1. Dust storms and ocular health
Dr. Ramezani
Ophthalmologist
Kermanshah Uni. Of Med. Sci.

2. Introduction
as a meteorological phenomenon, dust event usually occurs in arid and semi-arid areas after strong winds, and carries large amounts of dust and sand from sparsely vegetated dry deserts. Areas known as dust prone locations are those with the annual average rainfall of ≤100 mm.

3. Dust events in the atmosphere have direct and indirect impacts on climate change.
The direct effects include the absorption and scattering of sunlight and this condition affects the Earth's radiation budget.
Indirectly it can affect clouds’ lifetime by changing their properties. Reduction in visibility due to atmospheric dust is another main problem that causes an increased challenge in aviation industry. A large amount of particles are suspended in the air can also affect human health.
Each 10 microgram per meter cubed (μg/m3) increase in the mass concentration of PM10 causes a 5% increase in the total number of premature deaths .

5. Dust source identification was carried out by applying the presented methodology on 70 dust storms, which occurred in the Middle East in the period between 2001 and Results indicate that 367 different source points have participated in dust storm generation in the region.

9. According to WHO, Sanandaj was ranked the third polluted city in the world in term of PM10

10. The average PM10 concentration was 160. 63 μg/m³
The average PM10 concentration was μg/m³. The lowest and highest concentrations of PM10 were in May and June respectively. The average PM10 concentration during the non-dusty days was (μg /m³). The Iranian national PM10 standard is the same as WHO guideline, which is 50 μg/m3 for daily average. The findings revealed that the daily mean PM10 concentrations exceeded the WHO guidelines in 77% of the days sampled.

12. They were distributed survey sheets for nasopharyngeal (sneezing, nasal discharge, congestion, itching, sore throat, and scratchy throat), ocular (itching, lacrimation, hyperemia, and bleary eyes), respiratory (cough, sputum, breathlessness, chest pain, chest discomfort, and dyspnea), and skin (itching, eczema, pain, and reddish skin) symptoms from the 1st to the 25th of February 2009.

13. The overall symptom score for Asian dust days (0. 23 ± 0
The overall symptom score for Asian dust days (0.23 ± 0.03) was significantly higher than for non–Asian dust days(0.19±0.04, p=.020; Figure 3). The overall symptom score for Asian dust days was higher than for non–Asian dust days

15. Particulate of Asian dust is principally composed of rock-forming minerals such as quartz and feldspar, and clay minerals such as mica, kaolinite, and chlorite. Analysis of Asian dust particles has shown the presence of ammonium ions, sulfate ions, nitrate ions, and metallic compound that are not considered to originate from the soil. The possibility has been suggested that Asian dust particles adsorb anthropogenic atmospheric pollutants during transport.

17. The area was wiped around the eyes of patients who were diagnosed with acute conjunctivitis to remove deposits, and eyes were washed using physiological solution.

18. Si/Al compounds were detected in eyes of all conjunctivitis patients except for patient 37, with a total content of approximately 25%. Other metallic compounds comprised 55.6% of total particles. higher scores were observed in the subgroup with Si/Al levels greater than mean of 25.8%. However, other metallic and total compounds did not exhibit marked differences using this quantitative methodology. however, our data do not necessarily indicate that ADP was a causative factor in the observed conjunctivitis,

21. Studies suggested that dust particles composed of quartz, anamorphous and crystalline silica. “Si-rich” particles (which display maximal weight ratio of Si. in analyzed elements) comprised 72–80% of all particles. “Si-rich” particles were those containing Si and Al. In addition, the particles include chemicals derived from air pollutants such as sulfate (SO4 ) and nitrate (NO3 ) and microbial agents such as bacteria, fungi, fungal spores, and viruses, which survive long-distance transportation.

22. The dense innervation of the ocular surface is extremely sensitive to environmental agents. Further, eyes are protected by only a thin layer of tear film from potentially damaging exterior influences. Thus, the human eye is susceptible to the effects of air pollutants. The air pollutants nitrogen dioxide (NO2), sulfur dioxide (SO2), ozone (O3), particulate matter (PM10), and ADS increase the risk of number of outpatient visits associated with conjunctivitis.

23. Discussion….