He works in a mixed environment and is worried about his fast
Question

                I work in a company where there is no other man but me. Does my mixing with women have any effect on my fast?.
Praise be to Allah.Mixing 
    between men and women in the workplace has obvious bad effects on both men 
    and women. These include the following: 
1 – Haraam 
    looks. Allaah has commanded the believers, men and women, to lower their 
    gaze. Allaah, may He be exalted, says (interpretation of the meaning): 
“Tell the 
    believing men to lower their gaze (from looking at forbidden things), and 
    protect their private parts (from illegal sexual acts). That is purer for 
    them. Verily, Allaah is All‑Aware of what they do.
31. And 
    tell the believing women to lower their gaze (from looking at forbidden 
    things), and protect their private parts (from illegal sexual acts) and not 
    to show off their adornment except only that which is apparent”
    [al-Noor 24:30, 31]
In Saheeh 
    Muslim (2159) it is narrated that Jareer ibn ‘Abd-Allaah (may Allaah be 
    pleased with him) said: I asked the Messenger of Allaah  (peace and 
    blessings of Allaah be upon him) about an accidental glance and he told me 
    to avert my gaze. 
2 – There 
    may be haraam touching, which includes shaking hands. The Prophet  
    (peace and blessings of Allaah be upon him) said: “For one of you to be 
    struck in the head with an iron needle would be better for him than touching 
    a woman who is not permissible for him.” Narrated by al-Tabaraani from the 
    hadeeth of Ma’qil ibn Yasaar; classed as saheeh by al-Albaani in Saheeh 
    al-Jaami’, no. 5045. 
3 – Mixing 
    may lead to a man being alone with a woman who is not his mahram, which is 
    haraam, because the Prophet  (peace and blessings of Allaah be upon him) 
    said: “No man is alone with a woman but the Shaytaan is the third one 
    present.” Narrated by al-Tirmidhi, 2165; classed as saheeh by al-Albaani in
    Saheeh al-Tirmidhi. 
According to 
    another report: “Whoever believes in Allaah and the Last Day, let him not be 
    alone with a woman who does not have a mahram with her, for the third one 
    present will be the Shaytaan.” Narrated by Ahmad and classed as saheeh by 
    al-Haakim, and al-Dhahabi agreed with him. Also classed as saheeh by 
    al-Albaani in Ghaayat al-Maraam, 180. 
4 – Another 
    of its evil results is that a man may become attracted to and infatuated 
    with a woman, or vice versa, which is as a result of mixing and lengthy 
    interaction. 
5 – It also 
    results in destruction of families. How many men have neglected their homes 
    and families because of being attracted to a colleague at school or at work. 
    How many women have neglected their husbands and homes, for the same reason. 
    How many cases of divorce have occurred because of haraam relationships 
    engaged in by the husband or wife, where mixing at work was the thing that 
    led to it. 
For these 
    and other reasons, Islam forbids mixing that can lead to these evil 
    consequences. We have quoted the evidence for the prohibition on mixing in 
    detail in the answer to question no. 
    1200. 
Based on 
    this, our advice to you is to leave this mixed workplace and look for 
    another job where you will be free from these haraam things. You should also 
    be certain that whoever gives up something for the sake of Allaah, Allaah 
    will compensate him with something better than it, and whoever fears Allaah, 
    Allaah will grant him a way out from every difficulty. 
“And 
    whosoever fears Allaah and keeps his duty to Him, He will make a way for him 
    to get out (from every difficulty).
3. And He 
    will provide him from (sources) he never could imagine”

    [al-Talaaq 65:2-3]
If you have 
    to stay in this job, then fear Allaah and lower your gaze and do not look at 
    women. Avoid shaking hands with them or being alone with them, ands remember 
    that Allaah is always watching. Remember that He knows what is secret and 
    what is yet more hidden, and He “knows the fraud of the eyes, and all 
    that the hearts conceal” [Ghaafir 40:19]. 
May Allaah 
    guide us to fear Him, and to remain chaste and independent of means.
And Allaah 
    knows best.