In addition，smoking in the shopping center may cause fire and it is very dangerous for both your possessions and the customers.

In addition，smoking in the shopping center may cause fire，which is very dangerous for both your possessions and the customers.(非限制性定语从句)

参考范文

Dear Mr Smith，

　　I'm very glad to hear that your international shop­

　　ping center will build a "Non­smoking Supermarket"．In my opinion，it is a good idea to do so，for not only can it help the smokers to smoke less，but it can also do good to other customers' health while they are doing some shopping there.Since you have given up some benefits by not selling cigarettes，the smokers are most likely to support you in return.They will be happy to follow your suggestions，not considering their own rights and freedom again.In addition，smoking in the shopping center may cause fire，which is very dangerous for both your possessions and the customers.

　　All in all，the "Non­smoking Supermarket" will not affect your business.On the contrary，it will help you to attract more customers who want to keep healthy.

　　Best wishes!

Yours sincerely，

Li Hua