The third factor had high loadings of V, Ni and S, and this clearly represented oil combustion similarly to PM2.5 Factor 2. The average mass contribution of this heavy oil combustion source was 14 μg m–3 (or 18% mass). Sites 5 and 6 in immediate proximity and downwind of Jeddah refinery and sea port had the largest contribution of 19 and 31 μg m–3 (or 26 and 29% PM10 mass). Site 1, which is also close to the seashore, was likely affected by ships’ exhaust. Temporal variation of oil source contributions to Site 4 confirms that this is like a point source, and thus highly affected by wind direction. For example, during concurrent sampling at Sites 4 and 7, the overall contribution of oil combustion source to Site 4 was twice as high (24 μg m–3), quite possibly because Site 7 (with 11 μg m–3) was not downwind of the refinery and port emissions. Notably, the northwest contribution is missing in Site 4 PM10 pollution rose, compared to PM2.5. The fourth factor was loaded with Na and Cl, which we attributed to coarse sea salt of marine aerosol which contributed on average 6.7 μg m–3 of PM10 mass (or about 9% mass). This source was reasonably expressed under favorable winds from the sea. Site 1 had larger overall contribution from the marine aerosol due to its proximity to the seashore
The third factor had high loadings of V, Ni and S, and this clearly represented oil combustion similarly to PM2.5 Factor 2. The average mass contribution of this heavy oil combustion source was 14 μg m–3 (or 18% mass). Sites 5 and 6 in immediate proximity and downwind of Jeddah refinery and sea port had the largest contribution of 19 and 31 μg m–3 (or 26 and 29% PM10 mass). Site 1, which is also close to the seashore, was likely affected by ships’ exhaust. Temporal variation of oil source contributions to Site 4 confirms that this is like a point source, and thus highly affected by wind direction. For example, during concurrent sampling at Sites 4 and 7, the overall contribution of oil combustion source to Site 4 was twice as high (24 μg m–3), quite possibly because Site 7 (with 11 μg m–3) was not downwind of the refinery and port emissions. Notably, the northwest contribution is missing in Site 4 PM10 pollution rose, compared to PM2.5. The fourth factor was loaded with Na and Cl, which we attributed to coarse sea salt of marine aerosol which contributed on average 6.7 μg m–3 of PM10 mass (or about 9% mass). This source was reasonably expressed under favorable winds from the sea. Site 1 had larger overall contribution from the marine aerosol due to its proximity to the seashore
การแปล กรุณารอสักครู่..