While several genetic factors have been identified to either cause or influence ALS [71], approximately80–90% of cases are sporadic, suggesting an impact of environmental factors [69]. A single case-control study found anincreased risk of ALS diagnosis with residential exposure toambient solvent exposure [46]. At present, reports on anyassociation of ALS with outdoor ambient air pollution arecurrently unavailable, emphasizing the importance of futureresearch in this area