Protection from exhaust fumes

Hey! I hope this is relevant to the community. I’ve recently started a job as the groundskeeper at a hotel. The grounds have lots of very mature deciduous trees – and the amount of leaves are crazy at this time of year. I use a Stihl BR 450 backpack leaf blower for around 2 hours every day I work and tbh I’m starting to worry about all the exhaust fumes I’m inhaling. If anybody has advice on equipment or steps I can take to protect myself, I would be very grateful. I bought the following mask to filter out the fumes but I can still smell them do assume it isn’t working. https://www.screwfix.com/p/3m-4251-one-size-half-mask-respirator-a1-p2/464HY?gclsrc=aw.ds&gad_source=1&gbraid=0AAAAAD8IdPwPzYjq2Dx92uJ1u93g4bBp2&gclid=EAIaIQobChMIw82kkfKmiQMVRo9QBh38RB0XEAQYAiABEgJZ5PD_BwE&gclsrc=aw.ds#product_additional_details_container

Many thanks!