Simulating allergenic tree pollen is important to protect sensitive population and to support bioaerosols monitoring effort. Using the regional air quality model GEM-MACH, a simulation was conducted adopting two new main hypotheses: 1) the use of vertical correlation concept to force the vertical dispersion (a method normally used in tracer data assimilation) and, 2) the use of a puff instead of a continuous pollen release. The simulation was compared with pollen observations in Montreal and with the corresponding statistical forecasts (issued daily by the Weather Network) at several locations in the province of Quebec and elsewhere. The comparison with the simulation was found satisfactory (outperform forecasts based on persistence or pollen calendar and is also superior to numerical simulation of tree pollen done elsewhere in North America). Simulation shows that, for the 2012 pollen season, the majority (88%) of the Betula pollen measured in Montreal originated from the Laurentides region. Another result of scientific importance obtained here is that Betula pollen episodes (observed or simulated birch pollen) in Montreal occur only when the average daily temperature is in the range of 10^o to 18^oC. This research is considered as a first step in forecasting bioaerosols in Canada within an air quality model.

模拟过敏性树花粉对于保护敏感人群和支持生物气溶胶监测工作非常重要。使用区域空气质量模型GEM-MACH，采用两个新的主要假设进行了模拟：1）使用垂直相关性概念强制垂直扩散（一种通常在示踪剂数据同化中使用的方法），以及2）使用吹而不是持续释放花粉。将模拟与蒙特利尔的花粉观测值以及魁北克省和其他地方的相应统计预测（由天气网络每天发布）进行了比较。与仿真的比较发现是令人满意的（基于持久性或花粉日历的优于预期的预测，也优于北美其他地区进行的树花粉的数值模拟）。在蒙特利尔测量的桦树花粉起源于Laurentides地区。在这里获得的科学重要性的另一个结果是，蒙特利尔的桦木花粉发作（观察到的或模拟的桦木花粉）仅在日平均温度在10 ^o到18 ^o C范围内时发生。该研究被认为是预报的第一步空气质量模型中的加拿大生物气溶胶。