase from the year between 2014-2016. The age of pneumonia group was generally higher than that of non-pneumonia group, most of them were male, and had higher expected mortality and acute physiology and chronic health evaluation II (APACHE II) score. The average air temperature in the pneumonia group was lower than that in the non-pneumonia group on the day of entering the group, and the air pollutants such as PM2.5 and PM10 were significantly higher than those in the non-pneumonia group. The analysis of multiple regression models showed that PM2.5 and air temperature were significantly related to patients with ICU pneumonia on the day of entry (PM2.5: OR = 1.02, 95%CI = 1.00-1.03, P < 0.05; air temperature: OR = 0.96, 95%CI = 0.92-0.98, P < 0.05), and the effect of PM2.5 on patients with ICU pneumonia could last for at least 5 days (OR = 1.04, 95%CI = 1.00-1.09, P < 0.05), and the effect disappeared until the 7th day. According to the analysis of the influence of different concentrations of PM2.5 on ICU pneumonia patients, when the PM2.5 concentration reached 200 μg/m3, its effect on ICU pneumonia patients would last for 5 days (OR = 1.45, 95%CI = 1.07-1.76, P < 0.01). PM2.5 and air temperature are significantly related to the condition of ICU patients with pneumonia, and the influence of high concentration of PM2.5 on ICU patients with pneumonia has a lag effect.

Wavelet analysis of low altitude infrared transmission in the coastal environment

Analysis of medium and long wavelength infrared light transmission measurements collected during an intensive experimental investigation over San Diego Bay, CA, USA, has been performed using Morlet wavelets. Wavelet analysis shows locally periodic trends in signals and shows how these trends evolve in time. The analysis has shown the effect of the relative humidity and the windspeed on the transmission in both mid- and long-wave bands of the IR. The effect of air mass parameter does not appear to be strongly correlated. The wavelet representations of the data given in the figures provide a useful overview of the effects of the atmosphere on infrared transmission.

Air mass parameterization and coastal aerosol modeling

The United States Navy is increasingly concerned with operations in coastal environments. One key threat to ships is the easily launched high precision anti-ship weaponry readily available in the world-arms market. Fleet units operating in either the open ocean or in coastal regions must be able to determine the standoff ranges at which they can detect and/or track such sophisticated weaponry. The Navy is presently developing and utilizing infrared (IR) technology for the detection and identification of such threats. Atmospheric aerosol extinction, refraction, turbulence and infrared sea and terrain background models in LOWTRAN and MODTRAN are presently inadequate for representing IR propagation close to the ocean surface and in coastal environments. This requires accurate models to describe the effects of low level ocean and coastal aerosols to be incorporated into LOWTRAN and MODTRAN for determining the performance of EO systems used for detecting these low-altitude targets.Not much is known concerning the coastal air mass characteristics required for advanced aerosol modeling. Since the diverse air mass transitions that frequent coastal environments may have profound effects upon aerosol properties and EO propagation, a good assessment of the NAM/NOVAM air mass parameter for coastal applications is essential. The NAM/NOVAM dN/dr aerosol size distribution model consists of three log normal distributions, the first component being scaled proportionate to the square of the air mass parameter (AMP). Therefore, when using NAM/NOVAM for calculating extinction coefficients and optical depths in the MBL, the AMP is the most critical input parameter and is, of course, the most difficult to obtain. Several techniques are being evaluated or utilized to obtain this parameter including air mass trajectory analysis, radon, condensation nuclei, and multiple wavelength nephelometer measurements. All of these techniques are in-situ measurements for a given geographic location. When considering the complexity and variability of the air mass characteristics within a coastal environment, an alternate remote sensing technique for determining the AMP must be determined for NAM/NOVAM to be applicable for coastal application. The purpose of this paper is to present an alternative approach for determining the surface AMP from satellite upwelling radiance measurements, LOWTRAN, and the NOVAM aerosol model.Using satellite detected upwelling radiance measurements, multiple wavelength satellites, such as the NOAA -14 AVHRR, can be used to determine the total atmospheric aerosol optical depth (ODSat) and its geographical variability. Utilizing this satellite OD data base and the LOWTRAN calculated OD (ODLOWTRAN) for tropospheric aerosol scatter above the marine boundary layer (MBL), the contribution to the total aerosol ODSat by the boundary layer (ODMBL) for a geographic location can be determined by subtracting these two values, e.g., ODMBL = ODSat - ODLOWTRAN. The AMP associated with this OD (ODMBL) can then be related to the NAM/NOVAM aerosol model by exercising NAM/NOVAM as a function of AMP until the NAM/NOVAM calculated OD (ODNOVAM) agrees with that required from the satellite observation for the MBL. The resulting AMP represents that required as an input to NAM/NOVAM for predicting the IR propagation characteristics within the MBL as a function of wavelength for a specific geographic location and time.

The Development of Quantitative Relationships between Orographic Precipitation and Air-Mass Parameters for Use in Forecasting and Cloud Seeding Evaluation

Abstract The physical basis for a relationship between orographic precipitation and air-mass characteristics, wind flow pattern and gross terrain features is outlined. Consideration is also given to the manner in which the precipitation falls from cloud and is caught in a rain gage. A model is developed which is employed in conjunction with numerous storm sounding data to establish semi-empirical relationships between precipitation at four mountain stations in Southern California and upwind air-mass characteristics. The sounding sites were several hours upwind of the mountain stations. This arrangement makes it possible to employ the relationships established for short term quantitative precipitation forecast purposes as well as for cloud seeding evaluation. It is believed that the general method employed is applicable in other climatic zones.