essay 代寫：PM2.5在大氣中傳播的因素
PM2.5是指直徑小於或等於2.5微米的顆粒物。這些是最主要的污染物之一，即使是最小的空間也有可能導致呼吸和心血管疾病。這些污染物的產生是由於一些人爲活動，如作物燃燒、車輛排放等。它們的傳播取決於大氣條件，如風向和風速、溫度、降水等。
essay 代寫：PM2.5在大氣中傳播的因素
這份報告試圖瞭解是什麼因素影響了PM2.5的傳播，以及大氣條件是什麼阻礙了它的傳播。如上所述，PM2.5主要是由人類活動產生的，但其在大氣中的滯留和跨地域傳播受大氣條件的控制(Liang et al.， 2015)。例如，如果污染物在北京西南100公里處排放，而風向是東北方向，那麼這些排放很可能會影響北京的PM2.5濃度。此外，如果降水發生，其源頭的濃度會下降，儘管風向朝東北方向移動，但對北京的影響將是最小的。因此，瞭解導致顆粒物在大氣中傳播的因素是很重要的。
essay 代寫：PM2.5在大氣中傳播的因素
PM2.5 refers to particulate matters which have a diameter of 2.5 micrometres or less. These are one of the major pollutants that can pass even the smallest spaces and have the potential to cause respiratory and cardiovascular diseases. These pollutants are generated due to several anthropogenic activities like crop burning, emissions from vehicles, etc. Their spread however is determined by atmospheric conditions like wind direction and speed, temperature, precipitation, etc.
essay 代寫：PM2.5在大氣中傳播的因素
This report tries to understand what factors influence the spread of PM2.5 and what atmospheric conditions deter its spread. As stated above, PM2.5 is largely generated by human activities but its retention in the atmosphere and spread across geographies is governed by atmospheric conditions (Liang et al., 2015). For instance, if pollutants are emitted at 100km south-west of Beijing but the wind is blowing in north-east direction, it is likely that these emissions would affect the PM2.5 concentration of Beijing. Besides, if precipitation occurs, the concentration at source itself would fall and despite the wind moving towards north-east, the effect at Beijing would be minimal. Therefore, it is important to understand the factors which catalyse the spread of particulates in the atmosphere.
