Experimental Study of the Effect of Relative Humidity on the Pulmonary Acinus Deposition of Inhalable Particulate Matter of the Hygroscopic Growth Type

2021 ◽  
Author(s):  
Rong Li ◽  
Liushuan Chang ◽  
Xin Jin
Keyword(s):  
Experimental Study ◽  
Particulate Matter ◽  
Relative Humidity ◽  
Hygroscopic Growth ◽  
Growth Type ◽  
Pulmonary Acinus ◽  
Inhalable Particulate Matter

scholarly journals Linking variations in sea spray aerosol particle hygroscopicity to composition during two microcosm experiments

2016 ◽  
Author(s):  
Sara D. Forestieri ◽  
Gavin C. Cornwell ◽  
Taylor M. Helgestad ◽  
Kathryn A. Moore ◽  
Christopher Lee ◽  
...  
Keyword(s):  
Light Scattering ◽  
Relative Humidity ◽  
Salt Content ◽  
Sea Salt ◽  
Sea Spray ◽  
Hygroscopic Growth ◽  
Phytoplankton Blooms ◽  
Aerosol Composition ◽  
Sea Spray Aerosol ◽  
Indoor And Outdoor

Abstract. The extent to which water uptake influences the light scattering ability of marine sea spray aerosol (SSA) particles depends critically on SSA chemical composition. The organic fraction of SSA can increase during phytoplankton blooms, decreasing the salt content and therefore the hygroscopicity of the particles. In this study, subsaturated hygroscopic growth factors at 85 % relative humidity (GF(85 %)) of SSA particles were quantified during two induced phytoplankton blooms in marine aerosol reference tanks (MARTs). One MART was illuminated with fluorescent lights and the other was illuminated with sunlight, referred to as the "indoor" and "outdoor" MARTs, respectively. GF(85 %) values for SSA particles were derived from measurements of light scattering and particle size distributions, concurrently with online single particle and bulk aerosol composition measurements. During both microcosm experiments, the observed bulk average GF(85 %) values were depressed substantially relative to pure, inorganic sea salt, by 10 to 19 %, with a one (indoor MART) and six (outdoor MART) day lag between GF(85 %) depression and the peak chlorophyll-a concentrations. The fraction of organiccontaining SSA particles generally increased after the peak of the phytoplankton blooms. The GF(85 %) values were inversely correlated with the fraction of particles containing organic or other biological markers. This indicates these particles were less hygroscopic than the particles identified as predominately sea salt containing and demonstrates a clear relationship between SSA particle composition and the sensitivity of light scattering to variations in relative humidity. The implications of these observations to the direct climate effects of SSA particles are discussed.

Experimental Study on Hygroscopicity of Rapeseed (Brassica Napus)

2012 ◽  
Vol 479-481 ◽  
pp. 2275-2278
Author(s):  
Ming Jin Yang ◽  
Wu Ming Xu ◽  
Tian Tang ◽  
Ling Yang ◽  
Feng Liu
Keyword(s):  
Experimental Study ◽  
Brassica Napus ◽  
Relative Humidity ◽  
Moisture Absorption ◽  
Early Period ◽  
Critical Relative Humidity ◽  
Temperature And Humidity ◽  
Higher Temperature

The hygroscopicity property of the rapeseed at different temperature and humidity was experimental studied in this paper. Tested results show that: the moisture absorption rates increase with the increase of relative humidity at the early period of absorption, and higher temperature leads to earlier reach of moisture equilibrium; the critical relative humidity(CRH) increases with the increase of temperature; the optional relative humidity for safety storage of rapeseed should be controlled less than 60%.

scholarly journals Hygroscopic properties of particulate matter and effects of their interactions with weather on visibility

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wan-Sik Won ◽  
Rosy Oh ◽  
Woojoo Lee ◽  
Sungkwan Ku ◽  
Pei-Chen Su ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Light Scattering ◽  
Low Cost ◽  
Weather Type ◽  
Hygroscopic Growth ◽  
Weather Factors ◽  
Mass Growth ◽  
Hygroscopic Properties ◽  
Weather Observations ◽  
Censored Regression Model

AbstractThe hygroscopic property of particulate matter (PM) influencing light scattering and absorption is vital for determining visibility and accurate sensing of PM using a low-cost sensor. In this study, we examined the hygroscopic properties of coarse PM (CPM) and fine PM (FPM; PM2.5) and the effects of their interactions with weather factors on visibility. A censored regression model was built to investigate the relationships between CPM and PM2.5 concentrations and weather observations. Based on the observed and modeled visibility, we computed the optical hygroscopic growth factor, $$f\left( {RH} \right)$$ f RH , and the hygroscopic mass growth, $$GM_{VIS}$$ G M VIS , which were applied to PM2.5 field measurement using a low-cost PM sensor in two different regions. The results revealed that the CPM and PM2.5 concentrations negatively affect visibility according to the weather type, with substantial modulation of the interaction between the relative humidity (RH) and PM2.5. The modeled $$f\left( {RH} \right)$$ f RH agreed well with the observed $$f\left( {RH} \right)$$ f RH in the RH range of the haze and mist. Finally, the RH-adjusted PM2.5 concentrations based on the visibility-derived hygroscopic mass growth showed the accuracy of the low-cost PM sensor improved. These findings demonstrate that in addition to visibility prediction, relationships between PMs and meteorological variables influence light scattering PM sensing.

scholarly journals Indoor Particulate Matter (PM2.5) and Comfort Parameters in a University Building

2020 ◽  
Vol 8 (2) ◽  
pp. 61-67
Author(s):  
Nurul Bahiyah Abd Wahid ◽  
Intan Idura Mohamad Isa ◽  
Ahmad Khairuddin Hassan ◽  
Muhammad Izzat Iman Razali ◽  
Ahmad Haziq Hasrizal ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Relative Humidity ◽  
Indoor Air ◽  
National Policy ◽  
Lecture Hall ◽  
Airborne Microorganisms ◽  
Code Of Practice ◽  
The Mean ◽  
Indoor Particulate Matter ◽  
Comfort Parameters

This study aims to determine the particulate matter (PM2.5) mass concentrations and the comfort parameters (total bacterial counts (TBC), total fungal counts (TFC), relative humidity and temperature) in a university building. The samplings were carried out in three different indoor areas, including lecture hall, laboratory and lecturer office. PM2.5 samples were collected over a period of 8 h sampling using a low volume sampler (LVS). The anemometer Model Kestrel 0855YEL was used to measure relative humidity and temperature parameters. The sampling of airborne microorganisms was conducted by using microbial sampler at 350 L air sampled volume. The results showed that the highest average of PM2.5 was at lecture hall (88.54 ± 26.21 µgm-3) followed by lecturer office (69.79 ± 19.06 µgm-3) and laboratory (47.92 ± 24.88 µgm-3). The mean of TBC and TFC readings recorded as follow; 32.71 ± 5.91 cfu m-3 and 76.71 ± 21.5 cfu m-3 for laboratory, 112.1 ± 29.06 cfu m-3 and 124.67 ± 23.35 cfu m-3 for lecturer office, 121.74 ± 19.33 cfu m-3 and 115.33 ± 8.08 cfu m-3 for lecture hall. The average of all comfort parameter was within the prescribed standard by Industry Code of Practice on Indoor Air Quality 2010 for all sampling sites. Therefore, all occupants of the building can work in a conducive and comfortable environment. This study is in line with the objectives of National Policy on the Environment (DASN), which focusing on achieving a clean, safe, healthy and productive environment for present and future generations.

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