What is the best time to get your car refuelled at the filling station ?

I found following help material for the same discussion.

Fueling your vehicle at dusk is just one of the summertime tips to help protect against the formation of ground-level ozone, a form of pollution that increases in these days full of sunshine, hot temperatures and stagnant air.

Protecting against the formation of ozone may sound a little confusing, given that we're always hearing about the need to protect the ozone. The ozone we want to protect is in the stratosphere (upper atmosphere). That ozone is good because it protects us from UV (ultraviolet) radiation. Ground-level ozone (in the troposphere) is bad. It is formed when VOCs (volatile organic chemicals) react with NOx (nitrogen oxides) in the presence of sunlight and heat. Major sources of these ozone precursors include motor vehicle exhaust, industrial emissions and chemical solvents.

Ground-level ozone aggravates your respiratory system, decreases lung function and may cause permanent lung damage. According to the Environmental Protection Agency, approximately one out of every three people is at risk for high ozone health effects. This includes children, those with asthma or existing respiratory problems and adults of all ages who actively work or exercise outdoors (which would include virtually everyone in exercise-loving Boulder County).

Humans, of course, are not the only ones to suffer. Ground-level ozone also damages plants and ecosystems. It interferes with the ability of plants to produce and store food, increasing their susceptibility to pests, severe weather, disease, etc. Ozone also damages the aesthetic quality of the leaves of plants and trees, and reduces crop and forest yields.

The good news is that by following a few simple steps, we can reduce this summertime pollution. Here are a few suggestions from the Regional Air Quality Council (RAQC) and from the Colorado Department of Public Health and the Environment:

Limit driving, combine trips or use alternative transportation. According to RAQC, operating and refueling vehicles accounts for 35 percent to 50 percent of ozone formation in the Denver metro area.

Stop at the click and don't overfill at the pump. Refueling at dusk/night is preferable because the fuel vapors do not have so much of a chance to "cook" in the midday sun.

Turn your gas cap until it clicks three times to ensure that harmful pollutants are not seeping out of your gas tank.

Avoid using gas-powered yard equipment on high ozone days. Let the grass grow another day. If you must, wait until later in the day.

Substitute an electric starter or charcoal chimney for lighter fluid in your BBQ.

Painting, stripping and refinishing projects typically contain VOCs. Postpone using these products until later in the day to avoid morning and midday heat. Better yet, postpone until fall and use low VOC water-based paints and stains.

Avoid idling your car for more than 30 seconds. Choose to go inside rather than sit in long drive-thru lines.

Tightly seal the lids on chemical products to avoid evaporation.

Keep your car properly tuned and maintained. Simple steps like checking the tire pressure weekly and regular oil changes can go a long way.

Dear Mr. Dipen,

Please never mind in this aspect, ofcourse this is much tech. involved. Thats why this question has been put in 'Automotive TECH talk'

Regards

I would recommand this because the viscosity plays a role in the quantity/sec delivered may be appropriate.