Dust storm and atmosphere air pollution in uzbekistan

What is PM, and how does it get into the air? 
PM stands for particulate matter (also called particle pollution): the term for a 
mixture of solid particles and liquid droplets found in the air. Some particles, such 
as dust, dirt, soot, or smoke, are large or dark enough to be seen with the naked 
eye. Others are so small they can only be detected using an electron microscope.
Particle pollution includes: 
PM
10 
: inhalable particles, with diameters that are generally 10 micrometers 
and smaller; and 
PM
2.5
: fine inhalable particles, with diameters that are generally 2.5 
micrometers and smaller. 
How small is 2.5 micrometers? Think about a single hair from your head. The 
average human hair is about 70 micrometers in diameter – making it 30 times 
larger 
than 
the 
largest 
fine 
particle 
(Figure 
1.) 
https://www.airnow.gov/international/us-embassies-and-consulates/.
Figure 1. Human hair and dust particles 
The World Health Organization (WHO) Permissible Dust Concentration is 
defined as follows (average 24-hour / average annual https://www.breeze-
technologies.de/blog/new-2021-who-air-quality-guideline-limits/ ): 
PM for 10 particles - 45µg / m3 -15 µg / m3; 
PM for 2.5 particles - 15µg / m3 -5 µg / m3. 
The chemical composition of the dust is also of great hygienic importance, as 
the dust can have a fibrogenic, irritating or itchy, toxic (toxic), allergenic effect on 

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Central Asian Journal of Medicine
uzjournals.edu.uz/tma 
39 
2022#2
the body. The damage of dust depends primarily on its dispersion, the size of the 
dust particles and their concentration in the respiratory tract (Figure 2) 
https://ane4bf-datap1.s3.eu-west-1.amazonaws.com/wmod8_gcos/s3fs-
public/gcos-status_report_full_text-
240_lr_compressed.pdf?FDdn12yqICpIxugb2V7hTQ9lTIcMRQFd.