**2.1 Sulphur mustard Inhalation**

Sulphur mustard (SM) is a chemical weapon used during the Iraq war against Iran of the late 1980s [93, 94]. It can produce damage in skin, eyes, and, , most importantly, in lung. 2- Chloroethyl ethyl sulphide (CEES) is a sulphur vesicating agent and an analogue of SM. Both of these agents are alkylating agents that affect cellular thiols and are highly toxic. CEES appears to decrease iNOS expression by associating with the LPS-induced stimulation of transcription factor NF-κB. CEES also alkylates the NF-κB consensus sequence, thus suppressing the binding of the NF-kB to the iNOS promoter. Even though the activation of NF-κB due to SM or CEES countering has been elucidated in different cell lines, the exact mechanism of this pathway is still poorly understood, and the question of whether activated NF-κB induces an inflammatory pathway remains to be elucidated [95].

#### **2.2 Diesel exhaust**

Diesel exhaust (DE) is a major pollutant;exposure increases a prominent inflammatory response in the airways, with induction of cytokines such as IL-8, IL-13 and activation of redox sensitive nuclear factors (NF-κB, AP-1) in the bronchial epithelium, including upregulation in the transcription of ICAM-1 and vascular endothelial adhesion molecules (VCAM-1). It has been established that DE activates the p38 and JNK MAPK pathways and causes the activation of NF-κB and AP-1 [96].
