Narrative:

Divert to ZZZ. Fumes and very slight haze around captains side window; a smell of engine coking (burning oil or electronics smell). 15-20 minutes after departure I turned to my first officer and asked if he smelled anything. He did not. We continued; the smell persisted and about 1.5 hrs into the flight I began to become very bothered by the smell. I felt like I needed fresh air and decided to begin breathing out of my O2 mask. I began to feel physical issues; like shortness of breath and a little dizzy and thinking about needing to throw up. After a few minutes I got out of my seat for a restroom break and to determine if the smell was in the cabin. It was not. While I was in the restroom the a flight attendant came up and sat in my seat. She complained of the smell to the first officer. He went to check it out and realized it was on my side but not his. I came back from the restroom and at this point it became clear to us that there was definitely a smell on just my side. We ran the QRH and then talked to dispatch and maintenance. We used the masks and [advised ATC]; then headed for ZZZ.

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Original NASA ASRS Text

Title: A320 Captain reported a fume event in cruise that resulted in a diversion.

Narrative: Divert to ZZZ. Fumes and very slight haze around Captains side window; a smell of engine coking (burning oil or electronics smell). 15-20 minutes after departure I turned to my First Officer and asked if he smelled anything. He did not. We continued; the smell persisted and about 1.5 hrs into the flight I began to become very bothered by the smell. I felt like I needed fresh air and decided to begin breathing out of my O2 mask. I began to feel physical issues; like shortness of breath and a little dizzy and thinking about needing to throw up. After a few minutes I got out of my seat for a restroom break and to determine if the smell was in the cabin. It was not. While I was in the restroom the A Flight Attendant came up and sat in my seat. She complained of the smell to the First Officer. He went to check it out and realized it was on my side but not his. I came back from the restroom and at this point it became clear to us that there was definitely a smell on just my side. We ran the QRH and then talked to Dispatch and Maintenance. We used the masks and [advised ATC]; then headed for ZZZ.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.