The city of Homs has more than 300 days of west wind that carry the molecules that emit from the oil refinery to the center of the city.
Figure 1 shows the relation between wind speed and wind direction for a whole year [16].
Air Pollution Measurements:
The pollution values of Bottom Ashes, CO2, Pb, and CO in Area 1, Area 2 and the Oil refinery area were significantly higher than in Area 3 (representing the countryside of Homs, in our study, it represents the city of Hama). The average concentration of Bottom aches on the leaves of trees was higher in Area 1 and Area 2 compared to Area 3. The concentrations of CO in Area 1 and Area 2 were higher than in Area 3 [Table 1]. there were no measurements of the concentrations of H2S and SO2 gases in the city of Homs. Therefore, we relied on the measurements of these gases estimated by the Homs Refinery Company. The Homs Refinery Company estimated that the refining sites released over 2040 tons of H2S gas and over 588 tons of SO2 gas per month, which was carried by western winds towards the city of Homs [Fig 1]. Levels of carcinogenic volatile hydrocarbons (VOC) were not measured.
Table 1. The pollution levels of Bottom Ashes, CO2, Pb, and CO in Area 1, Area 2, and the Oil Refinery area exhibited significantly higher values compared to Area 3, which represents the countryside of Homs (in our study, it serves as a proxy for the city of Hama). The average concentration of Bottom Ashes on tree leaves was found to be higher in Area 1 and Area 2 when compared to Area 3. Furthermore, the concentrations of CO in Area 1 and Area 2 surpassed those in Area 3, as shown in Table 1. Unfortunately, measurements of H2S and SO2 gases were not available for the city of Homs. Hence, we relied on the estimated measurements of these gases provided by the Homs Refinery Company Those measurements were taken by the Atomic Energy Commission (Department of radiation protection and nuclear safety).
|
Oil Refinery
|
Area 1
|
Area 2
|
Area 3
|
Ashes
|
3000 (Fly aches) *
|
163 (Bottom ashes)
|
238 (Bottom ashes)
|
0 (Bottom ashes)
|
CO
|
-
|
0.45
|
2.25
|
0
|
CO2
|
-
|
380
|
540
|
363
|
O3
|
-
|
0.025
|
0.02
|
0.025
|
Pb
|
-
|
14
|
31
|
-
|
H2S
|
0.2
|
-
|
-
|
-
|
SO2
|
3.2
|
-
|
-
|
-
|
All of the above measurements are in ppm except for (*) which is in kg/h.
* This measurement was made on the chimney at a height of 300 meters.
Notes: 1- (Area 3) symbolizes the city of Hama.
2- Those measurements were taken by the Atomic Energy Commission (Department of radiation protection and nuclear safety) and The Company of Homs Oil Refinery [15].
3- (-) repsent for no available data.
|
Lung Cancer Incidence:
The number of lung cancer patients in the city of Homs was greater than the number of patients in the city of Hama during the period of 2015-2022. The incidence rate of lung cancer was higher in the city of Homs than in Hama, with one lung cancer patient per 3000 inhabitants in Homs compared to one patient per 6000 inhabitants in Hama, and the relative risk (RR) was 2.21, while the SIR in Homs was 2.2 with CI 95%(1.94-2.47) [Table 2].
The population of Homs and Hama cities during 2015-2022 (Table 2)
|
Homs
|
Hama
|
Total resident
|
800.000
|
922.000
|
Total new lung cancer cases
|
265
|
152
|
The incidence of lung cancer
|
1/3000
|
1/6000
|
Gender Differences:
The number of male lung cancer patients was higher than female lung cancer patients in both cities of Homs and Hama. During the study period of 2015-2022, in Homs, there were an average of 223 new male lung cancer patients, while in Hama, there were an average of 132 new male lung cancer patients. The crude incidence rate was 84.21 and 28.6 in 100,000 inhabitants, respectively [Table 3]. The average number of new female lung cancer patients during the study period in Homs was 42, while in Hama, there were an average of 20 new female lung cancer patients. The crude incidence rate was 10.5 and 4.3 in 100,000 inhabitants, respectively [Table 4].
The difference between Homs and Hama lung cancer crude incidence in male and female patients was statistically significant (P < 0.05).
Table 3. AVERAGE NUMBER OF NEW MALE LUNG CANCER CASES AND CANCER INCIDENCE RATES IN HOMS AND HAMA
China, Hong Kong
|
United States of America
|
Hama
|
Homs
|
Type of lung cancer
|
Lung Cancer incidence rates*
|
Lung Cancer incidence rates*
|
Lung Cancer incidence rates*
|
Number of new cancer cases
|
Lung Cancer incidence rates*
|
Number of new cancer cases
|
|
9.9
|
8.9
|
19.9
|
61
|
38.9
|
103
|
SCC
|
19.1
|
7.9
|
10.5
|
32
|
23
|
61
|
AC
|
4.5
|
4.8
|
11.1
|
34
|
18.9
|
50
|
SCLC
|
1.5
|
1.9
|
1.6
|
5
|
3.4
|
9
|
LCC
|
35
|
23.5
|
43.25
|
132
|
84.2
|
223
|
Total
|
Per 100.000 population*
SCC, squamous cell carcinoma; AC, adenocarcinoma; LCC, large cell carcinoma; SCLC, small cell lung cancer.
Notes: 1- Homs includes data from the 3 available cancer registries in Homs.
2- Hama includes data from the 1 available cancer registries in Hama.
|
|
Table 4. AVERAGE NUMBER OF NEW FEMALE LUNG CANCER CASES AND CANCER INCIDENCE RATES IN HOMS AND HAMA
China, Hong Kong
|
United States of America
|
Hama
|
Homs
|
Type of lung cancer
|
Lung Cancer incidence rates*
|
Lung Cancer incidence rates*
|
Lung Cancer incidence rates*
|
Number of new cancer cases
|
Lung Cancer incidence rates*
|
Number of new cancer cases
|
1.3
|
4.9
|
1.3
|
4
|
8
|
21
|
SCC
|
12.6
|
7.6
|
3.3
|
10
|
3.8
|
10
|
AC
|
0.6
|
4.6
|
0.6
|
2
|
2.7
|
7
|
SCLC
|
0.5
|
1.2
|
1.3
|
4
|
1.5
|
4
|
LCC
|
15
|
18.3
|
6.6
|
20
|
16.1
|
42
|
Total
|
per 100.000 population*
SCC, squamous cell carcinoma; AC, adenocarcinoma; LCC, large cell carcinoma; SCLC, small cell lung cancer.
Notes: 1- Homs includes data from the 3 available cancer registries in Homs.
2- Hama includes data from the 1 available cancer registries in Hama.
|
Cancer Types:
The highest percentage of male and female patients' cancer type in the city of Homs was Squamous cell carcinoma, while in the city of Hama, the highest percentage of male patients was also Squamous cell carcinoma, and in females, the higher percentage was for Adenocarcinoma. There was no significant difference in types of lung cancer between Homs and Hama [Fig 3].
Age of diagnosis:
The mean age for diagnosing lung cancer in the city of Homs was 61, while it was 59 in the city of Hama. There was no significant difference in the age of diagnosis of lung cancer between Homs and Hama.
Tumor Location:
Tumors in male patients in the city of Homs were more localized in the right lung, while in females, the percentage was almost equal in both lungs. In the city of Hama, there was a slight increase in the number of male patients infected with the right lung, while there was no significant difference in the location of the tumor between the lungs of female patients.